The influence of cognitive reserve on Alzheimer's disease progression

Abstract

AbstractBackgroundThe incidence and prevalence of Alzheimer’s disease (AD) continues to rise in the growing elderly population putting public health at increased economic, healthcare, and caregiving burdens. The effects of AD pathology on the brain are irreversible, making it hard to determine effective treatment after symptom onset. Primary prevention has been proven to reduce the risk of developing AD later in life. Past research found that cognitive reserve (CR), an individual’s ability to cope with brain changes, impacts AD risk. The buildup of CR over a life span has shown positive cognitive implications. However, the influence that CR has on the rate of AD progression remains to be explored. This study used a survey tool that accounts for all CR proxies to explore this gap.MethodTo quantify CR in the study population of 90 AD participants, the Cognitive Reserve Index questionnaire was used. The Clinical Dementia Rating scale was utilized to stage AD progression. One‐way ANOVA and Independent Samples T‐tests were used to test for differences between the mean CR scores of dementia groups. One‐way ANOVA was also used to test for differences between CR level groups and mean number of days it took to transition from one dementia stage to the next. Multivariable linear regression was utilized to determine the unit change in time associated with an increase in CR score.ResultThere was not a significant difference in mean CR score by dementia group (F = 1.96, p = 0.15). After collapsing the moderate and severe dementia groups to compare to the mild dementia group, there was a significant difference in mean CR score (mild mean (SD) = 131(15.0), moderate/severe mean (SD) = 123(20.6), p = 0.05). After controlling for physical activity, for every unit increase in CR score, the number of days for transitioning from mild to severe dementia increased by 34 days (β = 33.94, 95% CI: 8.07, 59.81, p = 0.01).ConclusionHigher CR was associated with slower AD progression. This indicates that consistent engagement in activities that promote CR buildup over a life span are methods for improving AD and dementia health outcomes.