Do Midlife Motivational Abilities Predict Cognitive Decline and Alzheimer's Disease?

Motivational reserve (MR) is a form of brain reserve and can be defined as a set of motivational abilities that provide the individual with resilience to neuropathological damage. In two studies, the hypothesis was tested that lower premorbid motivational abilities are associated with higher risk of cognitive impairment and Alzheimer’s disease (AD). Premorbid motivational abilities of the participants were estimated on the basis of the individual occupational history using the Occupational Information Network (O*NET) database which provides detailed information on worker characteristics. A previous study has shown that O*NET-based premorbid motivational abilities correlate highly significant with established self-report measures of motivational abilities. Cross-sectional study: In a community sample of 147 non-demented participants aged 60-94 years, 10% were mildly cognitively impaired. Motivational abilities predicted odds of mild cognitive impairment, even when age, sex, education, and premorbid cognitive ability (“cognitive reserve”) were controlled (OR 0.24; 95% CI 0.08-0.71). Longitudinal study: In the German Study on Ageing, Cognition and Dementia in Primary Care Patients (AgeCoDe), about 2500 non-demented participants aged 75-89 were followed up twice (after 1 1⁄2 and 3 years). In a fully adjusted model, motivational abilities were associated with a reduced risk of MCI. The association of midlife motivational abilities with incidence of AD was less clear. Midlife motivational abilities were associated with reduced risk of AD in ApoE e4 carriers, but not in non-carriers. Revealing the mechanisms underlying this association of motivational abilities and cognitive decline may lead to novel strategies for delaying the onset of AD symptoms.