Bio

Bio


As a sleep specialist and clinical neurophysilogist, his research aims is to identify the physiological markers in sleep for cognitive impairment in a broad range of disorders, including neurodevelopment disorders, Alzheimer’s disease (AD), and sleep disorders. Using neurophysiological and neuroimaging approaches to investigating the impact of sleep, his research aims to: (1) more fully characterize sleep abnormality and physiological mechanisms underlying normal and pathological cognitive impairment; (2) assist with early identification of sleep disorders at greatest risk for cognitive decline; (3) develop interventions in sleep disorders aimed at reducing cognitive impairment.

Clinical Focus


  • Sleep Medicine

Professional Education


  • Fellowship:Stanford University (2014) CA
  • Board Certification: Epilepsy, American Board of Psychiatry and Neurology (2013)
  • Board Certification: Clinical Neurophysiology, American Board of Psychiatry and Neurology (2009)
  • Board Certification: Neurology, American Board of Psychiatry and Neurology (2007)
  • Board Certification: Sleep Medicine, American Board of Psychiatry and Neurology (2007)
  • Fellowship:Baylor College of Medicine (2006) TX
  • Residency:Baylor College of Medicine (2005) TX
  • Internship:St. Luke's-Roosevelt Hospital Center (2002) NY
  • Medical Education:Kyoto University, Faculty of Medicine (1997) Japan
  • Doctor, Kyoto University (2008)
  • Doctor of Medicine, Kyoto University (1997)

Stanford Advisors


Publications

All Publications


  • Longitudinal association of delta activity at sleep onset with cognitive and affective function in community-dwelling older adults. International journal of geriatric psychiatry Kawai, M., Beaudreau, S. A., Gould, C. E., Hantke, N. C., Cotto, I., Jordan, J. T., Hirst, R. B., O'Hara, R. 2016; 31 (10): 1124-1135

    Abstract

    This investigation sought to determine whether delta activity at sleep onset (DASO) in the sleep electroencephalography of older adults represents normal variation or is associated with clinical pathology. To this end, we examined its longitudinal associations with cognitive and affective function in older adults without dementia.Participants were 153 community-dwelling older adults without dementia. We evaluated polysomnography (PSG), cognitive performance, and affective function at four time points: baseline, 12, 24, and 36?months. All participants completed PSG and measures of global cognition, delayed verbal memory, information processing speed, attention, inhibition, verbal naming, visuospatial ability, and measures of anxiety and depression. DASO was defined as sequences of rhythmic anterior delta activity on PSG in the transition from awake to sleep during the baseline assessment (Figure ).At the baseline, 83 women and 70 men, mean age 71.3?±?0.6?years participated and 19.6% of participants exhibited DASO. Age, years of education, gender, and body mass index did not differ according to DASO status. Linear mixed modeling showed that the presence of DASO was actually associated with lower levels of anxiety and depression. Further, participants with DASO, versus those without DASO, exhibited a trend towards better cognitive performance over time, although none of these associations reached statistical significance.Whereas DASO was associated with better affective function, no significant association was found between DASO and cognitive change over time. These longitudinal findings support the view that the presence of DASO in healthy older adults represents normal variation rather than pathological aging. Copyright © 2016 John Wiley & Sons, Ltd.

    View details for DOI 10.1002/gps.4554

    View details for PubMedID 27554208

  • Tonsillectomy for adult obstructive sleep apnea: A systematic review and meta-analysis. Laryngoscope Camacho, M., Li, D., Kawai, M., Zaghi, S., Teixeira, J., Senchak, A. J., Brietzke, S. E., Frasier, S., Certal, V. 2016; 126 (9): 2176-2186

    Abstract

    To determine if sleepiness and sleep study variables (e.g., Apnea-Hypopnea Index [AHI] and lowest oxygen saturation) improve following isolated tonsillectomy for adult obstructive sleep apnea (OSA).Systematic review and meta-analysis.Nine databases (PubMed/MEDLINE included) were searched through November 24, 2015.Seventeen studies (n = 216 patients, 34.4 ± 10.0 years and body mass index: 29.0 ± 6.1 kg/m(2) ) met criteria. Tonsils sizes were hypertrophied, large, enlarged, extremely enlarged, or grades 2 to 4. Apnea-Hypopnea Index decreased by 65.2% (from 40.5 ± 28.9/hour to 14.1 ± 17.1/hour) (n = 203). The AHI mean difference (MD) was -30.2 per hour (95% confidence interval [CI] -39.3, -21.1) (P value < 0.00001). The AHI SMD was -1.37 (-1.65, -1.09) (large effect). Lowest oxygen saturation improved from 77.7 ± 11.9% to 85.5 ± 8.2% (n = 186). Lowest oxygen saturation MD was 8.5% (95% CI 5.2, 11.8) (P value < 0.00001). The Epworth Sleepiness Scale decreased from 11.6 ± 3.7 to 6.1 ± 3.9 (P value < 0.00001) (n = 125). Individual patient outcomes (n = 54) demonstrated an 85.2% success rate (AHI < 20/hour and ? 50% reduction) and a 57.4% cure rate. Individual patient data meta-analysis showed preoperative AHI < 30 per hour to be a significant predictor of surgical success (P value < 0.001) and cure (P value = 0.043); among patients with preoperative AHI < 30 per hour, tonsillectomy success rate was 100% (25 of 25) and cure rate was 84% (21 of 25) with a mean postoperative AHI of 2.4 ± 2.1 per hour; this compares to tonsillectomy success rate of 72.4% (21 of 29), cure rate of 10 of 29 (34.4%), and mean postoperative AHI of 14.3 ± 13.9 per hour for patients with preoperative AHI ? 30 per hour.Isolated tonsillectomy can be successful as treatment for adult OSA, especially among patients with large tonsils and mild to moderate OSA (AHI < 30/hour). Laryngoscope, 2016 Laryngoscope, 126:2176-2186, 2016.

    View details for DOI 10.1002/lary.25931

    View details for PubMedID 27005314

  • Delta Activity at Sleep Onset and Cognitive Performance in Community-Dwelling Older Adults SLEEP Kawai, M., Beaudreau, S. A., Gould, C. E., Hantke, N. C., Jordan, J. T., O'Hara, R. 2016; 39 (4): 907-914

    View details for DOI 10.5665/sleep.5652

    View details for Web of Science ID 000373186900022

  • Five-Minute Awake Snoring Test for Determining CPAP Pressures (Five-Minute CPAP Test): A Pilot Study. Sleep disorders Camacho, M., Ruoff, C. M., Kawai, M., Modi, R., Arbee, J., Hekmat, A., Robertson, M., Zaghi, S., Certal, V., Capasso, R., Kushida, C. A. 2016; 2016: 7380874-?

    Abstract

    Objective. To develop a quick, simple, bedside test for determining continuous positive airway pressures (CPAP) for obstructive sleep apnea (OSA) patients. Study Design. Prospective case series at a tertiary medical center. Methods. The Five-Minute Awake Snoring Test for Determining CPAP (Five-Minute CPAP Test) was developed and tested. Patients wear a soft-gel nasal triangle mask while holding a tongue depressor with the wide section (1.75?cm) between the teeth. Fixed pressure nasal CPAP is applied while the patient simulates snoring at 4 centimeters of water pressure. The pressure is incrementally titrated up and then down to determine the lowest pressure at which the patient cannot snore (Quiet Pressure). Results. Overall, thirty-eight patients participated. All could simulate snoring. Correlation coefficients were statistically significant between Quiet Pressures and body mass index (r s = 0.60 [strong positive relationship], p = 0.0088), apnea-hypopnea index (r s = 0.49 [moderate positive relationship], p = 0.039), lowest oxygen saturation (r s = -0.47 [moderate negative relationship], p = 0.048), and oxygen desaturation index (r s = 0.62 [strong positive relationship], p = 0.0057). Conclusion. This pilot study introduces a new concept, which is the final product of over one year of exploration, development, and testing. Five-Minute CPAP Test is a quick, inexpensive, and safe bedside test based on supine awake simulated snoring with nasal CPAP.

    View details for DOI 10.1155/2016/7380874

    View details for PubMedID 26881088

  • Delta Activity at Sleep Onset and Cognitive Performance in Community-Dwelling Older Adults. Sleep Kawai, M., Beaudreau, S. A., Gould, C. E., Hantke, N. C., Jordan, J. T., O'Hara, R. 2016; 39 (4): 907-914

    Abstract

    Frontal intermittent rhythmic delta activity (FIRDA) has long been considered to be an abnormal variant in the electroencephalogram (EEG) among older adults. Prior work also indicates a predominance of slow wave EEG activity among patients with dementia. However, instability of state control occurring with aging generally and among many neurodegenerative diseases raises the possibility that FIRDA might represent the intrusion of sleep related elements of the EEG into the waking state. We examined delta activity at sleep onset (DASO) in community-dwelling, older adults without dementia, and examined whether this activity is related to poorer cognitive performance.153 community-dwelling, older adults without dementia underwent overnight polysomnography and measures of global cognition, delayed verbal memory, information processing speed, attention, inhibition, verbal naming, and visuospatial ability. Delta activity during sleep/wake transitions (scored either as Waking or N1) was analyzed visually.Participants were 83 women and 70 men, mean age 71.3 ± 0.6 y. DASO was present in 30 participants (19.6%). Age, years of education, sex, and body mass index did not differ between DASO (+) and (-) groups. Multiple regression analyses indicated faster reading of the Stroop color words in DASO (+) subjects (P = 0.007). None of the other cognitive domains differed between the two groups.DASO was relatively common in our sample of community-dwelling, older adults without dementia. DASO was not associated with poorer performance on any cognitive domain. Instead, individuals with DASO demonstrated better performance on a simple reading task. Although these findings suggest that an abnormal EEG activity may represent normal variation, our work underscores the importance of distinguishing DASO from FIRDA when examining sleep in older adults.A commentary on this article appears in this issue on page 725.

    View details for DOI 10.5665/sleep.5652

    View details for PubMedID 26943464

  • Narcolepsy in African Americans SLEEP Kawai, M., O'Hara, R., Einen, M., Lin, L., Mignot, E. 2015; 38 (11): 1673-1681

    View details for DOI 10.5665/sleep.5140

    View details for Web of Science ID 000363740100006

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