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The Brain Resilience Study: Circadian rhythm amplitude is associated with cognitive performance in older adults

Poster Session B - Sunday, March 8, 2026, 8:00 – 10:00 am PDT, Fairview/Kitsilano Ballroom
Also presenting in Data Blitz Session 3 - Saturday, March 7, 2026, 10:30 am – 12:00 pm PST, Salon E.

Stephanie R. U^1,2, Kelly Shen², Tegan Soroka¹, Kashish Mehta¹, Aina Roenningen¹, Ralph E. Mistlberger¹, Parveen Bhatti^3,4, Anthony R. McIntosh^1,2, Brianne A. Kent^1,2; ¹Simon Fraser University, ²Institute of Neuroscience and Neurotechnology, Simon Fraser University, ³The University of British Columbia, ⁴British Columbia Cancer Research Institute

People with Alzheimer’s disease (AD) often experience changes to their circadian rhythms, including altered behavioural patterns (e.g. ‘sundowning’), reduced robustness of rest-activity cycles, and loss of suprachiasmatic nucleus (SCN) neurons. However, the role of circadian rhythm disruption in the etiology of AD remains understudied. Among 52 adults aged 53-84 years, we assessed cognitive function with the Montreal Cognitive Assessment (MoCA), and we collected 14 days of wrist actigraphy (ActiTrust 2, Condor Instruments, Sao Paulo, Brazil) to assess the rest-activity daily rhythm. Urine and saliva samples were also collected consecutively every three hours for 48-hours to measure markers of endogenous circadian rhythms driven by the SCN (urinary aMT6s and salivary cortisol). Participants who had a MoCA total score <26 were classified as “At Risk” for dementia, and exhibited rest-activity circadian rhythms with lower amplitude than participants performing >26 on the MoCA (t(33.260) = 2.660, p = 0.012, η² = 0.175). Data analysis of the biosamples is ongoing. These results suggest that lower circadian amplitude is associated with mild cognitive impairment. Pending longitudinal evaluations, reduced amplitude could serve as an early biomarker of dementia vulnerability. This research aims to deepen our understanding of circadian dynamics in understanding mechanisms of cognitive resilience in aging.

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