Bio

Clinical Focus


  • Myositis
  • Muscular Dystrophies
  • Amyotrophic Lateral Sclerosis
  • Electromyography
  • Myasthenia Gravis
  • Neurology
  • Neuropathy

Academic Appointments


Administrative Appointments


  • Director, Residency Program, Department of Neurology (1999 - 2010)
  • Director, Neurology Clinics, Department of Neurology (1999 - Present)

Honors & Awards


  • AAMC Humanism in Medicine Award, Association of American Medical Colleges (2005)
  • America’s Top Physicians, Consumers’ Research Council of America (2004)
  • Best Doctors in America, Best Doctors, Inc. (2003-present)
  • L. Forno Award for Teaching Excellence, Stanford Department of Neurology (1999)
  • Elected member, American Neurological Association (1997)

Boards, Advisory Committees, Professional Organizations


  • Chair, Practice Issues Review Panel, American Association of Neuromuscular and Electrodiagnostic Medicine (2007 - Present)
  • Co-Chair, Therapeutics and Technology Assessment Subcommittee, American Academy of Neurology (2003 - 2009)

Professional Education


  • Board Certification: Neuromuscular Medicine, American Board of Psychiatry and Neurology (2011)
  • Internship:UCSF Medical Center (1984) CA
  • Medical Education:Yale University School of Medicine (1982) CT
  • Fellowship:UCSF Medical Center (1988) CA
  • Residency:UCSF Medical Center (1987) CA
  • Board Certification: Neurology, American Board of Psychiatry and Neurology (1989)
  • BS, Northwestern University
  • PhD, Rockefeller University
  • MD, Yale University

Research & Scholarship

Current Research and Scholarly Interests


Research in the diagnosis, pathophysiology and treatment of peripheral neuropathy, motor neuron diseases including ALS and SMA, nerve injuries and muscle diseases. Application of clinical neurophysiological methods to neurological diagnosis. Neurological complications of HIV infection. Development of evidence-based medicine pertaining to the practice of neurology.

Clinical Trials


  • Development and Validation of a Disability Severity Index for CMT Recruiting

    It is necessary for outcome measures to accurately reflect the state of health of a person in order for clinical trials to show benefit. The most commonly used outcome measure for Charcot Marie Tooth Disease (CMT) is the CMT Neuropathy Score, which uses cutoffs of points designated as mild (0-10 points), moderate (11-20) or severe (21-36). These terms are arbitrary. This study is looking to base mild, moderate, and severe on what both people affected with CMT and those who provide for people with CMT consider appropriate.

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  • A Study to Evaluate the Efficacy and Safety of Alglucosidase Alfa Produced at the 4000 L Scale for Pompe Disease Recruiting

    The objective of this study is to evaluate the efficacy and safety of treatment with 4000 L alglucosidase alfa (Lumizyme®) in Pompe patients.

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  • Pharmacodynamic Study of CK-2017357 in Patients With Generalized Myasthenia Gravis Not Recruiting

    The primary objective of this early-stage clinical study is to demonstrate an effect of single doses of CK-2017357 on measures of skeletal muscle function and fatigability in patients with generalized myasthenia gravis (MG).

    Stanford is currently not accepting patients for this trial. For more information, please contact Shirely Paulose, 650-724-3792.

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  • A Clinical Study to Assess Two Doses of GSK2402968 in Subjects With Duchenne Muscular Dystrophy (DMD) Not Recruiting

    The purpose of this study is to determine if GSK2402968 is effective in the treatment of ambulant boys with Duchenne muscular dystrophy resulting from a mutation thought to be corrected by exon 51 skipping. Two doses of GSK2402968 and placebo will be used in this study.

    Stanford is currently not accepting patients for this trial. For more information, please contact Shirley Paulose , 650-724-3792 .

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  • Drisapersen Duchenne Muscular Dystrophy (DMD) Treatment Protocol Not Recruiting

    This is a single arm, open-label continued access protocol of drisapersen for the treatment of male subjects with Duchenne muscular dystrophy (DMD) having dystrophin mutations correctable by drisapersen-induced DMD Exon 51 skipping. The purpose of this continued access protocol is to offer pre-approval access to drisapersen for the treatment of subjects with DMD who previously participated in eligible drisapersen studies. The protocol will collect safety data required to assure subject safety and periodic efficacy data on muscle function.

    Stanford is currently not accepting patients for this trial. For more information, please contact Shirley Paulose, 650-724-3792.

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  • Diaphragm Pacing System (DPS) In Participants With Amyotrophic Lateral Sclerosis (ALS) Recruiting

    The study is being conducted to determine if DPS treatment for people with ALS and hypoventilation is associated with improved survival or diaphragm function. The primary objective of the study is to conduct a multi-center, randomized controlled clinical trial comparing standard of care (control) to diaphragm stimulator treatment with the NeuRx® Diaphragm Pacing System™ (DPS) with respect to survival. The secondary objective of the study is to conduct a multi-center, randomized controlled clinical trial to compare standard of care treatment (control) to DPS in ALS subjects with hypoventilation.

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  • Humanitarian Device Exemption Post-Approval Study of NeuRx Diaphragm Pacing System for Amyotrophic Lateral Sclerosis Recruiting

    This post-approval study will follow 60 participants who have ALS, documented chronic hypoventilation, and bilateral phrenic nerve function, and who undergo the surgical implantation procedure to receive the NeuRx Diaphragm Pacing System device. Participants who are successfully implanted with the device will use it for daily diaphragm conditioning sessions. Participants will be followed for at least two years (until the last enrolled participant reaches the 2-year follow-up visit). Safety and probable benefit outcome measures will be assessed.

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  • A Study to Explore the Safety and Tolerability of Acthar in Patients With Amyotrophic Lateral Sclerosis Recruiting

    This 8-week randomized, open-label evaluation will examine the acute safety and tolerability of 4 different dosing regimens of Acthar to inform dose selection for future studies of Acthar in patients with Amyotrophic Lateral Sclerosis (ALS). The study will also investigate the mean rate of change in the ALSFRS-R total score as an exploratory endpoint to help design future studies. This study will enroll up to 40 patients and include an optional 28-week open-label extension period plus a 3-week treatment taper and 1-week follow up period. After completion of Week 8, patients enrolled in a treatment group that is considered safe and tolerable at that time have the option to continue into the open-label extension period. A 3-week treatment taper and a follow-up visit are planned for all patients enrolled in the study, beginning either at Week 8 or at Week 36 if a patient continues into the optional open-label extension period.

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Teaching

2013-14 Courses


Publications

Journal Articles


  • Progressive cerebral injury in the setting of chronic HIV infection and antiretroviral therapy JOURNAL OF NEUROVIROLOGY Gongvatana, A., Harezlak, J., Buchthal, S., Daar, E., Schifitto, G., Campbell, T., Taylor, M., Singer, E., Algers, J., Zhong, J., Brown, M., McMahon, D., So, Y. T., Mi, D., Heaton, R., Robertson, K., Yiannoutsos, C., Cohen, R. A., Navia, B. 2013; 19 (3): 209-218

    Abstract

    Emerging evidence suggests that CNS injury and neurocognitive impairment persist in the setting of chronic HIV infection and combination antiretroviral therapy (CART). Yet, whether neurological injury can progress in this setting remains uncertain. Magnetic resonance spectroscopy and neurocognitive and clinical assessments were performed over 2 years in 226 HIV-infected individuals on stable CART, including 138 individuals who were neurocognitively asymptomatic (NA). Concentrations of N-acetylaspartate (NAA), creatine (Cr), choline (Cho), myoinositol, and glutamate/glutamine (Glx) were measured in the midfrontal cortex (MFC), frontal white matter (FWM), and basal ganglia (BG). Longitudinal changes in metabolite levels were determined using linear mixed effect models, as were metabolite changes in relation to global neurocognitive function. HIV-infected subjects showed significant annual decreases in brain metabolite levels in all regions examined, including NAA (2.95 %) and Cho (2.61 %) in the FWM; NAA (1.89 %), Cr (1.84 %), Cho (2.19 %), and Glx (6.05 %) in the MFC; and Glx (2.80 %) in the BG. Similar metabolite decreases were observed in the NA and subclinically impaired subgroups, including subjects with virologic suppression in plasma and CSF. Neurocognitive decline was associated with longitudinal decreases in Glx in the FWM and the BG, and in NAA in the BG. Widespread progressive changes in the brain, including neuronal injury, occur in chronically HIV-infected persons despite stable antiretroviral treatment and virologic suppression and can lead to neurocognitive declines. The basis for these findings is poorly understood and warrants further study.

    View details for DOI 10.1007/s13365-013-0162-1

    View details for Web of Science ID 000321129800003

    View details for PubMedID 23613008

  • Effects of noninvasive ventilation on sleep outcomes in amyotrophic lateral sclerosis. Journal of clinical sleep medicine Katzberg, H. D., Selegiman, A., Guion, L., Yuan, N., Cho, S. C., Katz, J. S., Miller, R. G., So, Y. T. 2013; 9 (4): 345-351

    Abstract

    The objective was to study the effects on noninvasive ventilation on sleep outcomes in patient with ALS, specifically oxygenation and overall sleep quality.Patients with ALS who met criteria for initiation of NIV were studied with a series of 2 home PSG studies, one without NIV and a follow-up study while using NIV. Primary outcome was a change in the maximum overnight oxygen saturation; secondary outcomes included change in mean overnight oxygen saturation, apnea and hypopnea indexes, sleep latency, sleep efficiency, sleep arousals, and sleep architecture.A total of 94 patients with ALS were screened for eligibility; 15 were enrolled; and 12 completed study procedures. Maximum overnight oxygen saturation improved by 7.0% (p = 0.01) and by 6.7% during REM sleep (p = 0.02) with NIV. Time spent below 90% oxygen saturation was also significant-ly better with NIV (30% vs 19%, p < 0.01), and there was trend for improvement in mean overnight saturation (1.5%, p = 0.06). Apnea index (3.7 to 0.7), hypopnea index (6.2 to 5.7), and apnea hypopnea index (9.8 to 6.3) did not significantly improve after introducing NIV. NIV had no effect on sleep efficiency (mean change 10%), arousal index (7 to 12), or sleep stage distribution (Friedman chi-squared = 0.40).NIV improved oxygenation but showed no significant effects on sleep efficiency, sleep arousals, restful sleep, or sleep architecture. The net impact of these changes for patients deserves further study in a larger group of ALS patients.

    View details for DOI 10.5664/jcsm.2586

    View details for PubMedID 23585750

  • Evidence-based guideline: IV immunoglobulin in the treatment of neuromuscular disorders: report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology. Neurology Li, H., Gao, X., Hong, Y., Patwa, H. S., Chaudhry, V., Rae-Grant, A. D., So, Y. T., Alto, P. 2012; 79 (13): 1411-?

    View details for PubMedID 23008223

  • Evidence-based guideline: Intravenous immunoglobulin in the treatment of neuromuscular disorders Report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology NEUROLOGY Patwa, H. S., Chaudhry, V., Katzberg, H., Rae-Grant, A. D., So, Y. T. 2012; 78 (13): 1009-1015

    Abstract

    To assess the evidence for the efficacy of IV immunoglobulin (IVIg) to treat neuromuscular disorders.The MEDLINE, Web of Science, and EMBASE databases were searched (1966-2009). Selected articles were rated according to the American Academy of Neurology's therapeutic classification of evidence scheme; recommendations were based on the evidence level.IVIg is as efficacious as plasmapheresis and should be offered for treating Guillain-Barré syndrome (GBS) in adults (Level A). IVIg is effective and should be offered in the long-term treatment of chronic inflammatory demyelinating polyneuropathy (Level A). IVIg is probably effective and should be considered for treating moderate to severe myasthenia gravis and multifocal motor neuropathy (Level B). IVIg is possibly effective and may be considered for treating nonresponsive dermatomyositis in adults and Lambert-Eaton myasthenic syndrome (Level C). Evidence is insufficient to support or refute use of IVIg in the treatment of immunoglobulin M paraprotein-associated neuropathy, inclusion body myositis, polymyositis, diabetic radiculoplexoneuropathy, or Miller Fisher syndrome, or in the routine treatment of postpolio syndrome or in children with GBS (Level U). IVIg combined with plasmapheresis should not be considered for treating GBS (Level B). More data are needed regarding IVIg efficacy as compared with other treatments/treatment combinations. Most studies concluded IVIg-related serious adverse effects were rare. Given the variable nature of these diseases, individualized treatments depending on patient need and physician judgment are important.

    View details for Web of Science ID 000302125600017

    View details for PubMedID 22454268

  • Immune-mediated neuropathies. Continuum (Minneapolis, Minn.) So, Y. T. 2012; 18 (1): 85-105

    Abstract

    The immune-mediated neuropathies are an important group of treatable neuropathies that often lead to severe neurologic disability. This review guides clinicians in the recognition and treatment of these disorders.Advances include new insights in classification and new treatment paradigms in many of these disorders.Proper diagnosis and treatment require recognition of the characteristic clinical and laboratory findings and the use of appropriate electrophysiologic or pathologic examination. With proper treatment, partial or complete remission is possible, even in patients who are severely affected.

    View details for DOI 10.1212/01.CON.0000411569.72203.9d

    View details for PubMedID 22810071

  • New insights into small fiber neuropathy ANNALS OF NEUROLOGY So, Y. 2012; 71 (1): 3-4

    View details for DOI 10.1002/ana.22666

    View details for Web of Science ID 000299412200004

    View details for PubMedID 22275247

  • Cost comparison between the atraumatic and cutting lumbar puncture needles NEUROLOGY Tung, C. E., So, Y. T., Lansberg, M. G. 2012; 78 (2): 109-113

    Abstract

    The aim of this study was to determine which type of spinal needle is preferred from a cost perspective, taking into account costs of the spinal needle and treatment of postlumbar puncture headache.A decision-analytic model was created to determine the cost of diagnostic lumbar punctures using atraumatic and cutting needles. We assumed a health care system perspective and based the analysis on the treatment of a patient facing event probabilities derived from prior studies. The economic outcome measure was the difference in estimated costs between the 2 needles. One-way and probabilistic sensitivity analyses tested the robustness of the model.Lumbar puncture performed with the atraumatic needle is associated with an average cost savings of $26.07 per patient. Average total health care costs are $166.08 with the atraumatic needle, compared to $192.15 with the cutting needle. There is 94% certainty that the atraumatic needle is cost-saving compared to the cutting needle based on probabilistic sensitivity analysis. Use of the atraumatic needle over the cutting needle by neurologists alone may result in $10.4 million in cost savings to the US health care system per year.The atraumatic spinal needle is associated with an overall cost savings to the US health care system. The balance of costs and benefits favors the use of the atraumatic needle over the cutting needle for diagnostic lumbar puncture.

    View details for Web of Science ID 000299159700010

    View details for PubMedID 22205758

  • ANALYSIS OF CONTINUOUS DIAPHRAGM ELECTROMYOGRAPHIC SIGNAL: RESULTS FROM A PATIENT WITH AMYOTROPHIC LATERAL SCLEROSIS MUSCLE & NERVE Katzberg, H. D., Barros, D. F., Widrow, B., Cho, C. S., So, Y. T. 2011; 43 (6): 801-806

    Abstract

    Analysis of continuous diaphragm electromyography (dEMG) has not been well studied. We describe a system of analyzing continuous dEMG using implanted electrodes.dEMG signal was acquired via two pairs of electrodes near the diaphragm motor points. Raw bursts of dEMG signal were compared to externally captured electrocardiogram (ECG) using adaptive filtering in order to remove cardiac contamination. Differential energy levels were used to identify each dEMG burst, and average amplitude and area values from both hemidiaphragms were aggregated and averaged for the duration of the recording.A 64-year-old patient with amyotrophic lateral sclerosis underwent three serial dEMG studies every 6 months. An average of three tracings were collected per visit, and all had excellent intertest reliability (? > 0.8). Average dEMG area correlated with forced vital capacity and mean inspiratory pressure (r(2) > 0.9).The approach described represents a comprehensive method for capturing and analyzing continuous diaphragm EMG signal.

    View details for DOI 10.1002/mus.21985

    View details for Web of Science ID 000291214200004

    View details for PubMedID 21607964

  • Evidence-based guideline update: Plasmapheresis in neurologic disorders Report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology NEUROLOGY Cortese, I., Chaudhry, V., So, Y. T., Cantor, F., Cornblath, D. R., Rae-Grant, A. 2011; 76 (3): 294-300

    Abstract

    To reassess the role of plasmapheresis in the treatment of neurologic disorders.We evaluated the available evidence based on a structured literature review for relevant articles from 1995 through September 2009. In addition, due to revision of the definitions of classification of evidence since the publication of the previous American Academy of Neurology assessment in 1996, the evidence cited in that manuscript was reviewed and reclassified.Plasmapheresis is established as effective and should be offered in severe acute inflammatory demyelinating polyneuropathy (AIDP)/Guillain-Barré syndrome (GBS) and in the short-term management of chronic inflammatory demyelinating polyneuropathy (Class I studies, Level A). Plasmapheresis is established as ineffective and should not be offered for chronic or secondary progressive multiple sclerosis (MS) (Class I studies, Level A). Plasmapheresis is probably effective and should be considered for mild AIDP/GBS, as second-line treatment of steroid-resistant exacerbations in relapsing forms of MS, and for neuropathy associated with immunoglobulin A or immunoglobulin G gammopathy, based on at least one Class I or 2 Class II studies (Level B). Plasmapheresis is probably not effective and should not be considered for neuropathy associated with immunoglobulin M gammopathy, based on one Class I study (Level B). Plasmapheresis is possibly effective and may be considered for acute fulminant demyelinating CNS disease (Level C). There is insufficient evidence to support or refute the use of plasmapheresis for myasthenia gravis, pediatric autoimmune neuropsychiatric disorders associated with streptococcus infection, and Sydenham chorea (Class III evidence, Level U).

    View details for Web of Science ID 000286371900019

    View details for PubMedID 21242498

  • End-Stage Cardiac Disease as an Initial Presentation of Systemic Myopathies: Case Series and Literature Review JOURNAL OF CHILD NEUROLOGY Katzberg, H., Karamchandani, J., So, Y. T., Vogel, H., Wang, C. H. 2010; 25 (11): 1382-1388

    Abstract

    Life-threatening cardiomyopathy is associated with certain systemic myopathies and usually presents as an end-stage progression of the disease. However, cardiac symptoms can sometimes precede muscle weakness. The authors reviewed medical records from 2003 to 2008 on patients attending their neuromuscular clinic and identified patients who initially presented with an end-stage cardiomyopathy and were later diagnosed with a specific muscle disease through muscle biopsy. They report 5 cases of children who initially presented with cardiomyopathies without neuromuscular symptoms. The cardiac symptoms were so severe that 4 of them required cardiac transplantation and 1 died prior to transplantation. Review of muscle pathology confirmed the diagnoses of Becker muscular dystrophy, myofibrillar myopathy, mitochondrial myopathy with cytochrome oxidase deficiency, Danon disease, and glycogen storage disease. The authors conclude that cardiomyopathy can be the initial presentation of a wide spectrum of systemic myopathies. Careful evaluation of neuromuscular systems should be carried out in patients presenting with end-stage cardiomyopathies.

    View details for DOI 10.1177/0883073810367683

    View details for Web of Science ID 000284155600012

    View details for PubMedID 20445193

  • Chemotherapy-related polyneuropathy may deteriorate quality of life in patients with B-cell lymphoma QUALITY OF LIFE RESEARCH Kim, B., Park, H., Roh, H. J., Jeong, D., Kim, B. S., Park, K., Cho, S. C., So, Y. T., Oh, S. Y., Kim, S. J. 2010; 19 (8): 1097-1103

    Abstract

    This prospective study was performed to evaluate the effect of chemotherapy-related neurotoxicity on quality of life (QOL) of patients with lymphoma.Thirty-two patients with diffuse large B-cell or follicular lymphoma without prior evidence of neuropathy were enrolled. Patients underwent the evaluations based on neuropathy symptom and disability score, nerve conduction studies, and SF-36 questionnaire for QOL assessment. They received six cycles of chemotherapy every three weeks, and all evaluations were repeated during and after the completion of 6th cycle.Sensory neuropathy-associated symptoms were observed in 27 patients (84.4%), and polyneuropathy was confirmed by nerve conduction study in 14 patients (43.8%). These patients with polyneuropathy showed worse QOL in domains mainly associated with physical health status including "physical function" compared to patients without polyneuropathy. There was a significant association of neuropathy symptom and disability scores with "bodily pain" and "vitality" of QOL domains. The serial evaluations of patients with neuropathy showed a worsening of QOL and neuropathy symptom scores during chemotherapy, then improvement of these values after chemotherapy. Thus, the final nerve conduction study confirmed the decrease in polyneuropathy compared to the 2nd evaluation (P = 0.032).Chemotherapy-related polyneuropathy may deteriorate QOL of patients with lymphoma, mainly physical health-associated QOL.

    View details for DOI 10.1007/s11136-010-9670-0

    View details for Web of Science ID 000281902800002

    View details for PubMedID 20443066

  • UTILITY OF ELECTRODIAGNOSTIC TESTING IN EVALUATING PATIENTS WITH LUMBOSACRAL RADICULOPATHY: AN EVIDENCE-BASED REVIEW MUSCLE & NERVE Cho, S. C., Ferrante, M. A., Levin, K. H., Harmon, R. L., So, Y. T. 2010; 42 (2): 276-282

    Abstract

    This is an evidence-based review of electrodiagnostic (EDX) testing of patients with suspected lumbosacral radiculopathy to determine its utility in diagnosis and prognosis. Literature searches were performed to identify articles applying EDX techniques to patients with suspected lumbosacral radiculopathy. From the 355 articles initially discovered, 119 articles describing nerve conduction studies, electromyography (EMG), or evoked potentials in adequate detail were reviewed further. Fifty-three studies met inclusion criteria and were graded using predetermined criteria for classification of evidence for diagnostic studies. Two class II, 7 class III, and 34 class IV studies described the diagnostic use of EDX. One class II and three class III articles described H-reflexes with acceptable statistical significance for use in the diagnosis and confirmation of suspected S1 lumbosacral radiculopathy. Two class II and two class III studies demonstrated a range of sensitivities for use of muscle paraspinal mapping. Two class II studies demonstrated the utility of peripheral myotomal limb electromyography in radiculopathies.

    View details for DOI 10.1002/mus.21759

    View details for Web of Science ID 000280374000021

    View details for PubMedID 20658602

  • Utility of the cutaneous silent period in patients with diabetes mellitus JOURNAL OF THE NEUROLOGICAL SCIENCES Kim, B., Kim, N., Kim, S. G., Roh, H., Park, H., Park, M., Park, K., Cho, S. C., So, Y. T. 2010; 293 (1-2): 1-5

    Abstract

    We performed this study to evaluate whether or not the cutaneous silent period (CSP) is a useful metric to identify small-fiber neuropathy in diabetic patients. The CSP was measured from the abductor pollicis brevis muscle in 30 healthy controls and 110 diabetic patients, who in turn were divided into 3 subgroups (patients with large-fiber neuropathy, patients with small-fiber neuropathy, and asymptomatic patients). The measured CSP and clinical characteristics were compared among the groups. The power of the CSP in discriminating patients from controls and any correlation with other clinical variables were analyzed. Each patient subgroup had a significantly delayed CSP latency compared to the controls. The latency of patients with large-fiber neuropathy was also significantly prolonged compared to the other subgroups of patients. The CSP latency was the only variable to discriminate patients. The latency showed a significant correlation with the late responses in nerve conduction studies. Thus, the CSP latency may be a useful tool in evaluating small neural fiber function in diabetic patients.

    View details for DOI 10.1016/j.jns.2010.03.032

    View details for Web of Science ID 000278652500001

    View details for PubMedID 20417526

  • DRIVING WITH POLYNEUROPATHY MUSCLE & NERVE Cho, S. C., Katzberg, H. D., Rama, A., Kim, B., Roh, H., Park, J., Katz, J., So, Y. T. 2010; 41 (3): 324-328

    Abstract

    Polyneuropathy may result in pain, numbness, and weakness, which may in turn affect driving ability. Medications used to treat neuropathic pain may alter cognition, which may further affect driving. Although such impairments have engendered questions about the driving safety in this group of patients, the rate of motor vehicle accidents (MVAs) in patients with neuropathy has not been studied rigorously. We surveyed patients with neuropathy from three medical centers for reported accident rate, and we analyzed variables related to increased risk for accidents compared to National Highway Traffic Safety Administration data. Surveys from 260 subjects demonstrated that 40.6% were involved in traffic accidents (0.11 accidents/year). Their accident rate was 10.8 MVAs per million vehicle miles traveled (MVA/MVMT), compared to 3.71 MVA/MVMT in 55-59-year-old drivers and 3.72 in 60-64-year-olds (National Highway Traffic Safety Administration data). In all, 72.4% cited their neuropathy and 55.2% cited their medications as playing a role in their accidents, and 51.6% changed their driving habits after developing neuropathy. Independently, elevated levels of pain, motor weakness, and ambulation difficulty met statistical significance for increased MVA frequency. We conclude that accident frequency and discomfort with driving are higher in neuropathy patients compared to age-matched national statistics. However, most patients seem to change habits according to their ability to drive; as such, driving issues should be addressed with caution and on a case-by-case basis.

    View details for DOI 10.1002/mus.21511

    View details for Web of Science ID 000275139700005

    View details for PubMedID 19882633

  • Assessment: Symptomatic treatment for muscle cramps (an evidence-based review) Report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology NEUROLOGY Katzberg, H. D., Khan, A. H., So, Y. T. 2010; 74 (8): 691-696

    Abstract

    A Food and Drug Administration advisory in 2006 warned against the off-label use of quinine sulfate and its derivatives in the treatment of muscle cramps. Physicians are faced with a difficult scenario in choosing a treatment regimen for patients with muscle cramps. This American Academy of Neurology assessment systematically reviews the available evidence on the symptomatic treatment of muscle cramps.A total of 563 potential articles were reviewed, of which 24 met the inclusion criteria of prospective trials evaluating the efficacy of a particular treatment on muscle cramps as a primary or secondary outcome.There are Class I studies showing the efficacy of quinine derivatives for treatment of muscle cramps. However, the benefit is modest and there are adverse effects from published prospective trials as well as case reports. There is one Class II study each to support the use of Naftidrofuryl, vitamin B complex, lidocaine, and diltiazem in the treatment of muscle cramps. Recommendations: Although likely effective (Level A), quinine derivatives should be avoided for routine use in the management of muscle cramps because of the potential of toxicity, but in select patients they can be considered for an individual therapeutic trial once potential side effects are taken into account. Vitamin B complex, Naftidrofuryl, and calcium channel blockers such as diltiazem are possibly effective and may be considered in the management of muscle cramps (Level C). Further studies are needed to identify agents that are effective and safe for the treatment of muscle cramps.

    View details for Web of Science ID 000274796900013

    View details for PubMedID 20177124

  • ASSESSMENT: BOTULINUM NEUROTOXIN FOR THE TREATMENT OF SPASTICITY (AN EVIDENCE-BASED REVIEW) NEUROLOGY Dobkin, B. H. 2009; 73 (9): 736-736

    View details for Web of Science ID 000269444200016

    View details for PubMedID 19720984

  • THE VALUE OF ELECTROMYOGRAPHY: TOWARD AN EVIDENCE-BASED USE OF ELECTRODIAGNOSTIC TESTING MUSCLE & NERVE So, Y. T. 2009; 40 (2): 171-172

    View details for DOI 10.1002/mus.21375

    View details for Web of Science ID 000269849700002

    View details for PubMedID 19609899

  • Disorders of the Trigeminal System SEMINARS IN NEUROLOGY Gonella, M. C., Fischbein, N. J., So, Y. T. 2009; 29 (1): 36-44

    Abstract

    The management of patients with trigeminal system dysfunction requires an understanding of the system's complex anatomy, which extends from peripheral nerve endings, through the skull base, cavernous sinus (V1, V2 only), and trigeminal ganglion, to the intraaxial nuclei, tracts, and cerebral cortex. The differential diagnosis is broad. Seemingly minor facial sensory loss may indicate an underlying malignancy (as in numb-chin syndrome). Painful syndromes of the trigeminal nerve are numerous and require careful categorization. Understanding trigeminal system anatomy and the appropriate use of imaging and electrodiagnostics should aid in the diagnosis and treatment of these disorders.

    View details for DOI 10.1055/s-0028-1124021

    View details for Web of Science ID 000265871900006

    View details for PubMedID 19214931

  • Assessment: botulinum neurotoxin for the treatment of spasticity (an evidence-based review). Neurology Simpson, D. M., Gracies, J. M., Graham, K., Hallett, M., Miyasaki, J., Naumann, M., Russman, B., Simpson, L., So, Y. 2009; 73 (9): 736-7; author reply 737-8

    View details for PubMedID 19728407

  • American Association of Neuromuscular & Electrodiagnostic Medicine evidenced-based review: Use of surface electromyography in the diagnosis and study of neuromuscular disorders MUSCLE & NERVE Meekins, G. D., So, Y., Quan, D. 2008; 38 (4): 1219-1224

    Abstract

    Surface electromyography (sEMG) measures myoelectrical signals recorded from sensors placed on the skin surface. The non-invasive nature of sEMG makes it a potentially useful technology for studying diseases of muscle and nerve. Reviews published by the American Association of Neuromuscular and Electrodiagnostic Medicine (AANEM) and the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology (AAN), covering 1964-1994 and 1952-1998, respectively, concluded that sEMG adds no clinical utility over conventional needle EMG (nEMG) for the diagnosis of neuromuscular disease. The AANEM sEMG task force reevaluated the diagnostic utility and added value of this technology for the study of neuromuscular disease based on a contemporary review of relevant literature published between January 1994 and February 2006. The present review concludes that sEMG may be useful to detect the presence of neuromuscular disease (level C rating, class III data), but there are insufficient data to support its utility for distinguishing between neuropathic and myopathic conditions or for the diagnosis of specific neuromuscular diseases. sEMG may be useful for additional study of fatigue associated with post-poliomyelitis syndrome and electromechanical function in myotonic dystrophy (level C rating, class III data).

    View details for DOI 10.1002/mus.21055

    View details for Web of Science ID 000259843700001

    View details for PubMedID 18816611

  • Assessment: Botulinum neurotoxin for the treatment of spasticity (an evidence-based review) - Report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology NEUROLOGY Simpson, D. M., Gracies, J., Graham, H. K., Miyasaki, J. M., NAUMANN, M., Russman, B., Simpson, L. L., So, Y. 2008; 70 (19): 1691-1698

    Abstract

    To perform an evidence-based review of the safety and efficacy of botulinum neurotoxin (BoNT) in the treatment of adult and childhood spasticity.A literature search was performed including MEDLINE and Current Contents for therapeutic articles relevant to BoNT and spasticity. Authors reviewed, abstracted, and classified articles based on American Academy of Neurology criteria (Class I-IV).The highest quality literature available for the respective indications was as follows: adult spasticity (14 Class I studies); spastic equinus and adductor spasticity in pediatric cerebral palsy (six Class I studies).Botulinum neurotoxin should be offered as a treatment option for the treatment of spasticity in adults and children (Level A).

    View details for Web of Science ID 000256707100009

    View details for PubMedID 18458229

  • Assessment: Botulinum neurotoxin for the treatment of movement disorders (an evidence-based review) - Report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology NEUROLOGY Simpson, D. M., Blitzer, A., Brashear, A., Comella, C., Dubinsky, R., Hallett, M., Jankovic, J., Karp, B., Ludlow, C. L., Miyasaki, J. M., NAUMANN, M., So, Y. 2008; 70 (19): 1699-1706

    Abstract

    To perform an evidence-based review of the safety and efficacy of botulinum neurotoxin (BoNT) in the treatment of movement disorders.A literature search was performed including MEDLINE and Current Contents for therapeutic articles relevant to BoNT and selected movement disorders. Authors reviewed, abstracted, and classified articles based on American Academy of Neurology criteria (Class I-IV).The highest quality literature available for the respective indications was as follows: blepharospasm (two Class II studies); hemifacial spasm (one Class II and one Class III study); cervical dystonia (seven Class I studies); focal upper extremity dystonia (one Class I and three Class II studies); focal lower extremity dystonia (one Class II study); laryngeal dystonia (one Class I study); motor tics (one Class II study); and upper extremity essential tremor (two Class II studies).Botulinum neurotoxin should be offered as a treatment option for the treatment of cervical dystonia (Level A), may be offered for blepharospasm, focal upper extremity dystonia, adductor laryngeal dystonia, and upper extremity essential tremor (Level B), and may be considered for hemifacial spasm, focal lower limb dystonia, and motor tics (Level C). While clinicians' practice may suggest stronger recommendations in some of these indications, evidence-based conclusions are limited by the availability of data.

    View details for Web of Science ID 000256707100010

    View details for PubMedID 18458230

  • Assessment: Botulinum neurotoxin in the treatment of autonomic disorders and pain (an evidence-based review) - Report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology NEUROLOGY Naumann, M., So, Y., Argoff, C. E., Childers, M. K., Dykstra, D. D., Gronseth, G. S., Jabbari, B., Kaufmann, H. C., Schurch, B., Silberstein, S. D., Simpson, D. M. 2008; 70 (19): 1707-1714

    Abstract

    To perform an evidence-based review of the safety and efficacy of botulinum neurotoxin (BoNT) in the treatment of autonomic and urologic disorders and low back and head pain.A literature search was performed including MEDLINE and Current Contents for therapeutic articles relevant to BoNT and the selected indications. Authors reviewed, abstracted, and classified articles based on the quality of the study (Class I-IV). Conclusions and recommendations were developed based on the highest level of evidence and put into current clinical context.The highest quality literature available for the respective indications was as follows: axillary hyperhidrosis (two Class I studies); palmar hyperhidrosis (two Class II studies); drooling (four Class II studies); gustatory sweating (five Class III studies); neurogenic detrusor overactivity (two Class I studies); sphincter detrusor dyssynergia in spinal cord injury (two Class II studies); chronic low back pain (one Class II study); episodic migraine (two Class I and two Class II studies); chronic daily headache (four Class II studies); and chronic tension-type headache (two Class I studies).Botulinum neurotoxin (BoNT) should be offered as a treatment option for the treatment of axillary hyperhidrosis and detrusor overactivity (Level A), should be considered for palmar hyperhidrosis, drooling, and detrusor sphincter dyssynergia after spinal cord injury (Level B), and may be considered for gustatory sweating and low back pain (Level C). BoNT is probably ineffective in episodic migraine and chronic tension-type headache (Level B). There is presently no consistent or strong evidence to permit drawing conclusions on the efficacy of BoNT in chronic daily headache (mainly transformed migraine) (Level U). While clinicians' practice may suggest stronger recommendations in some of these indications, evidence-based conclusions are limited by the availability of data.

    View details for Web of Science ID 000256707100011

    View details for PubMedID 18458231

  • Classification and prediction of clinical Alzheimer's diagnosis based on plasma signaling proteins NATURE MEDICINE Ray, S., Britschgi, M., Herbert, C., Takeda-Uchimura, Y., Boxer, A., Blennow, K., Friedman, L. F., Galasko, D. R., Jutel, M., Karydas, A., Kaye, J. A., Leszek, J., Miller, B. L., Minthon, L., Quinn, J. F., Rabinovici, G. D., Robinson, W. H., Sabbagh, M. N., So, Y. T., Sparks, D. L., Tabaton, M., Tinklenberg, J., Yesavage, J. A., Tibshirani, R., Wyss-Coray, T. 2007; 13 (11): 1359-1362

    Abstract

    A molecular test for Alzheimer's disease could lead to better treatment and therapies. We found 18 signaling proteins in blood plasma that can be used to classify blinded samples from Alzheimer's and control subjects with close to 90% accuracy and to identify patients who had mild cognitive impairment that progressed to Alzheimer's disease 2-6 years later. Biological analysis of the 18 proteins points to systemic dysregulation of hematopoiesis, immune responses, apoptosis and neuronal support in presymptomatic Alzheimer's disease.

    View details for DOI 10.1038/nm1653

    View details for Web of Science ID 000250736900029

    View details for PubMedID 17934472

  • Action at a distance: A lumbar spine tumor presenting as trigeminal neuralgia CLINICAL NEUROLOGY AND NEUROSURGERY Schwartz, N. E., Rosenberg, S., So, Y. T. 2006; 108 (8): 806-808

    Abstract

    Trigeminal neuralgia (TN) is often secondary to an underlying structural cause, frequently compression of the fifth nerve root by an ectatic artery. Here we describe a case of a 36-year-old woman with symptoms of TN who was found to have severe communicating hydrocephalus. Further investigation revealed a lumbar myxopapillary ependymoma, which in turn was responsible for the communicating hydrocephalus. An argument connecting these seemingly disparate findings is made. This unusual set of circumstances is an example of "action at a distance" in the nervous system, and reminds clinicians to think broadly about the various pathophysiologic mechanisms that can potentially underlie common disorders.

    View details for DOI 10.1016/j.clineuro.2006.02.001

    View details for Web of Science ID 000242708300019

    View details for PubMedID 16530323

  • Practice advisory: Utility of surgical decompression for treatment of diabetic neuropathy - Report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology NEUROLOGY Chaudhry, V., Stevens, J. C., Kincaid, J., So, Y. T. 2006; 66 (12): 1805-1808

    Abstract

    Surgical decompression at the site of anatomic narrowing has been promoted as an alternative treatment for patients with symptomatic diabetic neuropathy. Systematic review of the literature revealed only Class IV studies concerning the utility of this therapeutic approach. Given the current evidence available, this treatment alternative should be considered unproven (Level U). Prospective randomized controlled trials with standard definitions and outcome measures are necessary to determine the value of this therapeutic intervention.

    View details for Web of Science ID 000238572400005

    View details for PubMedID 16801641

  • HIV neuropathy natural history cohort study - Assessment measures and risk factors NEUROLOGY Simpson, D. M., Kitch, D., Evans, S. R., McArthur, J. C., Asmuth, D. M., Cohen, B., Goodkin, K., Gerschenson, M., So, Y., Marra, C. M., Diaz-Arrastia, R., Shriver, S., Millar, L., Clifford, D. B. 2006; 66 (11): 1679-1687

    Abstract

    Distal sensory polyneuropathy (DSP) is the most common neurologic complication of human immunodeficiency virus (HIV) infection. Risk factors for DSP have not been adequately defined in the era of highly active antiretroviral therapy.The authors evaluated 101 subjects with advanced HIV infection over 48 weeks. Assessments included a brief peripheral neuropathy (PN) screen (BPNS), neurologic examination, nerve conduction studies, quantitative sensory testing (QST), and skin biopsies with quantitation of epidermal nerve fiber density. Data were summed into a Total Neuropathy Score (TNS). The presence, severity, and progression of DSP were related to clinical and laboratory results.The mean TNS (range 0 to 36) was 8.9, with 38% of subjects classified as PN-free, 10% classified as having asymptomatic DSP, and 52% classified as having symptomatic DSP. Progression in TNS from baseline to week 48 occurred only in the PN-free group at baseline (mean TNS change = 1.16 +/- 2.76, p = 0.03). Factors associated with progression in TNS were lower current TNS, distal epidermal denervation, and white race. As compared with the TNS diagnosis of PN at baseline, the BPNS had a sensitivity of 34.9% and a specificity of 89.5%.In this cohort of advanced human immunodeficiency virus (HIV)-infected subjects, distal sensory polyneuropathy was common and relatively stable over 48 weeks. Previously established risk factors, including CD4 cell count, plasma HIV RNA, and use of dideoxynucleoside antiretrovirals were not predictive of the progression of distal sensory polyneuropathy (DSP). Distal epidermal denervation was associated with worsening of DSP. As compared with the Total Neuropathy Score, the brief peripheral neuropathy screen had relatively low sensitivity and high specificity for the diagnosis of DSP.

    View details for DOI 10.1212/01.wnl.0000218211.85675.18

    View details for Web of Science ID 000238223300015

    View details for PubMedID 16769940

  • Gene targeting of GAN in mouse causes a toxic accumulation of microtubule-associated protein 8 and impaired retrograde axonal transport HUMAN MOLECULAR GENETICS Ding, J. Q., Allen, E., Wang, W., Valle, A., Wu, C. B., Nardine, T., Cui, B. X., Yi, J., Taylor, A., Jeon, N. L., Chu, S., So, Y., Vogel, H., Tolwani, R., Mobley, W., Yang, Y. M. 2006; 15 (9): 1451-1463

    Abstract

    Mutations in gigaxonin were identified in giant axonal neuropathy (GAN), an autosomal recessive disorder. To understand how disruption of gigaxonin's function leads to neurodegeneration, we ablated the gene expression in mice using traditional gene targeting approach. Progressive neurological phenotypes and pathological lesions that developed in the GAN null mice recapitulate characteristic human GAN features. The disruption of gigaxonin results in an impaired ubiquitin-proteasome system leading to a substantial accumulation of a novel microtubule-associated protein, MAP8, in the null mutants. Accumulated MAP8 alters the microtubule network, traps dynein motor protein in insoluble structures and leads to neuronal death in cultured wild-type neurons, which replicates the process occurring in GAN null mutants. Defective axonal transport is evidenced by the in vitro assays and is supported by vesicular accumulation in the GAN null neurons. We propose that the axonal transport impairment may be a deleterious consequence of accumulated, toxic MAP8 protein.

    View details for DOI 10.1093/hmg/ddl069

    View details for Web of Science ID 000237002400007

    View details for PubMedID 16565160

  • High-dose cyclophosphamide in refractory myasthenia gravis with MuSK antibodies MUSCLE & NERVE Lin, P. T., Martin, B. A., Weinacker, A. B., So, Y. T. 2006; 33 (3): 433-435

    Abstract

    We describe a 48-year-old woman with seronegative myasthenia gravis (MG) and high-titer of anti-MuSK antibody. She had severe bulbar and respiratory weakness with minimal limb weakness for 2 years. Her disease responded poorly to all the conventional immunosuppressive regimens. Treatment with immunoablative dose of cyclophosphamide led to dramatic and sustained remission of her symptoms. High-dose cyclophosphamide is an effective alternative in patients with unusually refractory disease.

    View details for DOI 10.1002/mus.20411

    View details for Web of Science ID 000235646300016

    View details for PubMedID 16116645

  • Rofecoxib in the acute treatment of migraine: A randomized controlled clinical trial HEADACHE Saper, J., Dahlof, C., So, Y., Tfelt-Hansen, P., Malbecq, W., Loeys, T., Barraclough, E., Klipfel, M., Lines, C., VISSER, H., Reines, S., Yuen, E. 2006; 46 (2): 264-275

    Abstract

    To investigate the efficacy, tolerability, and safety of rofecoxib and ibuprofen for acute migraine treatment.Rofecoxib was effective and well tolerated in a previous study of treatment of a single migraine attack. We sought to replicate these findings for a single attack and also study the clinical profile of rofecoxib in the acute treatment of multiple migraine attacks. Ibuprofen was included as a reference nonselective NSAID.Adult migraineurs (n = 783) treated one migraine attack with either rofecoxib (25 or 50 mg), ibuprofen 400 mg, or placebo in a randomized, double-blind study. Patients could elect to enroll in a 3-month double-blind extension phase.In the single-attack phase, headache relief at 2 hours postdose was reported by 59.4%, 62.2%, and 57.7% of patients who took rofecoxib 25 mg, rofecoxib 50 mg, and ibuprofen 400 mg, respectively, versus 30.5% for placebo (all P < .001 vs placebo). The active drugs were statistically superior to placebo on a variety of additional measures. In the extension phase, the mean percentage of patients' attacks with headache relief at 2 hours postdose was 61.8% for rofecoxib 25 mg, 65.4% for rofecoxib 50 mg, and 59.3% for ibuprofen 400 mg. The mean percentage of patients' attacks with 24-hour sustained headache relief was greater for rofecoxib 50 mg (52.0%) than for rofecoxib 25 mg (47.8%, P < .050) or ibuprofen (39.0%, P < .010). In the single-attack phase, the adverse event rate was higher for rofecoxib 50 mg (37.8%) than placebo (27.8%, P < .050); rates were similar to placebo for rofecoxib 25 mg (32.0%, n.s.) and ibuprofen 400 mg (28.1%, n.s.). In the extension phase, treatment groups had similar adverse event rates.Rofecoxib 25 and 50 mg and ibuprofen 400 mg were effective and generally well tolerated in the acute treatment of migraine.

    View details for DOI 10.1111/j.1526-4610.2006.00334.x

    View details for Web of Science ID 000235370800013

    View details for PubMedID 16492236

  • Bilateral isolated phrenic neuropathy causing painless bilateral diaphragmatic paralysis NEUROLOGY Lin, P. T., Andersson, P. B., Distad, B. J., Barohn, R. J., Cho, S. C., So, Y. T., Katz, J. S. 2005; 65 (9): 1499-1501

    Abstract

    The authors report four patients with a syndrome of painless bilateral isolated phrenic neuropathy. Electrophysiologic testing demonstrated active denervation restricted to the diaphragm. Long-term recovery was poor. The authors conclude that bilateral isolated phrenic neuropathy is a cause of painless diaphragmatic paralysis distinguishable from immune brachial plexus neuropathy and other neuromuscular disorders with similar clinical presentation.

    View details for Web of Science ID 000233114100037

    View details for PubMedID 16275847

  • Use of serum prolactin in diagnosing epileptic seizures - Report of the therapeutics and technology assessment subcommittee of the American academy of neurology NEUROLOGY Chen, D. K., So, Y. T., Fisher, R. S. 2005; 65 (5): 668-675

    Abstract

    The purpose of this article is to review the use of serum prolactin assay in epileptic seizure diagnosis.The authors identified relevant studies in multiple databases and reference lists. Studies that met inclusion criteria were summarized and rated for quality of evidence, and the results were analyzed and pooled where appropriate.Most studies used a serum prolactin of at least twice baseline value as abnormal. For the differentiation of epileptic seizures from psychogenic nonepileptic seizures, one Class I and seven Class II studies showed that elevated serum prolactin was highly predictive of either generalized tonic-clonic or complex partial seizures. Pooled sensitivity was higher for generalized tonic-clonic seizures (60.0%) than for complex partial seizures (46.1%), while the pooled specificity was similar for both (approximately 96%). Data were insufficient to establish validity for simple partial seizures. Two Class II studies were consistent in showing prolactin elevation after tilt-test-induced syncope. Inconclusive data exist regarding the value of serum prolactin following status epilepticus, repetitive seizures, and neonatal seizures.Elevated serum prolactin assay, when measured in the appropriate clinical setting at 10 to 20 minutes after a suspected event, is a useful adjunct for the differentiation of generalized tonic-clonic or complex partial seizure from psychogenic nonepileptic seizure among adults and older children (Level B). Serum prolactin assay does not distinguish epileptic seizures from syncope (Level B). The use of serum PRL assay has not been established in the evaluation of status epilepticus, repetitive seizures, and neonatal seizures (Level U).

    View details for Web of Science ID 000231821300004

    View details for PubMedID 16157897

  • Clinical utility of electrodiagnostic consultation in suspected polyneuropathy MUSCLE & NERVE Cho, S. C., Siao-Tick-Chong, P., So, Y. T. 2004; 30 (5): 659-662

    Abstract

    Although paresthesias of the distal lower limbs are characteristic features of polyneuropathy, they may also herald the presence of a focal neuropathy, polyradiculopathy, or myelopathy. Electromyography and nerve conduction studies (EMG/NCS) are widely used in the evaluation of such symptoms, but their utility has not been subjected to vigorous scrutiny. We investigated the clinical impact of the electrodiagnostic consultation in assessing suspected polyneuropathy. When compared with the clinical impression, the result of the electrodiagnostic consultation was confirmatory in only 39% of all patients, and changed the diagnosis or uncovered an additional diagnosis in 43%. An alternative diagnosis was likely when either weakness was present (75%) or the Achilles stretch reflex was preserved (48%). These data support the use of EMG/NCS in the diagnostic evaluation of patients presenting with distal paresthesias, especially in those with preserved Achilles reflexes or motor deficits.

    View details for DOI 10.1002/mus.20119

    View details for Web of Science ID 000224821200013

    View details for PubMedID 15389656

  • Phenotypic variability associated with Arg26Gln mutation in caveolin3 MUSCLE & NERVE Fee, D. B., So, Y. T., Barraza, C., Figueroa, K. P., Pulst, S. M. 2004; 30 (3): 375-378

    Abstract

    Caveolin3 (CAV3) is a protein associated with dystrophin, dystrophin-associated glycoproteins, and dysferlin. Mutations in the CAV3 gene result in certain autosomal-dominant inherited diseases, namely, rippling muscle disease (RMD), limb-girdle muscular dystrophy type 1C (LGMD1C), distal myopathy, and hyperCKemia. In this report we show that a previously reported family with RMD has a mutation in the CAV3 gene. Affected individuals had either a characteristic RMD phenotype, a combination of RMD and LGMD1C phenotypes, or a LGMD1C phenotype, but one mutation carrier was asymptomatic at age 86 years. This phenotypic variability associated with mutations in CAV3 has been reported previously but only in a few families. It is important to remember the significant phenotypic variability associated with CAV3 mutations when counseling families with these mutations. These observations also suggest the presence of factors independent of the CAV3 gene locus that modify phenotype.

    View details for DOI 10.1002/mus.20092

    View details for Web of Science ID 000223529500014

    View details for PubMedID 15318349

  • Lamotrigine for HIV-associated painful sensory neuropathies - A placebo-controlled trial NEUROLOGY Simpson, D. M., McArthur, J. C., Olney, R., Clifford, D., So, Y., Ross, D., Baird, B. J., Barrett, P., Hammer, A. E. 2003; 60 (9): 1508-1514

    Abstract

    To evaluate the efficacy and tolerability of lamotrigine (LTG) for the treatment of pain in HIV-associated sensory neuropathies.In a randomized, double-blind study, patients with HIV-associated distal sensory polyneuropathy (DSP) received LTG or placebo during a 7-week dose escalation phase followed by a 4-week maintenance phase. Randomization was stratified according to whether or not patients were currently using neurotoxic antiretroviral therapy (ART).The number of patients randomized was 92 (62 LTG, 30 placebo) in the stratum receiving neurotoxic ART and 135 (88 LTG, 47 placebo) in the stratum not receiving neurotoxic ART. Mean change from baseline in Gracely Pain Scale score for average pain was not different between LTG and placebo at the end of the maintenance phase in either stratum, but the slope of the change in Gracely Pain Scale score for average pain reflected greater improvement with LTG than with placebo in the stratum receiving neurotoxic ART (p = 0.004), as did the mean change from baseline scores on the Visual Analogue Scale for Pain Intensity and the McGill Pain Assessment Scale and patient and clinician ratings of global impression of change in pain (p

    View details for Web of Science ID 000182754100022

    View details for PubMedID 12743240

  • Quantitative sensory testing - Report of the therapeutics and technology assessment subcommittee of the American Academy of Neurology NEUROLOGY Shy, M. E., Frohman, E. M., So, Y. T., Arezzo, J. C., Cornblath, D. R., Giuliani, M. J., Kincaid, J. C., Ochoa, J. L., Parry, G. J., Weimer, L. H. 2003; 60 (6): 898-904

    Abstract

    This assessment evaluates the clinical utility, efficacy, and safety of quantitative sensory testing (QST).By searching MEDLINE, Current Contents, and their personal files, the authors identified 350 articles. Selected articles utilized computer operated threshold systems, manually operated threshold systems, and electrical threshold devices. The authors evaluated the use of normal values and the degree of reproducibility between the same and different systems. Articles were rated using a standard classification of evidence scheme.Because of differences between systems, normal values from one system cannot be transposed to others. Reproducibility of results was also an important concern, and there is no consensus on how it should be defined. The authors identified no adequately powered class I studies demonstrating the effectiveness of QST in evaluating any particular disorder. A number of class II and III studies demonstrated that QST is probably or possibly useful in identifying small or large fiber sensory abnormalities in patients with diabetic neuropathy, small fiber neuropathies, uremic neuropathies, and demyelinating neuropathy.QST is a potentially useful tool for measuring sensory impairment for clinical and research studies. However, QST results should not be the sole criteria used to diagnose pathology. Because malingering and other nonorganic factors can influence the test results, QST is not currently useful for the purpose of resolving medicolegal matters. Well-designed studies comparing different QST devices and methodologies are needed and should include patients with abnormalities detected solely by QST.

    View details for Web of Science ID 000182948600004

    View details for PubMedID 12654951

  • An approach to critically ill patients in coma WESTERN JOURNAL OF MEDICINE Liao, Y. J., So, Y. T. 2002; 176 (3): 184-187

    View details for Web of Science ID 000179442400012

    View details for PubMedID 12016243

  • Rippling muscle disease: Evidence for phenotypic and genetic heterogeneity MUSCLE & NERVE So, Y. T., Zu, L., Barraza, C., Figueroa, K. P., Pulst, S. M. 2001; 24 (3): 340-344

    Abstract

    We describe the clinical features of a family with rippling muscle disease. Muscle stiffness and myalgia were the most prominent symptoms. Muscle rippling, although distinctive, was present in only 6 of the 11 affected family members, whereas persistent muscle contraction to muscle percussion was present in all affected adults. Although this persistent contraction resembled percussion myotonia, it was electrically silent and is therefore more aptly called "percussion contracture." We also observed two clinical features not emphasized in previously reported kindreds: mild but asymptomatic weakness of face or proximal muscles was present in 5 of 11 affected members, and 5 individuals also complained of toe walking after a prolonged period of inactivity, reflecting the disproportionate involvement of the calf muscles. The pedigree suggested autosomal dominant inheritance. Our linkage analysis excluded the region on chromosome 1q identified in a previous linkage study.

    View details for Web of Science ID 000167117100004

    View details for PubMedID 11353417

  • Sensory nerve conduction study of the mental nerve MUSCLE & NERVE Deeb, G. R., Dierks, E., So, Y. T. 2000; 23 (7): 1121-1124

    Abstract

    We describe a technique for sensory nerve conduction study of the mental nerve. A monopolar recording needle is placed near the mandibular foramen using the same approach as that for routine inferior alveolar nerve block in dentistry, and a surface reference electrode is positioned over the ipsilateral mastoid process. Sensory nerve action potentials to stimulation of the mental nerve at the chin can be reliably recorded orthodromically in normal healthy subjects. The method is simple and well tolerated and provides a useful means to evaluate mental nerve function electrophysiologically.

    View details for Web of Science ID 000087966000017

    View details for PubMedID 10883009

  • Electrodiagnostic features of hereditary neuropathy with liability to pressure palsies NEUROLOGY Andersson, P. B., Yuen, E., Parko, K., So, Y. T. 2000; 54 (1): 40-44

    Abstract

    Because diagnosis of hereditary neuropathy with liability to pressure palsies (HNPP) frequently is missed or delayed, we looked for electrodiagnostic features that raise suspicion of the disorder by making comparisons with two more common diseases that mimic it electrophysiologically: chronic inflammatory demyelinating polyneuropathy (CIDP) and diabetic polyneuropathy.A retrospective review of the neuromuscular laboratory database was performed.Nine HNPP subjects, 22 with CIDP and 49 with diabetic polyneuropathy. Of all the HNPP nerves studied, abnormally slow sensory nerve conduction velocity (SNCV) was found in 93%, prolonged distal motor latencies (DML) in 78%, slow motor nerve conduction velocity in 31%, and prolonged F-wave latencies in 90%. Mean SNCV for HNPP was 85.6%+/-10.6% of the lower limit of normal and significantly slower than for CIDP (114.3%+/-20.1%; p<0.0001) or diabetes (108.1%+/-14.8%; p<0.0001). Excluding the carpal tunnel site from the analysis did not alter this observation: Mean DML were more prolonged in HNPP, even without median nerve data in the analysis (118.5%+/-31.0% of the upper limit of normal), than in CIDP (103.2%+/-31.6%; p<0.05) or diabetes (86.3%+/-18.3%; p<0.0001). Mean HNPP motor nerve conduction velocity was within normal limits.According to findings, hereditary neuropathy with liability to pressure palsies (HNPP) has a distinctive background polyneuropathy independent of superimposed entrapment neuropathy. It is characterized by diffuse sensory nerve conduction velocity (SNCV) slowing and prolongation of distal motor latencies with relatively infrequent and minor reduction of motor nerve conduction velocities. This indicates disproportionate distal conduction slowing in the disorder.

    View details for Web of Science ID 000084727900009

    View details for PubMedID 10636123

  • Sciatic neuropathy NEUROLOGIC CLINICS Yuen, E. C., So, Y. T. 1999; 17 (3): 617-?

    Abstract

    Injuries to the sciatic nerve cause neurologic deficits in the peroneal and tibial nerve distributions. Interestingly, most injuries result in more severe deficits to the peroneal division compared to the tibial division. Thus, it can sometimes be difficult to distinguish sciatic neuropathy from peroneal neuropathy. The long course of the sciatic nerve leaves it vulnerable to nerve injury from a variety of causes. Most sciatic neuropathies are acute in onset, such as from hip arthroplasty and hip fracture or dislocation, but some occur from prolonged compression, such as during coma. Entrapment of the sciatic nerve by mass lesions or by the piriformis muscle is relatively rare.

    View details for Web of Science ID 000081653100012

    View details for PubMedID 10393756

  • Effect of keyboard keyswitch design on hand pain JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL MEDICINE Rempel, D., Tittiranonda, P., Burastero, S., Hudes, M., So, Y. 1999; 41 (2): 111-119

    Abstract

    This randomized clinical trial evaluated the effects of keyboard keyswitch design on computer users with hand paresthesias. Twenty computer users were matched and randomly assigned to keyboard A (n = 10) or B (n = 10). The keyboards were of conventional layout and differed in keyswitch design. Various outcome measures were assessed during the 12 weeks of use. Subjects assigned keyboard A experienced a decrease in hand pain between weeks 6 and 12 when compared with keyboard B subjects (P = 0.05) and demonstrated an improvement in the Phalen test time (right hand, P = 0.006; left hand, P = 0.06). Keyboard assignment had no significant effect on change in hand function or median nerve latency. We conclude that use of keyboard A for 12 weeks led to a reduction in hand pain and an improved physical examination finding when compared with keyboard B. There was no corresponding improvement in hand function or median nerve latency.

    View details for Web of Science ID 000078655300006

    View details for PubMedID 10029956

  • Guidelines in electrodiagnostic medicine. Practice parameter for needle electromyographic evaluation of patients with suspected cervical radiculopathy. Muscle & nerve. Supplement So, Y. T. 1999; 8: S209-21

    Abstract

    Cervical radiculopathy is a common cause of morbidity. Its management often requires clinical, electrodiagnostic, and radiological evaluation, and its treatment may include surgery. Based on a critical review of the literature, electrodiagnostic evaluation is found to be moderately sensitive and highly specific in establishing a diagnosis of cervical radiculopathy. This document defines teh guidelines and options for the electrodiagnostic medicine consultation of patients with suspected cervical radiculopathy.

    View details for PubMedID 16921635

  • Natural killer cell leukemia as a cause of peripheral neuropathy and meningitis: Case report NEUROLOGY Lackowski, D., Koberda, J. L., DeLoughery, T. G., So, Y. 1998; 51 (2): 640-641

    View details for Web of Science ID 000075387400072

    View details for PubMedID 9710063

  • Modeling the acute neurotoxicity of styrene JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL MEDICINE Pierce, C. H., Pecker, C. E., Tozer, T. N., Owen, D. J., So, Y. 1998; 40 (3): 230-240

    Abstract

    Styrene is a widely used industrial solvent associated with acute neurotoxicity. To investigate the relationships between exposure, blood concentrations, and the appearance of neurotoxic effects, four healthy males were exposed to styrene concentrations of 5-200 ppm in four different exposure-time profiles. A digit recognition test and P300 event-related evoked potential were used to measure neurologic function. A physiologically based kinetic (PBK) model generated close predictions of measured styrene blood concentrations, in the range of 0.01-12 mg/L, from this and 21 previous studies. Simulated peak brain concentration, durationXaverage exposure, and peak exposure level were predictive of toxicity. Central nervous system effects were expected at a blood concentration near 2.4 mg/L. A standard of 20 ppm was expected to protect styrene-exposed workers from acute central nervous system toxicity under light work conditions.

    View details for Web of Science ID 000072467000005

    View details for PubMedID 9531094

  • Effects of forearm pronation/supination on carpal tunnel pressure. journal of hand surgery Rempel, D., Bach, J. M., Gordon, L., So, Y. 1998; 23 (1): 38-42

    Abstract

    The effects of forearm rotation and metacarpophalangeal (MP) flexion on carpal tunnel pressure were investigated in 17 healthy adults who had no evidence of carpal tunnel syndrome (CTS). Pressure was continuously recorded with a saline-filled catheter inserted into the carpal tunnel and connected to a pressure transducer while test subjects slowly rotated the forearm from full pronation to full supination. Forearm rotation was repeated with MP flexion of 0 degrees, 45 degrees, and 90 degrees. Both forearm rotation and MP flexion, and their interaction term, significantly affected carpal tunnel pressure and accounted for most of the variability in the data. Highest mean pressures (55 mmHg) were recorded in full supination and 90 degrees MP flexion and lowest pressures (12 mmHg) were recorded at 45 degrees pronation and 45 degrees MP flexion. These data may be useful in the design of tasks and hand tools in the management and prevention of CTS.

    View details for PubMedID 9523952

  • Peptide T in the treatment of painful distal neuropathy associated with AIDS: Results of a placebo-controlled trial NEUROLOGY Simpson, D. M., Dorfman, D., Olney, R. K., McKinley, G., Dobkin, J., So, Y., Berger, J., FERDON, M. B., Friedman, B. 1996; 47 (5): 1254-1259

    Abstract

    To assess the safety and efficacy of Peptide T in the treatment of painful distal symmetrical polyneuropathy (DSP) associated with human immunodeficiency virus (HIV) infection.Painful DSP is a frequent complication of HIV infection, although its etiology and optimal treatment are unknown. Peptide T (D-(alpha 1)-Peptide T-amide) has been found in phase I trials and anecdotal reports to relieve neuropathic pain in AIDS patients.In this multicentered, double-blind, randomized study, subjects received intranasal Peptide T 6 mg/day or placebo for 12 weeks. The primary outcome measure was change in the modified Gracely pain score. Secondary efficacy variables were results of neurologic examination, neuropsychological and electrophysiologic studies, global evaluation, and CD4 lymphocyte counts.Of 81 evaluable subjects, 40 received Peptide T and 41 received placebo. The change in pain scores was not significantly different (p = 0.32) in the Peptide T group (-0.24) as compared to placebo (-0.39). Group comparisons were not significantly different for change in any clinical examination or neuropsychologic measure, sural nerve amplitude or conduction velocity, or CD4 lymphocyte count. No significant drug-related adverse effects occurred in either group.Intranasal Peptide T is safe but ineffective in the treatment of painful DSP associated with AIDS.

    View details for Web of Science ID A1996VR42500024

    View details for PubMedID 8909439

  • The association of systemic lupus erythematosus and Lambert-Eaton myasthenic syndrome JOURNAL OF RHEUMATOLOGY Deodhar, A., Norden, J., So, Y., Bennett, R. 1996; 23 (7): 1292-1294

    Abstract

    The association of systemic lupus erythematosus (SLE) and myasthenia gravis is well known. However, the association between SLE and Lambert-Eaton myasthenic syndrome (LEMS) is described in only 2 cases. We describe the case of a 31-year-old woman with SLE who presented with severe, predominantly proximal muscle weakness of subacute onset. The diagnosis of LEMS was based on her distinctive clinical and electrophysiological findings. She was treated successfully with plasmapheresis and oral prednisone. She remains in remission 6 months after this episode.

    View details for Web of Science ID A1996UV68100032

    View details for PubMedID 8823710

  • Temperature effects on vibrotactile sensitivity threshold measurements: implications for carpal tunnel screening tests. journal of hand surgery Klinenberg, E., So, Y., Rempel, D. 1996; 21 (1): 132-137

    Abstract

    This study examines the effect of skin temperature on fingertip vibrotactile sensitivity measurements and the resulting implications for carpal tunnel syndrome screening tests. Twenty subjects (11 men, 9 women) were tested for fingertip vibrotactile thresholds using the method of limits at four different frequencies (31.5, 125, 250, and 500 Hz) and six temperature categories (17 degrees-20 degrees C, 20 degrees-23 degrees C, 23 degrees-26 degrees C, 26 degrees-29 degrees C, 29 degrees-32 degrees C, 32 degrees-35 degrees C). Vibrotactile sensitivity thresholds increased with decreasing fingertip skin temperature. Furthermore, the relationship was a function of vibration frequency. Higher frequencies were more affected by temperature than lower frequencies, with significant effects beginning at 29 degrees C. These temperature-related effects may lead to possible false positive results in screening for carpal tunnel syndrome or other neuropathies. To minimize potential temperature-induced misclassification errors during these screening tests, fingertip skin temperature should be recorded before measurement and probably maintained above 29 degrees C during the measurement.

    View details for PubMedID 8775208

  • POSITION OF THE WRIST ASSOCIATED WITH THE LOWEST CARPAL-TUNNEL PRESSURE - IMPLICATIONS FOR SPLINT DESIGN JOURNAL OF BONE AND JOINT SURGERY-AMERICAN VOLUME WEISS, N. D., Gordon, L., Bloom, T., So, Y., Rempel, D. M. 1995; 77A (11): 1695-1699

    Abstract

    Increased carpal-tunnel pressure has been implicated in the pathophysiology of carpal tunnel syndrome, but it is not known whether splints that immobilize the wrist in a functional position of extension minimize carpal tunnel pressure. To determine the position of the wrist that results in the lowest carpal-tunnel pressure, twenty control subjects and four patients who had carpal tunnel syndrome were evaluated with use of a new, dynamic method that continuously measures carpal tunnel pressure throughout the range of motion of the wrist. The pressure was measured by means of a pressure transducer connected to a flexible catheter that had been inserted into the carpal canal. The position of the wrist was measured simultaneously with use of a two-axis electrogoniometer. Aided by a computer monitor that displayed a moving line of real-time carpal-tunnel pressure, each subject was instructed to move the wrist throughout the range of motion and to adjust it to the position that corresponded to the lowest carpal-tunnel pressure. For the control subjects, the lowest carpal-tunnel pressure averaged 8 +/- 4 millimeters of mercury (1.07 +/- 0.53 kilopascals), and the average position of the wrist associated with the lowest pressure was 2 +/- 9 degrees of extension and 2 +/- 6 degrees of ulnar deviation.(ABSTRACT TRUNCATED AT 250 WORDS)

    View details for Web of Science ID A1995TG26600008

  • THE ELECTROPHYSIOLOGIC FEATURES OF SCIATIC NEUROPATHY IN 100 PATIENTS MUSCLE & NERVE Yuen, E. C., So, Y. T., Olney, R. K. 1995; 18 (4): 414-420

    Abstract

    We reviewed the electrophysiologic data of 100 consecutive patients with sciatic neuropathy in order to better understand this disorder. Most patients (93%) had electrodiagnostic signs of significant axonal loss. Seven patients had predominantly signs of demyelination; 6 were due to compression and 1 was idiopathic. The peroneal division was more severely affected than the tibial division in 64% of patients. Tibialis anterior EMGs were abnormal in 92%, and the EDB CMAP was low in amplitude or absent in 80%. CMAP and SNAP amplitudes and EMGs were all normal in the tibial division in 12%. In contrast, the tibial division was more severely affected in only 8 patients. Of those, 5 were due to thigh trauma (gunshot wounds or femur fracture), 2 from gunshot wounds to the hip, and the other was chronic and idiopathic. Sciatic neuropathies are commonly, but not always, axonal loss lesions that affect the peroneal greater than tibial division.

    View details for Web of Science ID A1995QN27200007

    View details for PubMedID 7715627

  • INCIDENCE PROPORTION OF AND RISK-FACTORS FOR AIDS PATIENTS DIAGNOSED WITH HIV DEMENTIA, CENTRAL-NERVOUS-SYSTEM TOXOPLASMOSIS, AND CRYPTOCOCCAL MENINGITIS JOURNAL OF ACQUIRED IMMUNE DEFICIENCY SYNDROMES AND HUMAN RETROVIROLOGY Wang, F., So, Y., Vittinghoff, E., MALANI, H., Reingold, A., Lewis, E., Giordano, J., Janssen, R. 1995; 8 (1): 75-82

    Abstract

    We undertook this study to determine the incidence proportion of and risk factors for AIDS patients diagnosed with human immunodeficiency virus (HIV) dementia, central nervous system (CNS) toxoplasmosis, and cryptococcal meningitis. A historical cohort of 487 consecutive inpatients with AIDS treated by San Francisco General Hospital inpatient and outpatient services entered the study. We abstracted all available records for demographic information, diagnoses, and dates of death and estimated the incidence proportion of AIDS patients diagnosed with major CNS complications using the Kaplan-Meier method. We used the Cox proportional hazards model to analyze the effect of demographic factors on the hazard (risk per unit time) of diagnosis with these CNS conditions. The estimated incidence proportion of patients diagnosed with HIV dementia within 1 and 2 years of AIDS diagnosis increased from 0.10 to 0.18. Corresponding proportions were 0.10 and 0.19 for CNS toxoplasmosis and 0.10 and 0.14 for cryptococcal meningitis. Only HIV dementia was independently associated with increasing age at AIDS diagnosis (relative hazard [RH] of 2.75 for ages 41-50 [95% confidence interval, 1.08-6.98]; RH of 4.73 for ages > 50 [95% confidence interval, 1.41-15.87]) and with injection drug use (RH of 2.03; 95% confidence interval, 1.19-3.47). HIV dementia, CNS toxoplasmosis, and cryptococcal meningitis are about equally common complications in patients with AIDS, but only HIV dementia is associated with increasing age at AIDS diagnosis and injection drug use.

    View details for Web of Science ID A1995QA52600012

    View details for PubMedID 8548350

  • SCIATIC NEUROPATHY - CLINICAL AND PROGNOSTIC FEATURES IN 73 PATIENTS NEUROLOGY Yuen, E. C., Olney, R. K., So, Y. T. 1994; 44 (9): 1669-1674

    Abstract

    We examined the clinical features of patients with sciatic neuropathy and the factors that influence prognosis. Of 92 consecutive patients referred for EMG evaluation of sciatic neuropathy, 73 fulfilled strict inclusion and exclusion criteria and had adequate clinical and electrophysiologic information. The etiologies included hip arthroplasty (21.9%), acute external compression (13.7%), infarction (9.6%), gunshot wound (9.6%), hip fracture/dislocation (9.6%), femur fracture (4.1%), contusion (4.1%), and uncertain (16.4%). We used life table analysis to determine outcome and to identify prognostic factors in patients with acute or subacute onset. Moderate or better recovery (improvement to grade 2 or by two of six clinical grades) occurred in most patients (30% by 1 year, 50% by 2 years, 75% by 3 years). A subgroup experienced excellent improvement (by three of six grades, or to grade 2) less frequently (33% by 2 and 3 years). Of the nine factors tested, two predicted an earlier or better recovery: a recordable compound muscle action potential of the extensor digitorum brevis (p < 0.025), and an initial absence of paralysis of muscles controlling ankle plantar flexion and dorsiflexion (p < 0.05). Thus, good but incomplete recovery occurs over 2 to 3 years in most patients with sciatic neuropathy, particularly in those without severe motor axonal loss.

    View details for Web of Science ID A1994PG39000022

    View details for PubMedID 7936294

  • DEEP PREPIRIFORM CORTEX MODULATES KAINATE-INDUCED HIPPOCAMPAL INJURY NEUROSCIENCE Shimosaka, S., So, Y. T., Simon, R. P. 1994; 61 (4): 817-822

    Abstract

    As seizure propagation within limbic structures is mediated in part by a small area of deep prepiriform cortex (area tempestas), we investigated the role of area tempestas in modulating hippocampal injury induced by systemic kainate administration. Injury was quantitated by counting the numbers of neurons that stained for the 72,000 mol. wt heat shock protein and with acid-fuchsin dye. Status epilepticus induced these markers of neuronal injury in the CA1 and CA3a regions of the hippocampus, thalamus, piriform cortex and the amygdaloid complex. Microinjection of 2-amino-7-phosphonoheptanoic acid, a competitive antagonist of the N-methyl-D-aspartate subclass of the glutamate receptor, into area tempestas prior to systemic administration of kainate attenuated both heat shock protein induction and acid-fuchsin labeling in CA1 and CA3a pyramidal neurons without reducing the duration of electrographic seizures. Injections of bicuculline, a GABA antagonist, into area tempestas produced hippocampal damage when given with subcytotoxic doses of intravenous kainate. Thus, area tempestas may be a uniquely sensitive anatomical structure involved not just in seizure propagation but also in modulating the extent and pattern of damage induced in hippocampal neurons as a result of prolonged, systemically induced seizures. These effects are due in part to excitatory and inhibitory projections to neurons in area tempestas.

    View details for Web of Science ID A1994PE79700011

    View details for PubMedID 7838380

  • ACUTE LUMBOSACRAL POLYRADICULOPATHY IN ACQUIRED-IMMUNODEFICIENCY-SYNDROME - EXPERIENCE IN 23 PATIENTS ANNALS OF NEUROLOGY So, Y. T., Olney, R. K. 1994; 35 (1): 53-58

    Abstract

    We reviewed our experience in 23 patients with acquired immunodeficiency syndrome (AIDS) who had acute lumbosacral polyradiculopathy. The patients developed a distinctive syndrome of rapidly progressive flaccid paraparesis and areflexia that was frequently associated with sphincter disturbances. Persuasive laboratory evidence of a cytomegalovirus polyradiculopathy (polymorphonuclear pleocytosis or confirmatory cerebrospinal fluid culture) was found in 15 of the 23 patients. Treatment with ganciclovir in these patients led to clinical stabilization, although worsening during the first 2 weeks of treatment was common. Most patients with cytomegalovirus polyradiculopathy had severe residual deficits. Metastasis from systemic lymphoma accounted for the polyradiculopathy in 2 other patients. A more benign syndrome was identified in the remaining 6 patients. They generally had slower clinical progression and less severe neurological deficits at their nadir than did patients with cytomegalovirus polyradiculopathy. Unlike patients with cytomegalovirus infection, their cerebrospinal fluid showed a predominantly mononuclear pleocytosis. Moreover, spontaneous improvement without treatment was common. Our experience together with the published experience of others suggests that the acute lumbosacral polyradiculopathy in AIDS is a clinical syndrome with different etiologies and variable clinical outcome. Recognition of this heterogeneity is necessary for the management of individual patients, as well as the interpretation of treatment results.

    View details for Web of Science ID A1994MQ91100007

    View details for PubMedID 8285593

  • LITERATURE-REVIEW OF THE USEFULNESS OF NERVE-CONDUCTION STUDIES AND ELECTROMYOGRAPHY FOR THE EVALUATION OF PATIENTS WITH CARPAL-TUNNEL SYNDROME MUSCLE & NERVE Jablecki, C. K., Andary, M. T., So, Y. T., Wilkins, D. E., Williams, F. H., Ball, R. D., Cherington, M., Fisher, M. A., Phillips, L. H., Tulloch, J. W., Turk, M. A., WIECHERS, D. O., Wilbourn, A. J., YSLA, R. G. 1993; 16 (12): 1392-1414

    Abstract

    The sensitivity and specificity of nerve conduction studies (NCS's) and electromyography (EMG) for the diagnosis of carpal tunnel syndrome (CTS) were evaluated by a critical review of the literature. With a search of the medical literature in English through May 1991, 165 articles were identified and reviewed on the basis of six criteria of scientific methodology. The findings of 11 articles that met all six criteria and the results of 48 additional studies that met four or five criteria are presented. We concluded that median sensory and motor NCS's are valid and reproducible clinical laboratory studies that confirm a clinical diagnosis of CTS with a high degree of sensitivity and specificity. Clinical practice recommendations are made based on a comparison of the sensitivities of the several different median nerve conduction study (NCS) techniques.

    View details for Web of Science ID A1993MH86900017

  • PRACTICE PARAMETER FOR ELECTRODIAGNOSTIC STUDIES IN CARPAL-TUNNEL SYNDROME NEUROLOGY Rosenberg, J. H., Alter, M., Daube, J. R., Franklin, G., Frishberg, B. M., Greenberg, M. K., Lanska, D. J., Paulson, G., PEARL, R. A., Sila, C. A., Jablecki, C. K., Andary, M. T., Ball, R. D., Cherington, M., Fisher, M. A., Phillips, L. H., So, Y. T., TULLOCH, W., Turk, M. A., WIECHERS, D. O., Wilbourn, A. J., Williams, F. H., YSLA, R. G., Granger, C. V., DeLisa, J. A., LaBan, M. M., Lieberman, J. S., TOMSKI, M. A., Turk, M. A. 1993; 43 (11): 2404-2405
  • CLINICAL AND RADIOGRAPHIC FINDINGS IN DISSEMINATED TUBERCULOSIS OF THE BRAIN NEUROLOGY Eide, F. F., Gean, A. D., So, Y. T. 1993; 43 (7): 1427-1429

    Abstract

    We report clinical and radiographic findings in a patient with disseminated tuberculosis (TB) of the brain. A Burmese man developed a left hemiparesis and mild cognitive difficulty 1 month into therapy for miliary TB. A head MRI showed numerous (> 100) contrast-enhancing supratentorial and infratentorial lesions. Following 9 months of treatment with isoniazid, ethambutol, rifampin, and pyrazinamide, most lesions resolved; however, one cortical tuberculoma enlarged significantly. The patient was continued on isoniazid and rifampin, with radiographic resolution of the tuberculoma 4 months later.

    View details for Web of Science ID A1993LM10400033

    View details for PubMedID 8018121

  • THE P300 EVENT-RELATED POTENTIAL - THE EFFECTS OF SLEEP-DEPRIVATION JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL MEDICINE Morris, A. M., YUEN, S., Lee, K. A., LASH, A. A., BECKER, C. E. 1992; 34 (12): 1143-1152

    Abstract

    We monitored 15 healthy young adults during 18 hours of sleep deprivation. Subjects were repeatedly tested on measures of the P300 (P3) event-related potential, reaction time, body temperature, and a subjective rating of fatigue. Statistically significant decreases in P3 amplitude (P < or = .01) and increases in P3 latency (P < or = .0001) were found during sleep deprivation. These changes correlated with body temperature and fatigue and were not due to circadian variation. Reaction time did not show a significant change over time. We conclude that the P3 potential is a more sensitive cognitive measure of sleep deprivation than reaction time, a measure commonly used in previous studies. We provide a review of the literature on the P3 and recommend the use of the P3 as a marker to examine sleep deprivation in health professionals.

    View details for Web of Science ID A1992KB89400001

    View details for PubMedID 1464782

  • DISTRIBUTION OF HSP72 INDUCTION AND NEURONAL DEATH FOLLOWING LIMBIC SEIZURES NEUROSCIENCE LETTERS Shimosaka, S., So, Y. T., Simon, R. P. 1992; 138 (2): 202-206

    Abstract

    A small area of deep prepiriform cortex is uniquely susceptible to convulsant and anticonvulsant drugs in the rat. We have studied the pattern of expression of the non-constitutive stress protein (HSP72) following seizures induced by unilateral microinjection of bicuculline into this area. HSP was seen first in ipsilateral dorsal medial thalamus, amygdala and associated piriform cortex, and with more sustained seizures was seen bilaterally in these structures as well as in other projection sites. Neuronal cell death, as assessed by acid-fuchsin staining, occurred in the same brain regions. Frank necrosis was found in the ipsilateral piriform cortex with prolonged seizures. Behaviorally, the seizures induced are characteristic of involvement of the limbic system and, therefore, may be a model of human complex partial seizures.

    View details for Web of Science ID A1992HV12500002

    View details for PubMedID 1376869

  • ACUTE PARALYTIC POLIOMYELITIS MUSCLE & NERVE So, Y. T., Olney, R. K. 1991; 14 (12): 1159-1164

    Abstract

    A 56-year-old man with acute paralytic poliomyelitis is described. The illness started with fever and diarrhea after an overseas trip, and an enterovirus other than poliovirus was isolated from the patient's stool. The onset of weakness was rapid and asymmetric, with primary involvement of the lower extremities. Nerve conduction studies revealed low amplitude motor responses after the first week, with normal results for sensory studies. Serial electromyographic studies were performed, documenting acute denervation followed later by reinnervation in the distribution of multiple segments. The clinical and electrodiagnostic features of acute poliomyelitis are reviewed.

    View details for Web of Science ID A1991GU24800001

  • CLINICAL AND ELECTRODIAGNOSTIC FEATURES OF X-LINKED RECESSIVE BULBOSPINAL NEURONOPATHY NEUROLOGY Olney, R. K., Aminoff, M. J., So, Y. T. 1991; 41 (6): 823-828

    Abstract

    We describe four men from two kinships affected with X-linked recessive bulbospinal neuronopathy, and one sporadic case. All developed postural tremor, weakness, and fasciculations, with onset from age 25 to 39 years. Weakness began in the pelvic girdle or hands, with dysphagia or dysarthria occurring years later in two. Sensory symptoms were present in only one, who also had diabetes mellitus. In contrast, sural nerve action potentials were small or absent in all. Needle EMG showed widespread chronic partial denervation with reinnervation. The characteristic twitching of the chin produced by pursing of the lips consisted of repetitive or grouped motor unit discharges, rather than fasciculations. Broader awareness of the distinctive features of bulbospinal neuronopathy will probably increase the frequency of its recognition. Diagnosis is important for purposes of providing a prognosis for affected men and genetic counseling for affected families.

    View details for Web of Science ID A1991FR07500017

    View details for PubMedID 2046924

  • NEUROTOXIC EFFECTS OF METHYLENE-CHLORIDE - ARE THEY LONG LASTING IN HUMANS BRITISH JOURNAL OF INDUSTRIAL MEDICINE LASH, A. A., BECKER, C. E., So, Y., Shore, M. 1991; 48 (6): 418-426

    Abstract

    The neurotoxicity of methylene chloride (MC) is of special interest because of its acute effects on the central nervous system (CNS) and its metabolic conversion to carbon monoxide. A cohort study of retired airline mechanics was conducted to examine the hypothesis that long term exposure to MC results in lasting effects on the CNS. Retirees were studied to eliminate effects of current occupational exposures. The total retiree population (n = 1758) was surveyed to identify mechanics who met specific occupational, demographic, and medical criteria. A group of eligible retirees having long term exposure to MC and another group with low probability of exposure to solvents were given a comprehensive battery of physiological and psychological tests. The exposure groups were similar for all potential confounders that were measured. No statistically significant differences between groups were detected on outcome measures, although subtle differences in attention and memory were identified. Thus no firm evidence was found to support the hypothesis of lasting CNS effects in retired mechanics with long term exposure to MC.

    View details for Web of Science ID A1991FR42600011

    View details for PubMedID 2064980

  • A COMPARISON OF THERMOGRAPHY AND ELECTROMYOGRAPHY IN THE DIAGNOSIS OF CERVICAL RADICULOPATHY MUSCLE & NERVE So, Y. T., Olney, R. K., Aminoff, M. J. 1990; 13 (11): 1032-1036

    Abstract

    We studied 20 asymptomatic control subjects and 14 patients with clinically unequivocal cervical radiculopathy to compare the diagnostic value of thermography with that of electromyography. We measured the average skin temperature of designated regions over the neck, shoulder, and upper extremities. We then compared the temperature between corresponding regions of the two limbs, and between fingers innervated by different roots in the same hand. Thermography was abnormal in 6 patients (43%), whereas electromyography was abnormal in 10 (71%). Thermographic abnormalities were seen only in the hands and fingers, and the pattern did not follow the dermatome of the clinically involved cervical root. When compared to electromyography, thermography provided no additional diagnostic information. Thus, thermography does not have an established role in the evaluation of patients with cervical radiculopathy.

    View details for Web of Science ID A1990ED87300005

    View details for PubMedID 2172814

  • A COMPARISON OF MAGNETIC AND ELECTRICAL-STIMULATION OF PERIPHERAL-NERVES MUSCLE & NERVE Olney, R. K., So, Y. T., Goodin, D. S., Aminoff, M. J. 1990; 13 (10): 957-963

    Abstract

    We compared magnetic stimulation using different coil designs (2 rounded coils and a butterfly-prototype coil) with electrical stimulation of the median and ulnar nerves in 5 normal subjects. Using magnetic stimulation we were able to record technically satisfactory maximal sensory and motor responses only with the butterfly coil. Submaximal electrical stimuli preferentially activated sensory rather than motor axons, but submaximal magnetic stimuli did not. The onset latency, amplitude, area and duration of responses elicited electrically or magnetically with the butterfly coil during routine sensory and motor nerve conduction studies were similar, and motor and sensory conduction velocities were comparable when studied over long segments of nerve. However, the motor conduction velocities with magnetic and electrical stimulation differed by as much as 18 m/sec in the across-elbow segment of ulnar nerve. Thus, recent developments in magnetic stimulator design have improved the focality of the stimulus, but the present butterfly coil design cannot replace electrical stimulation for the detection of focal changes in nerve conduction velocity at common entrapment sites, such as in the across-elbow segment of the ulnar nerve.

    View details for Web of Science ID A1990EA60700011

    View details for PubMedID 2233853

  • ACUTE FEMORAL NEUROPATHY AND ILIOPSOAS INFARCTION IN INTRAVENOUS DRUG-ABUSERS NEUROLOGY KAKU, D. A., So, Y. T. 1990; 40 (8): 1317-1318

    View details for Web of Science ID A1990DT48800040

    View details for PubMedID 2166251

  • MEDICAL SURVEILLANCE FOR NEUROLOGIC END-POINTS OCCUPATIONAL MEDICINE-STATE OF THE ART REVIEWS Cone, J. E., Bowler, R., So, Y. 1990; 5 (3): 547-562

    Abstract

    Except for screening for noise-induced hearing loss, medical surveillance for neurologic disease in the workplace has not been done on a routine basis in the past. In the future, however, as occupational medicine focuses increasingly on the detection of preclinical effects of exposure and strategies to prevent such exposures, medical surveillance for neurologic disease will become a necessity.

    View details for Web of Science ID A1990DX85800010

    View details for PubMedID 2218802

  • THERMOGRAPHY AND THE EVALUATION OF NEUROMUSCULAR DISORDERS SEMINARS IN NEUROLOGY Aminoff, M. J., Olney, R. K., So, Y. T. 1990; 10 (2): 150-155

    View details for Web of Science ID A1990DP75800007

    View details for PubMedID 2165271

  • THE ROLE OF THERMOGRAPHY IN THE EVALUATION OF LUMBOSACRAL RADICULOPATHY NEUROLOGY So, Y. T., Aminoff, M. J., Olney, R. K. 1989; 39 (9): 1154-1158

    Abstract

    We studied 27 normal subjects and 30 patients with low back pain to evaluate the diagnostic accuracy of thermography in the diagnosis of lumbosacral radiculopathy. Thermographic abnormality was defined as the presence of either interside temperature difference exceeding 3 standard deviations from the normal mean, or an abnormal heat pattern overlying the lumbosacral spine. In patients with clinically unequivocal radiculopathy, thermography and electrophysiologic study were similar in diagnostic sensitivity, and the 2 methods agreed on the presence or absence of abnormality in 71% of cases. However, the thermographic findings had limited localizing value. Relative limb warming was often seen in patients with acute denervation on EMG, and limb cooling in those with more chronic lesions, but the side of the root lesion could not be identified confidently by thermography alone. Moreover, thermographic abnormalities appeared not to follow a dermatomal distribution and failed to identify the clinical or electrophysiologic level of radiculopathy in most cases. Thus, the thermographic findings are nonspecific, of little diagnostic value, and of uncertain prognostic relevance.

    View details for Web of Science ID A1989AP30700003

    View details for PubMedID 2549451

  • NEW-ONSET SEIZURES ASSOCIATED WITH HUMAN IMMUNODEFICIENCY VIRUS-INFECTION - CAUSATION AND CLINICAL-FEATURES IN 100 CASES AMERICAN JOURNAL OF MEDICINE Holtzman, D. M., KAKU, D. A., So, Y. T. 1989; 87 (2): 173-177

    Abstract

    We attempt to define the significance and most common causes of new-onset seizures in patients with human immunodeficiency virus (HIV) infection. In addition, we review the seizure type, neurologic examination, and other clinical features to better address diagnostic and management issues in these patients.We reviewed 100 cases of new-onset seizures in HIV-infected patients who underwent complete evaluations at the University of California, San Francisco, hospitals.Seizures were the presenting symptom of HIV-related illness in 18 patients, six of whom developed no other HIV-related illness until at least four months after the first seizure. Common causes in the 100 patients included mass lesions, HIV encephalopathy, and meningitis. No cause for the seizures was found in 23 patients despite a complete evaluation. An underlying cause was found in all patients with focal neurologic deficits but in only two of 24 who had normal results on an interictal neurologic examination. Focal ictal features were not predictive of cause. A cause was found in all 12 patients with status epilepticus or medically refractory seizures. A total of 12 of the 87 (14%) patients who received phenytoin developed a hypersensitivity reaction. Despite the brevity of follow-up in some patients, many patients, including those with no definable cause, had multiple seizures prior to the administration of anticonvulsants.The direct effects of HIV on the brain may be the single most common cause of seizures in this population. We favor treatment of a single seizure in patients with HIV infection.

    View details for Web of Science ID A1989AH98600009

    View details for PubMedID 2757058

  • EVALUATION OF THERMOGRAPHY IN THE DIAGNOSIS OF SELECTED ENTRAPMENT NEUROPATHIES NEUROLOGY So, Y. T., Olney, R. K., Aminoff, M. J. 1989; 39 (1): 1-5

    Abstract

    We studied 20 normal subjects, 22 patients with carpal tunnel syndrome, and 15 with ulnar neuropathy at the elbow to compare the diagnostic accuracy of infrared thermography with that of conventional electrodiagnostic studies. We found abnormal thermograms in 55% of patients with carpal tunnel syndrome and 47% with ulnar neuropathy, using 2.5 SD from the normal mean as criteria for abnormality. The abnormalities consisted of either an increase in interside temperature difference in the fingers and hands or an alteration of the normal thenar-hypothenar temperature gradient in the fingers. The sensitivity of thermography was considerably lower than that of conventional electrodiagnostic methods. Moreover, the thermographic abnormalities were nonspecific, and could be misleading as they did not reliably identify the side of lesion or distinguish between median or ulnar nerve involvement. Thus, thermography is not helpful in the diagnosis of these two common entrapment neuropathies.

    View details for Web of Science ID A1989R746300001

    View details for PubMedID 2909896

  • PERIPHERAL NEUROPATHY ASSOCIATED WITH ACQUIRED IMMUNODEFICIENCY SYNDROME - PREVALENCE AND CLINICAL-FEATURES FROM A POPULATION-BASED SURVEY ARCHIVES OF NEUROLOGY So, Y. T., Holtzman, D. M., Abrams, D. I., Olney, R. K. 1988; 45 (9): 945-948

    Abstract

    We prospectively studied 40 hospitalized patients who had well-established diagnoses of acquired immunodeficiency syndrome. Patients with confounding risk factors for neuropathy were excluded; none of the study patients had known vitamin deficiency, alcoholism, or any metabolic, drug, or toxic factor. Clinical and electrophysiologic evidence of a distal symmetric polyneuropathy was found in 35% (13/37) of the patients. Symptoms and signs of neuropathy were usually mild, and painful dysesthesias were uncommon. Amplitude reduction of sural nerve action potentials distinguished all patients with from those without clinical neuropathy. Results of other electrophysiologic studies of sural, peroneal, and median nerves were typically normal. These results provide evidence of distal axonal degeneration. Neuropathy occurred only in patients with systemic illness longer than five months' duration. When compared with patients without neuropathy, these patients had more severe weight loss and a higher incidence of clinical dementia. Follow-up evaluation showed no evidence of clinical progression over a six-month period. The pathogenesis of this common distal axonal polyneuropathy is unknown and warrants further investigation.

    View details for Web of Science ID A1988P940200004

    View details for PubMedID 2843154

  • SUBACUTE STRUCTURAL MYOPATHY ASSOCIATED WITH HUMAN IMMUNODEFICIENCY VIRUS-INFECTION ARCHIVES OF NEUROLOGY Gonzales, M. F., Olney, R. K., So, Y. T., Greco, C. M., MCQUINN, B. A., MILLER, R. G., DeArmond, S. J. 1988; 45 (5): 585-587

    Abstract

    An unusual myopathy characterized by selective loss of thick filaments and widespread formation of rod bodies is described in two men, both seropositive for human immunodeficiency virus. We were unable to find any previous reports documenting this combination of morphological abnormalities, which we believe may be related to human immunodeficiency virus infection. Both patients responded to treatment: one, to steroid therapy; the other, to plasmapheresis.

    View details for Web of Science ID A1988N168200024

    View details for PubMedID 3358713

  • PRIMARY CENTRAL NERVOUS-SYSTEM LYMPHOMAS IN PATIENTS WITH AIDS ANNALS OF NEUROLOGY Rosenblum, M. L., Levy, R. M., Bredesen, D. E., So, Y. T., Wara, W., Ziegler, J. L. 1988; 23: S13-S16

    Abstract

    Primary central nervous system non-Hodgkin's lymphomas are observed in approximately 1.9% of all patients with acquired immunodeficiency syndrome (AIDS). The yearly incidence of AIDS-associated tumors has surpassed the yearly incidence from all other causes and could become as frequent as low-grade astrocytomas by 1991. Patients' signs, symptoms, and radiographic studies are not specific for this lesion; brain biopsy usually is necessary to make a definitive diagnosis. Most tumors are high-grade lymphomas and are pathologically similar to the primary central nervous system lymphomas observed before the AIDS epidemic. AIDS-associated tumors respond readily to radiation therapy. However, patient survival remains limited owing to other manifestations of the syndrome.

    View details for Web of Science ID A1988L991000006

    View details for PubMedID 2894803

  • MILIARY METASTASIS TO THE BRAIN - CLINICAL AND RADIOLOGIC FEATURES NEUROLOGY Floeter, M. K., So, Y. T., Ross, D. A., Greenberg, D. 1987; 37 (11): 1817-1818

    View details for Web of Science ID A1987K749200027

    View details for PubMedID 3670620

  • PRIMARY CENTRAL-NERVOUS-SYSTEM LYMPHOMA IN ACQUIRED-IMMUNE-DEFICIENCY-SYNDROME - A CLINICAL AND PATHOLOGICAL-STUDY ANNALS OF NEUROLOGY So, Y. T., Beckstead, J. H., Davis, R. L. 1986; 20 (5): 566-572

    Abstract

    Twenty cases of primary lymphoma of the central nervous system associated with acquired immune deficiency syndrome were seen over a period of four years and were studied clinically and pathologically. Biopsy established the diagnosis in 11 cases, and autopsy confirmed it in 9. Multicentricity was demonstrated in all cases for which there was adequate autopsy material. Both large-cell immunoblastic and small noncleaved lymphomas were seen, and marker studies in 5 patients established that the lymphomas were of B-cell origin. Neurological symptoms and signs, cerebrospinal fluid characteristics, and radiographic appearance were reviewed. The clinical and radiographic picture is nonspecific and histological confirmation is essential for diagnosis. Although the tumor appears to be radiosensitive, prognosis is extremely poor, with an average survival of less than two months.

    View details for Web of Science ID A1986E726200002

    View details for PubMedID 3789672

  • EOSINOPHILIC VASCULITIS LEADING TO AMAUROSIS FUGAX IN A PATIENT WITH ACQUIRED-IMMUNODEFICIENCY-SYNDROME ARCHIVES OF INTERNAL MEDICINE SCHWARTZ, N. D., So, Y. T., Hollander, H., Allen, S., Fye, K. H. 1986; 146 (10): 2059-2060

    Abstract

    A 49-year-old bisexual man with generalized lymphadenopathy and antihuman T lymphocyte virus, type III, (HTLV-III) antibodies presented with recurrent, unilateral amaurosis fugax. A temporal artery biopsy specimen showed eosinophilic vasculitis. The patient then developed acquired immunodeficiency syndrome with Kaposi's sarcoma. We describe this patient because of the unusual association of large vessel vasculitis and acquired immunodeficiency syndrome.

    View details for Web of Science ID A1986E259300030

    View details for PubMedID 3767551

  • SPATIAL TUNING OF CELLS IN AND AROUND LATERAL GENICULATE-NUCLEUS OF THE CAT - X AND Y RELAY CELLS AND PERIGENICULATE INTERNEURONS JOURNAL OF NEUROPHYSIOLOGY So, Y. T., Shapley, R. 1981; 45 (1): 107-120

    View details for Web of Science ID A1981LA21900008

    View details for PubMedID 6259298

  • IS THERE AN EFFECT OF MONOCULAR DEPRIVATION ON THE PROPORTIONS OF X-CELLS AND Y-CELLS IN THE CAT LATERAL GENICULATE-NUCLEUS EXPERIMENTAL BRAIN RESEARCH Shapley, R., So, Y. T. 1980; 39 (1): 41-48

    Abstract

    The proportions and receptive properties of X and Y cells in the A and A1 layers of the lateral geniculate nucleus (LGN) were studied in monocularly deprived cats. Contrary to previous reports, we found that there was no change in the relative number of Y cells in the geniculate layers driven by the deprived eye. There was also no marked change in the spatial resolution of X or Y cells driven from the deprived eye as compared to the cells driven from the normally experienced eye. In these same cats, the visual evoked potential from stimulation of the deprived eye with grating patterns was markedly reduced in amplitude. Furthermore, the cell bodies of the cells in the LGN driven by the deprived eye had shrunk. Therefore, these usual consequences of monocular deprivation are not necessarily associated with a loss of geniculate Y cells.

    View details for Web of Science ID A1980JQ53200006

    View details for PubMedID 7379885

  • SPATIAL PROPERTIES OF X-CELLS AND Y-CELLS IN THE LATERAL GENICULATE-NUCLEUS OF THE CAT AND CONDUCTION VELOCITIES OF THEIR INPUTS EXPERIMENTAL BRAIN RESEARCH So, Y. T., Shapley, R. 1979; 36 (3): 533-550

    Abstract

    Visual neurons in the lateral geniculate nucleus (LGN) of the cat may be separated into distinct X and Y classes based on a test of the linearity of spatial summation. Y cells produce nonlinear responses especially when the visual stimulus is a fine spatial grating. X cells exhibit mainly linear summation properties. X cells respond mainly at the fundamental modulation frequency of a contrast reversal grating while Y cells respond at the fundamental and at the second harmonic of the modulation frequency. The spatial resolution of X cells' fundamental responses and Y cells' second harmonic responses is about the same, and both are two to eight times higher than the spatial resolution of the Y cells' fundamental response. The conduction velocity of the Y optic tract afferents is greater than that of the velocity of the X afferents. However, the LGN latencies of the responses of the two classes of cells to optic chiasm stimulation overlap considerably.

    View details for Web of Science ID A1979HG22000010

    View details for PubMedID 477781

  • EFFECTS OF DARK-ADAPTATION ON SPATIAL AND TEMPORAL PROPERTIES OF RECEPTIVE-FIELDS IN CAT LATERAL GENICULATE-NUCLEUS JOURNAL OF PHYSIOLOGY-LONDON Kaplan, E., Marcus, S., So, Y. T. 1979; 294 (SEP): 561-580

    Abstract

    1. We studied the effect of dark adaptation on the spatial organization of receptive fields of single cells in the lateral geniculate nucleus l.g.n. of the cat. 2. Contrary to previous reports, we found that in many l.g.n. cells the ability of the receptive field surround to suppress the response of the centre was diminished following dark adaptation. 3. The degree of reduction of the surround antagonistic strength varied from cell to cell, and was independent of the various classifications of visual neurones (X/Y, ON/OFF, layer, A/layer, A1 and central/peripheral). 4. Most cells also showed an increase in the apparent size of the excitatory centre upon dark adaptation. On the average, the width of the most effective bar stimulus located at the centre of the receptive field increased more than twofold. 5. We also studied the effect of dark adaptation on the temporal properties of l.g.n. receptive fields. In many cells dark adaptation changed the temporal modulation transfer function: it flattened the amplitude function, and changed the phase relationship between the centre response and the surround response. 6. Retinal ganglion cells showed qualitatively similar behaviour to that of l.g.n. neurones. 7. Our data do not support the notion that retinal ganglion cell centres converge on l.g.n. cells to form their surround mechanism.

    View details for Web of Science ID A1979HN01100037

    View details for PubMedID 512958

Conference Proceedings


  • THE RELATIONSHIP BETWEEN ELECTROGRAPHIC SEIZURE ACTIVITY AND NEURONAL INJURY Lowenstein, D. H., Shimosaka, S., So, Y. T., Simon, R. P. ELSEVIER SCIENCE BV. 1991: 49-54

    View details for Web of Science ID A1991GT66900008

    View details for PubMedID 1790772

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