View updated information about our visitor policy  »
Book an appointment at our COVID-19 Assessment Centre (new location) »

Hospital  >  Departments  >  Medicine  >  Divisions  >  Neurology  >  Neurologists

Medicine Care Team


Dr. Andrew Lim, MD, FRCPC


Sunnybrook Health Sciences Centre
2075 Bayview Ave., Room M1 600
Toronto, ON
M4N 3M5

Phone: 416-480-6100, ext. 2461
Fax: 416-480-6092

Administrative Assistant: Richelle Bercasio
Phone: 416-480-6100 ext. 2461


  • B.Sc., 1999, microbiology and immunology, University of British Columbia, Canada
  • MD, 2003, University of Toronto, Canada
  • FRCPC, 2008, adult neurology, Royal College of Physicians and Surgeons of Canada
  • Diploma in electroencephalography, 2008, Canadian Society of Clinical Neurophysiologists
  • Clinical fellowship, 2009, sleep medicine, Harvard University, U.S.
  • MMSc, 2011, clinical investigation, Harvard University, U.S.

Appointments and Affiliations:

Research Foci:

  • Sleep and circadian biology
  • Noninvasive ambulatory monitoring of sleep and circadian rhythms
  • Genetic epidemiology of sleep and circadian traits
  • Impact of sleep and circadian function on cognitive decline, dementia and neurodegenerative diseases

Research Summary:

Dr. Lim’s research is focused on answering three broad questions:

  • What is the impact of sleep and circadian rhythm disruption on human brain health, from neurobiological mechanisms to health outcomes?;
  • What are the genetic mechanisms contributing to human sleep and circadian function, and how can we modify their impact on brain health?; and
  • What are the molecular substrates of circadian and seasonal rhythms of human brain biology in health and disease?

To answer these questions, and in collaboration with laboratories in Toronto and elsewhere, he uses a number of complementary techniques. These include the following:

  • ambulatory at-home measurement of sleep and circadian biology using wearable devices;
  • genome-wide association analyses and other population genetic approaches;
  • time-series analysis of genome-scale RNA sequencing, DNA methylation, and ChIP-seq (chromatin immunoprecipitation sequencing) data;
  • MR brain imaging;
  • computer-assisted psychometric testing;
  • human brain histopathology; and
  • linkage to administrative health databases.

He is applying these techniques in several large studies including:

  • The Ontario Sleep Health Study, which has prospectively obtained objective sleep and circadian measurements and blood samples from more than 2,000 Ontarians, of whom more than 300 have had brain MR imaging and psychometric testing. The team also has consent for linkage to administrative health databases at the Institute for Clinical Evaluative Sciences.
  • The Sunnybrook Brain Changes in Sleep Apnea study, in collaboration with Dr. Sandra Black and Dr. Brad Macintosh. The researchers will obtain detailed ambulatory measures of sleep physiology and cardiovascular physiology, detailed brain MR imaging, and psychometric testing on patients with severe sleep apnea before and after treatment with a continuous positive airway pressure device.
  • The Memory and Aging project, in collaboration with Dr. David Bennett and Dr. Aron Buchman. This study will use ambulatory measurements of sleep and rest patterns from more than 1,500 older adults. The researchers will also obtain sleep and cardiovascular measurements from more than1,000 study participants while linking these sleep and circadian data to cognitive outcomes, MR imaging, genotype, genome-scale transcriptome and epigenome data, and postmortem histopathology.

Work in the laboratory is funded by grants from the Canadian Institutes of Health Research, the National Institute on Aging, and the Ontario Ministry of Research, Innovation and Science.

The laboratory is looking to take on one or more graduate students at the master’s level through the Institute of Medical Science at U of T, as well as residents or medical students interested in undertaking sleep and circadian rhythm-related research projects, starting in the 2017–2018 academic year. In particular, Dr. Lim is looking for candidates with programming (especially R and MATLAB) and statistics experience, coupled with undergraduate-level knowledge of mathematics, genetics and neurobiology. If interested in applying, then please contact Dr. Lim at

Selected Publications:

See current publications list at PubMed.

  1. Lim AS, Klein HU, Yu L, Chibnik LB, Ali S, Xu J, Bennett DA, De Jager PL. Diurnal and seasonal molecular rhythms in human neocortex and their relation to Alzheimer’s disease. Nat Commun. doi: 10.1038/NCOMMS14931
  2. Lim AS, Yu L, Schneider JA, Bennett DA, Buchman AS. Sleep fragmentation, cerebral arteriolosclerosis, and brain infarct pathology in community-dwelling older people. Stroke. 2016 Feb 1;47(2):516–8.
  3. Sohail S, Yu L, Bennett DA, Buchman AS, Lim AS. Irregular 24-hour activity rhythms and the metabolic syndrome in older adults. Chronobiol Int. 2015 Jan 1;32(6):802–13.
  4. Lim AS, Srivastava GP, Yu L, Chibnik LB, Xu J, Buchman AS, Schneider JA, Myers AJ, Bennett DA, De Jager PL. 24-hour rhythms of DNA methylation and their relation with rhythms of RNA expression in the human dorsolateral prefrontal cortex. PLoS Genet. 2014 Nov 6;10(11):e1004792.
  5. Lim AS, Kowgier M, Yu L, Buchman AS, Bennett DA. Sleep fragmentation and the risk of incident Alzheimer’s disease and cognitive decline in older persons. Sleep. 2013 Jul 1;36(7):1027–32.

Related News and Stories:

Related Links: