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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 Focus:

  • 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:

Research in Dr. Lim's laboratory has three foci:

1. Investigation of the epidemiological, genetic and pathophysiological links between sleep and circadian disruption, and the development of neurological outcomes such as cognitive impairment, dementia and stroke. This research demonstrates that sleep fragmentation predisposes older individuals to the development of incident cognitive decline and Alzheimer's disease (Lim et al., Sleep, 2013), and that sleep fragmentation modifies the impact of the ApoE4 allele on the risk of incident Alzheimer's disease and neurofibrillary tangle pathology (Lim et al., JAMA Neurology, 2013).

Techniques used in this research are mathematical analysis of physiological signals to extract sleep and circadian phenotypes (e.g., probabilistic state transition analysis); linear mixed models; survival analysis; and large cohort (1000+ individuals), noninvasive ambulatory sleep and circadian assessment (e.g., actigraphy, ambulatory sleep apnea assessment

2. Investigation of circadian rhythms of gene expression and epigenomic modification in the human cerebral cortex. This research demonstrates that daily rhythms of clock gene expression are detectible in postmortem human cerebral cortical tissue, and that there are sex differences in the entrained phase of these rhythms (Lim et al., Journal of Biological Rhythms, 2013).

Techniques used in this research are circadian analysis of human neocortical transcriptomic and epigenomic data analysis.

3. Investigation of the genetic determinants of human sleep and circadian traits. This project seeks to identify common genetic variants influencing human sleep and circadian traits, elucidate potential mechanisms of action, and apply this knowledge to the prediction of human sleep and circadian traits in clinical settings. Recent results include identification of the first common genetic variant to be associated with the circadian timing of human behavioural rhythms and with clock time of death (Lim et al., Annals of Neurology, 2012).

Techniques used in this research are genome-wide association study of quantitative traits, and large-cohort (1000+ individuals), non-invasive ambulatory sleep and circadian assessment (e.g., actigraphy, ambulatory sleep apnea assessment).

Individuals interested in fellowship, graduate or undergraduate positions in the laboratory are encouraged to apply by email.

Selected Publications:

See current publications list at PubMed.

  1. Lim AS, Yu L, Kowgier M, Schneider JA, Buchman AS, Bennett DA. Modification of the relationship of the apolipoprotein E ε4 allele to the risk of Alzheimer disease and neurofibrillary tangle density by sleep. JAMA Neurology. 2013 Oct 21 2013. [Epub ahead of print].
  2. 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.
  3. Lim AS, Myers AJ, Yu L, Buchman AS, Duffy JF, De Jager PL, Bennett DA. Sex difference in daily rhythms of clock gene expression in the aged human cerebral cortex. J Biol Rhythms. 2013 Apr;28(2):117–29.
  4. Lim AS, Chang AM, Shulman JM, Raj T, Chibnik LB, Cain SW, Rothamel K, Benoist C, Myers AJ, Czeisler CA, Buchman AS, Bennett DA, Duffy JF, Saper CB, De Jager PL. A common polymorphism near PER1 and the timing of human behavioral rhythms. Ann Neurol. 2012 Sep;72(3):324–34.
  5. Lim AS, Moro E, Lozano AM, Hamani C, Dostrovsky JO, Hutchison WD, Wennberg RA, Lang AE, and Murray BJ. Selective enhancement of REM sleep by deep brain stimulation of the human pons. Ann Neurol. 2009 Jul; 66:110–114.

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