Prior COVID-19 Infection and Delayed Recall in Older Adults: A Pilot Study Relevant to AD/ADRD 

Jason Morin M.A., Yuekun (Hillary) Shao M.S., Catherine Kenney M.S., Mahmood Mohamed M.A., Sarah Curtis M.A., Shreya Upendra M.A., Romal Bhullar M.A., Spencer Xinyi Zhang M.A., Lili Liang M.S. MPH, Heng Chu M.S., WendyHuanyao Guo M.A., Amy Aloysi MD, Jeongyeon Hwang MD, Jessica Spat-Lemus Ph.D., Clara Li Ph.D. 

Background:  

Cognitive effects of COVID-19 in older adults remainincompletely characterized, particularly in diverse populations. Because episodic memory is central to Alzheimer’s disease and related dementias (AD/ADRD), we examined whether prior COVID-19 infection was associated with poorer delayed recall in older adults than in matched pre-pandemic controls. 

Methods: 

Participants were 100 adults aged 55 years and older with documented prior COVID-19 who were evaluated at the Icahn School of Medicine at Mount Sinai. Recruitment sources includedthe Mount Sinai Data Warehouse MyChart, the Mount Sinai COVID-19 Biobank, and referrals/flyers. Participants were compared with 400 demographically matched pre-pandemic controls from the National Alzheimer’s Coordinating Center (NACC) using propensity-score matching on age, sex, race/ethnicity, and education (4:1). The primary outcome was a harmonizedquintile-based verbal delayed recall measure derived from CRAFT story delayed recall in NACC and Consortium to Establish a Registry for Alzheimer’s Disease word-list delayed recall in the COVID-19 cohort.Montreal Cognitive Assessment (MoCA) served as a secondary screening measure. Prorating, scaling, and quintile-based approaches were examined as harmonization methods. Multivariable linear regression examined associations with delayed recall after partial demographic adjustment and full adjustment, including depressive symptoms measured by the Geriatric Depression Scale (GDS). 

Results: 

COVID-19 and control groups were balanced on matching variables; depressive symptoms were higher in the COVID-19 group (GDS: 3.21 [3.18] vs 1.91 [2.39], p<0.001). Prior COVID-19 infection was associated with worse delayed recall andremained significant after full adjustment (estimate = -0.37, 95% CI = (-0.65, -0.08), SE = 0.15, p = 0.012).  MoCA findings were inconsistent across harmonization methods and were notinterpreted. 

Conclusions: 

In this pilot sample, prior COVID-19 infection was associated with poorer delayed recall in older adults independent of demographic characteristics and depressive symptoms. Although baseline cognition, vascular risk factors, and ApoE4 status were unavailable, findings support further study of post-COVID memory changes and possible AD/ADRD vulnerability in diverse aging populations.