Bio

Clinical Focus


  • Essential Tremor
  • Palsy, Progressive Supranuclear
  • Dystonia Disorders
  • Multiple System Atrophy
  • Parkinson Disease
  • Ataxia
  • Parkinsonian Disorders
  • Blepharospasm
  • Huntington Disease
  • Tics
  • Neurology

Academic Appointments


Honors & Awards


  • Lysia Forno Award for Teaching Excellence, Stanford University (2009-2010)

Professional Education


  • Medical Education:Vanderbilt University School of Medicine (2002) TN
  • Internship:Univ of California San Francisco (2003) CA
  • Residency:Univ of California San Francisco (2006) CA
  • Fellowship:Columbia University Medical Center (2008) NY
  • Board Certification: Neurology, American Board of Psychiatry and Neurology (2007)
  • Post-Doc, Feinstein Institute, Functional Neuroimaging (2009)
  • BSE, University of Pennsylvania, Bioengineering
  • MS, Vanderbilt University, Bioengineering (1998)

Research & Scholarship

Current Research and Scholarly Interests


Dr. Poston’s research interests include the development, validation and application of functional and structural neuroimaging as biomarkers for the diagnosis and treatment of movement disorders. Specifically, her research focuses on using FDG PET and fMRI to understand abnormal brain networks that lead to both motor and cognitive dysfunction in patients with parkinsonism. She is also interested in the development of novel imaging analysis techniques for establishing diagnosis and monitoring disease progression in early parkinsonian disorders, such as Parkinson’s disease, multiple system atrophy, progressive supranuclear palsy, and corticobasal degeneration. Such techniques can be used in the development and testing of novel therapeutic interventions, such as gene transfer therapy in Parkinson’s disease.

Clinical Trials


  • Safety and Efficacy of CERE-120 in Subjects With Parkinson's Disease Not Recruiting

    The purpose of this study is to evaluate the safety and potential benefits of CERE-120 in the treatment of Parkinson's disease. CERE-120 is an experimental drug that consists of an adeno-associated virus (AAV) that was engineered to carry the human gene for neurturin, a neurotrophic (growth) factor. Similar to other growth factors (such as GDNF), neurturin is capable of restoring function and protecting brain cells from further damage. The virus used in CERE-120 is not known to cause disease in people. CERE-120 is delivered directly to the brain cells most affected in Parkinson's disease - the dopamine producing neurons. CERE-120 is injected during brain surgery. Once in place, CERE-120 continuously produces neurturin.

    Stanford is currently not accepting patients for this trial. For more information, please contact Sandra Dunn, (650) 724 - 8278.

    View full details

Teaching

2013-14 Courses


Graduate and Fellowship Programs


Publications

Journal Articles


  • Functional brain networks and abnormal connectivity in the movement disorders NEUROIMAGE Poston, K. L., Eidelberg, D. 2012; 62 (4): 2261-2270

    Abstract

    Clinical manifestations of movement disorders, such as Parkinson's disease (PD) and dystonia, arise from neurophysiological changes within the cortico-striato-pallidothalamocortical (CSPTC) and cerebello-thalamo-cortical (CbTC) circuits. Neuroimaging techniques that probe connectivity within these circuits can be used to understand how these disorders develop as well as identify potential targets for medical and surgical therapies. Indeed, network analysis of (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET) has identified abnormal metabolic networks associated with the cardinal motor symptoms of PD, such as akinesia and tremor, as well as PD-related cognitive dysfunction. More recent task-based and resting state functional magnetic resonance imaging studies have reproduced several of the altered connectivity patterns identified in these abnormal PD-related networks. A similar network analysis approach in dystonia revealed abnormal disease related metabolic patterns in both manifesting and non-manifesting carriers of dystonia mutations. Other multimodal imaging approaches using magnetic resonance diffusion tensor imaging in patients with primary genetic dystonia suggest abnormal connectivity within the CbTC circuits mediate the clinical manifestations of this inherited neurodevelopmental disorder. Ongoing developments in functional imaging and future studies in early patients are likely to enhance our understanding of these movement disorders and guide novel targets for future therapies.

    View details for DOI 10.1016/j.neuroimage.2011.12.021

    View details for Web of Science ID 000308265200010

    View details for PubMedID 22206967

  • Network correlates of disease severity in multiple system atrophy NEUROLOGY Poston, K. L., Tang, C. C., Eckert, T., Dhawan, V., Frucht, S., Vonsattel, J., Fahn, S., Eidelberg, D. 2012; 78 (16): 1237-1244

    Abstract

    Multiple system atrophy (MSA), the most common of the atypical parkinsonian disorders, is characterized by the presence of an abnormal spatial covariance pattern in resting state metabolic brain images from patients with this disease. Nonetheless, the potential utility of this pattern as a MSA biomarker is contingent upon its specificity for this disorder and its relationship to clinical disability in individual patients.We used [(18)F]fluorodeoxyglucose PET to study 33 patients with MSA, 20 age- and severity-matched patients with idiopathic Parkinson disease (PD), and 15 healthy volunteers. For each subject, we computed the expression of the previously characterized metabolic covariance patterns for MSA and PD (termed MSARP and PDRP, respectively) on a prospective single-case basis. The resulting network values for the individual patients were correlated with clinical motor ratings and disease duration.In the MSA group, disease-related pattern (MSARP) values were elevated relative to the control and PD groups (p < 0.001 for both comparisons). In this group, MSARP values correlated with clinical ratings of motor disability (r = 0.57, p = 0.0008) and with disease duration (r = -0.376, p = 0.03). By contrast, MSARP expression in the PD group did not differ from control values (p = 1.0). In this group, motor ratings correlated with PDRP (r = 0.60, p = 0.006) but not with MSARP values (p = 0.88).MSA is associated with elevated expression of a specific disease-related metabolic pattern. Moreover, differences in the expression of this pattern in patients with MSA correlate with clinical disability. The findings suggest that the MSARP may be a useful biomarker in trials of new therapies for this disorder.

    View details for DOI 10.1212/WNL.0b013e318250d7fd

    View details for Web of Science ID 000302933200010

    View details for PubMedID 22491861

  • AAV2-GAD gene therapy for advanced Parkinson's disease: a double-blind, sham-surgery controlled, randomised trial LANCET NEUROLOGY LeWitt, P. A., Rezai, A. R., Leehey, M. A., Ojemann, S. G., Flaherty, A. W., Eskandar, E. N., Kostyk, S. K., Thomas, K., Sarkar, A., Siddiqui, M. S., Tatter, S. B., Schwalb, J. M., Poston, K. L., Henderson, J. M., Kurlan, R. M., Richard, I. H., Van Meter, L., Sapan, C. V., During, M. J., Kaplitt, M. G., Feigin, A. 2011; 10 (4): 309-319

    Abstract

    Gene transfer of glutamic acid decarboxylase (GAD) and other methods that modulate production of GABA in the subthalamic nucleus improve basal ganglia function in parkinsonism in animal models. We aimed to assess the effect of bilateral delivery of AAV2-GAD in the subthalamic nucleus compared with sham surgery in patients with advanced Parkinson's disease.Patients aged 30-75 years who had progressive levodopa-responsive Parkinson's disease and an overnight off-medication unified Parkinson's disease rating scale (UPDRS) motor score of 25 or more were enrolled into this double-blind, phase 2, randomised controlled trial, which took place at seven centres in the USA between Nov 17, 2008, and May 11, 2010. Infusion failure or catheter tip location beyond a predefined target zone led to exclusion of patients before unmasking for the efficacy analysis. The primary outcome measure was the 6-month change from baseline in double-blind assessment of off-medication UPDRS motor scores. This trial is registered with ClinicalTrials.gov, NCT00643890.Of 66 patients assessed for eligibility, 23 were randomly assigned to sham surgery and 22 to AAV2-GAD infusions; of those, 21 and 16, respectively, were analysed. At the 6-month endpoint, UPDRS score for the AAV2-GAD group decreased by 8·1 points (SD 1·7, 23·1%; p<0·0001) and by 4·7 points in the sham group (1·5, 12·7%; p=0·003). The AAV2-GAD group showed a significantly greater improvement from baseline in UPDRS scores compared with the sham group over the 6-month course of the study (RMANOVA, p=0·04). One serious adverse event occurred within 6 months of surgery; this case of bowel obstruction occurred in the AAV2-GAD group, was not attributed to treatment or the surgical procedure, and fully resolved. Other adverse events were mild or moderate, likely related to surgery and resolved; the most common were headache (seven patients in the AAV2-GAD group vs two in the sham group) and nausea (six vs two).The efficacy and safety of bilateral infusion of AAV2-GAD in the subthalamic nucleus supports its further development for Parkinson's disease and shows the promise for gene therapy for neurological disorders.Neurologix.

    View details for DOI 10.1016/S1474-4422(11)70039-4

    View details for Web of Science ID 000289185000014

    View details for PubMedID 21419704

  • Differential diagnosis of parkinsonism: a metabolic imaging study using pattern analysis LANCET NEUROLOGY Tang, C. C., Poston, K. L., Eckert, T., Feigin, A., Frucht, S., Gudesblatt, M., Dhawan, V., Lesser, M., Vonsattel, J., Fahn, S., Eidelberg, D. 2010; 9 (2): 149-158

    Abstract

    Idiopathic Parkinson's disease can present with symptoms similar to those of multiple system atrophy or progressive supranuclear palsy. We aimed to assess whether metabolic brain imaging combined with spatial covariance analysis could accurately discriminate patients with parkinsonism who had different underlying disorders.Between January, 1998, and December, 2006, patients from the New York area who had parkinsonian features but uncertain clinical diagnosis had fluorine-18-labelled-fluorodeoxyglucose-PET at The Feinstein Institute for Medical Research. We developed an automated image-based classification procedure to differentiate individual patients with idiopathic Parkinson's disease, multiple system atrophy, and progressive supranuclear palsy. For each patient, the likelihood of having each of the three diseases was calculated by use of multiple disease-related patterns with logistic regression and leave-one-out cross-validation. Each patient was classified according to criteria defined by receiver-operating-characteristic analysis. After imaging, patients were assessed by blinded movement disorders specialists for a mean of 2.6 years before a final clinical diagnosis was made. The accuracy of the initial image-based classification was assessed by comparison with the final clinical diagnosis.167 patients were assessed. Image-based classification for idiopathic Parkinson's disease had 84% sensitivity, 97% specificity, 98% positive predictive value (PPV), and 82% negative predictive value (NPV). Imaging classifications were also accurate for multiple system atrophy (85% sensitivity, 96% specificity, 97% PPV, and 83% NPV) and progressive supranuclear palsy (88% sensitivity, 94% specificity, 91% PPV, and 92% NPV).Automated image-based classification has high specificity in distinguishing between parkinsonian disorders and could help in selecting treatment for early-stage patients and identifying participants for clinical trials.National Institutes of Health and General Clinical Research Center at The Feinstein Institute for Medical Research.

    View details for DOI 10.1016/S1474-4422(10)70002-8

    View details for Web of Science ID 000273922000012

    View details for PubMedID 20061183

  • Abnormalities in Metabolic Network Activity Precede the Onset of Motor Symptoms in Parkinson's Disease JOURNAL OF NEUROSCIENCE Tang, C. C., Poston, K. L., Dhawan, V., Eidelberg, D. 2010; 30 (3): 1049-1056

    Abstract

    Imaging studies show that Parkinson's disease (PD) alters the activity of motor- and cognition-related metabolic brain networks. However, it is not known whether the network changes appear at or before symptom onset. In this study, we examined 15 hemiparkinsonian patients who underwent serial metabolic imaging with [(18)F]-fluorodeoxyglucose (FDG) PET at baseline and again 2.1 +/- 0.6 (mean +/- SD) and 3.9 +/- 0.7 years later. We assessed longitudinal changes in network activity in each cerebral hemisphere, focusing specifically on the "presymptomatic" hemisphere--ipsilateral to the initially involved body side. At the network level, the activity of the PD motor-related pattern (PDRP) increased symmetrically in both hemispheres over time (p < 0.001), with significant bilateral elevations at each of the three time points. Hemispheric expression of the PD cognition-related pattern likewise increased symmetrically (p < 0.001), although significant elevations were not evident on either side until 4 years. At the regional level, putamen metabolism contralateral to the initially affected body side was elevated at all three time points, without longitudinal change. In contrast, in the initially presymptomatic hemisphere, putamen metabolic activity increased steadily over time, reaching abnormal levels only at 4 years. Metabolic activity in the contralateral precuneus fell to subnormal levels by the final time point. These findings suggest that abnormal PDRP activity antecedes the appearance of motor signs by approximately 2 years. The timing and laterality of symptom onset relates to focal asymmetric metabolic changes at the putamenal node of this network.

    View details for DOI 10.1523/JNEUROSCI.4188-09.2010

    View details for Web of Science ID 000273779200026

    View details for PubMedID 20089913

  • Fragile X-Associated Tremor/Ataxia Syndrome (FXTAS) with Myoclonus MOVEMENT DISORDERS Poston, K. L., McGovern, R. A., Goldman, J. S., Caccappolo, E., Mazzoni, P. 2010; 25 (4): 514-516

    View details for DOI 10.1002/mds.22929

    View details for Web of Science ID 000276337400027

    View details for PubMedID 20063436

  • FDG PET in the Evaluation of Parkinson's Disease. PET clinics Poston, K. L., Eidelberg, D. 2010; 5 (1): 55-64

    Abstract

    Network analysis of (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET) is an innovative approach for the study of in movement disorders, such as Parkinson's disease (PD). Spatial covariance analysis of imaging data acquired from PD patients has revealed characteristic regional patterns associated with the motor and cognitive features of disease. Quantification of pattern expression in individual patients can be used for diagnosis, assessment of disease severity, and evaluation of novel medical and surgical therapies. Identification of disease-specific patterns in other parkinsonian syndromes, such as multiple system atrophy and progressive supranuclear palsy, has improved diagnostic accuracy in patients with difficult to diagnose parkinsonism. Further developments of these techniques are likely to enhance the role of functional imaging in investigating underlying abnormalities and potential new therapies in these neurodegenerative diseases.

    View details for PubMedID 20689674

  • Action tremor of the legs in essential tremor: Prevalence, clinical correlates, and comparison with age-matched controls PARKINSONISM & RELATED DISORDERS Poston, K. L., Rios, E., Louis, E. D. 2009; 15 (8): 602-605

    Abstract

    The hallmark feature of essential tremor (ET) is action tremor of the arms. Leg tremor may also occur yet it has not been the central focus of previous studies. Its prevalence has only rarely been reported, its clinical correlates have yet to be explored. Our aims were to report the prevalence and analyze the clinical correlates of leg action tremor in patients with ET and, given the propensity for normal elderly individuals to manifest mild limb tremors, compare the prevalence with that in age-matched controls. Kinetic leg tremor rated > or =1 occurred in 28/63 (44.4%) ET cases and in only 9/63 (14.3%) controls (p<0.001); moderate leg tremor occurred in 14.3% of cases. Leg tremor severity modestly correlated with disease duration (r=0.31, p=0.02). However, the severity and laterality of leg tremor did not correlate with those of arm tremor. The pathophysiological implications of this finding deserve further exploration.

    View details for DOI 10.1016/j.parkreldis.2008.11.006

    View details for Web of Science ID 000270122500011

    View details for PubMedID 19103506

  • Network biomarkers for the diagnosis and treatment of movement disorders NEUROBIOLOGY OF DISEASE Poston, K. L., Eidelberg, D. 2009; 35 (2): 141-147

    Abstract

    Functional brain networks provide a set of useful biomarkers for the assessment of movement disorders such as Parkinson's disease (PD). Spatial covariance analysis of imaging data from PD patients has led to the identification of abnormal metabolic patterns associated with the motor and cognitive features of this disease. Measurements of pattern expression have been used for diagnosis, assessment of rates of disease progression, and objective evaluation of the efficacy of therapeutic interventions. For instance, the recent identification of new disease-specific patterns for Multiple System Atrophy (MSA) and Progressive Supranuclear Palsy (PSP) has improved diagnostic accuracy in patients with parkinsonian syndromes. Further, disease-related networks have been found to be modulated by novel treatment strategies such as gene therapy. Finally, the application of network analysis to the study of inherited movement disorders such as Huntington's disease can aid in the assessment of disease-modifying therapies in pre-symptomatic gene mutation carriers.

    View details for DOI 10.1016/j.nbd.2008.09.026

    View details for Web of Science ID 000268078300004

    View details for PubMedID 19013242

  • Movement disorder emergencies JOURNAL OF NEUROLOGY Poston, K. L., Frucht, S. J. 2008; 255: 2-13

    Abstract

    Movement disorder emergencies include any movement disorder which evolves over hours to days, in which failure to appropriately diagnose and manage can result in patient morbidity or mortality. It is crucial that doctors recognize these emergencies with accuracy and speed by obtaining the proper history and by being familiar with the phenomenology of frequently encountered movements. These disorders will be discussed based on the most common associated involuntary movement, either parkinsonism, dystonia, chorea, tics or myoclonus, and, when available, review the workup and treatment options based on the current literature.

    View details for DOI 10.1007/s00415-008-4002-9

    View details for Web of Science ID 000259034000002

    View details for PubMedID 18821080

  • Zydis selegilline in the management of Parkinson's disease EXPERT OPINION ON PHARMACOTHERAPY Poston, K. L., Waters, C. 2007; 8 (15): 2615-2624

    Abstract

    Selegiline, a selective monoamine oxidase-B inhibitor, has been used for decades in the treatment of Parkinson's disease. The recent development of an orally disintegrating dosage form using Zydis technology allows pregastric drug absorption and, thus, greatly improving the pharmacodynamic and pharmacokinetic drug profiles. This new formulation provides higher drug bioavailability and a substantially reduced concentration of active metabolites. As an adjunct to levodopa, Zydis selegiline is shown to be a safe and effective therapy in patients with motor fluctuations and wearing off. This review outlines the advantages of a Zydis formulation in Parkinson's disease and the evidence supporting the use of Zydis selegiline for motor fluctuations.

    View details for DOI 10.1517/14656566.8.15.2615

    View details for Web of Science ID 000250426000014

    View details for PubMedID 17931095

Stanford Medicine Resources: