Gregory S Day, MD MSc FRCPC

Instructor in Neurology

Phone: 314-286-1967

Additional Titles

  • Clinical Director, The Anti-NMDA Receptor Encephalitis Foundation

Related Links


  • 2006, Masters of Science (Physiology/Neuroscience): Queen’s University, Kingston, Ontario, Canada
  • 2009, Medical Doctorate: Queen’s University, Kingston, Ontario, Canada
  • 2014, Postgraduate Medical Education (Residency), Adult Neurology: University of Toronto, Toronto, Ontario, Canada
  • 2015, Postdoctoral Fellowship (Memory and Aging): Washington University in St. Louis, St. Louis, MO

Board Certifications

  • Fellow of the Royal College of Physicians and Surgeons of Canada (board certification in Neurology)


  • John Wherrett Award for Outstanding Neurology Resident Research, University of Toronto (2013)
  • Future Leader in Dementia Award, Pfizer Canada (2013)
  • André Barbeau Memorial Prize for Basic Science Research, Canadian Neurological Society (2014)
  • J.T. Marotta Teaching Award, University of Toronto, Department of Medicine (2014)
  • Eugene M Johnson, Jr. Weston Brain Institute Postdoctoral Fellowship, Weston Brain Institute (2015)
  • Distinguished Reviewer of the Year, Canadian Journal of Neurological Sciences (2015)
  • American Brain Foundation, Clinical Research Training Fellowship (2016)

Clinical Interests

I maintain special clinical interest in the diagnosis and management of patients with rapidly progressive dementia (including Creutzfeldt-Jakob disease), and autoimmune-mediated encephalitis (including patients with NMDA-receptor encephalitis and similar diseases).

Research Interests

My research strives to integrate clinical (e.g., symptoms and signs) and paraclinical measures (e.g., structural/functional/PET neuroimaging, cerebrospinal fluid biomarkers) to inform the pathophysiology of neurodegenerative and autoimmune causes of dementia, while improving diagnostic accuracy, access to disease-modifying therapies, and patient outcomes.


Publications (selected):

  1. Day GS, Lim TS, Hassenstab J, Goate AM, Grant EA, Roe CM, Cairns NJ, Morris JC (2017) Differentiating cognitive impairment due to corticobasal degeneration and Alzheimer disease. Neurology. In press.
  2. Day GS, Musiek ES, Roe CM, Norton J, Goate AM, Cruchaga C, Cairns NJ, Morris JC (2016) Phenotypic similarities between late-onset autosomal dominant and sporadic Alzheimer disease: A single-family case-control study. JAMA Neurology: 73(9): 1125-32
  3. Britt DMI, Day GS (2016) Over-Prescribed Medications, Under-Appreciated Risks: A review of the cognitive effects of anticholinergic medicine. Missouri Medicine. 113(3):207-14
  4. Day GS, Tang-Wai DF, Shamy MCF (2016) A Case Study in the History of Neurology. Neurohospitalist: 6(4): 181-4
  5. Fischer CE, Golas A, Schweizer TA, Munoz DG, Ismail Z, Qian W, Tang-Wai DF, Rotstein D, Day GS (2016) Anti-NMDA receptor encephalitis: A Game Changer? Expert Review of Neurotherapeutics. 16(7):849-59
  6. Brier MR, Day GS, Snyder AZ, Tanenbaum AB, Ances BM (2016) N-methyl-D-aspartate receptor encephalitis mediates loss of intrinsic activity measured by functional MRI. Journal of Neurology. 263(6):1083-91.
  7. Day GS, Prüss H, Benseler S, Paton TA, Paterson A, Andrade DM (2015) GRIN1 polymorphisms do not effect susceptibility or phenotype in N-methyl-D-aspartate receptor encephalitis: clinical associations and implications. Neurology: Neuroimmunology & Neuroinflammation. 2(5):e153.
  8. Day GS, Carette S, Tang-Wai DF (2015) Primary angiitis of the central nervous system: Making the rare diagnosis in the familiar patient. Canadian Medical Association Journal. 187(10):750-4.
  9. Day GS, Ladak S, Curley K, Farb NAS, Masiowski P, Pringsheim T, Ritchie M, Cheung A, Jansen S, Methot L, Neville H, Bates D, Lowe D, Fernandes N, Ferland A, del Campo CM (2015) Thiamine prescribing practices within university-affiliated hospitals. Journal of Hospital Medicine. 10(4):246-53.
  10. Day GS, Laiq S, Tang-Wai DF, Munoz DG (2014) Abnormal neurons distinguish teratomas in anti-N-methyl-D-aspartate receptor encephalitis. JAMA Neurology. 71(6):717-24.
  11. Day GS, Tang-Wai DF (2014) When dementias progress quickly: a practical approach to diagnosis and management of rapidly progressive dementia. Neurodegenerative Disease Management. 4(1):41-56.
  12. Day GS, Farb NAS, Tang-Wai DF, Masellis M, Black SE, Freedman M, Pollock BG, Chow TW (2013) Salience network resting-state activity predicts progression in frontotemporal dementia. JAMA Neurology. 70(10):1249-53.
  13. Peery HE, Day GS, Doja A, Xia C, Fritzler M, Foster WG (2013) Anti-NMDA Receptor Encephalitis in Children. In O Dulac et al (Eds), Handbook of Clinical Neurology (Volume 112, 3rd series) Pediatric Neurology Part II. 112:1229-33. Amsterdam, The Netherlands: Elsevier
  14. Peery HE, Day GS, Dunn S, Fritzler MJ, Prüss H, De Souza C, Doja A, Mossman K, Resch L, Xia C, Sakic B, Belbeck L, Foster WG (2012) Anti-NMDA Receptor Encephalitis: The disorder, the diagnosis and the immunobiology. Autoimmunity Reviews. 11:863-72
  15. Day GS, High S, Cot B, Tang-Wai D (2011) Anti-NMDA-Receptor Encephalitis: Case Report and Literature Review of an Under-Recognized Condition. Journal of General Internal Medicine. 26(7):811-6

For a complete list of publications, see: