RECENT research from the Karolinska Institutet in Stockholm has shed light on the complex relationship between cognitive reserve and stress, revealing that stress may undermine the neurocognitive benefits of cognitive reserve in patients at memory clinics. Cognitive reserve, a concept developed by neuropsychologist Yaakov Stern, refers to the brain’s ability to compensate for damage and maintain cognitive function, influenced by factors such as education, occupational complexity, and engagement in physical, social, and leisure activities. The study explored whether cognitive reserve could mitigate cognitive decline and how stress might influence this relationship.
The researchers focused on 113 participants from the Cortisol and Stress in Alzheimer’s Disease cohort (Co-STAR) study, examining the associations between a composite measure of cognitive reserve—termed the Cognitive Reserve Index (CRI)—and cognitive performance, alongside Alzheimer’s disease-related biomarkers. Participants were assessed on various neuropsychological tests, including memory, processing speed, working memory, and perceptual reasoning. They also provided data on their education, occupational complexity, and social and leisure activities, which were used to calculate CRI scores. Additionally, subjective stress levels were recorded, and physiological stress was measured through diurnal salivary cortisol levels.
The findings revealed that higher CRI scores were linked to better cognitive performance both at baseline and over a three-year follow-up period. However, when cortisol levels were accounted for, the positive impact of cognitive reserve on cognition was reduced, suggesting that physiological stress may weaken the protective effects of cognitive reserve. Interestingly, no significant associations were found between CRI scores and Alzheimer’s disease biomarkers.
These results underscore the potential for stress to compromise the cognitive benefits associated with enriching life experiences. The study’s authors emphasise the need for effective stress management strategies as part of dementia prevention efforts, highlighting the importance of maintaining both cognitive stimulation and stress reduction to promote optimal cognitive health.
Laith Gergi, EMJ
Reference
Yerramalla MS et al. Cognitive reserve, cortisol, and Alzheimer’s disease biomarkers: a memory clinic study. Alzheimers Dement. 2024;0(7):4486-4498.
