Multiple sclerosis (MS) is a chronic neurodegenerative autoimmune disease of the central nervous system. Apathy is significantly higher in adults with MS compared to healthy populations. Apathy is a lack of motivation that can cause dysfunctions in each step of goal-directed behaviors. Apathy is associated with diminished ability to perform activities of daily living, tasks requiring normal executive function, and quality of life. Across various neurodegenerative disorders, apathy has been regarded as a predictor of poor cognition and functional outcomes. However, the severity of apathy and its association with cognitive function in older adults with MS have not been reported. This study's objective was to address this gap of knowledge. Hence, we evaluated: 1) the severity of apathy symptoms in older adults with MS compared to healthy older adults and, 2) the association of apathy symptoms and global cognitive functioning in older adults with MS compared to controls.

Participants were community-residing older adults (age >60ys) enrolled in a cohort study, “Brain Predictors of Mobility and Falls in Older Adults with Multiple Sclerosis.” Healthy controls (n=59; mean age=66.25± 3.37; %female=47.5) and persons with MS (n=69; mean age=64.58± 3.88; %female=62.3) were included in the analysis. Using McDonald criteria, MS diagnosis was physician-confirmed by medical record review, apathy symptoms were assessed through 4 apathy symptom questions on the 30-item Geriatric Depression Scale (GDS), and global cognitive functioning was assessed using the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). Covariates included age, gender, years of education, global health score (GHS), and depression (GDS w/out apathy questions). For the first objective, a linear regression model was used with a bi-level group status variable (MS vs controls) serving as a predictor of apathy symptoms. For the second objective, two linear regression models stratified by group status were run with apathy symptoms as a predictor of global cognitive functioning.

The presence of MS was significantly associated with worse apathy (β=.34, p < .001) and it remained significant after adjusting for covariates (β=.19, p=.03). Additionally, apathy was negatively associated with global cognition in persons with MS (β=-.32, p =.01) and this association remained significant after adjusting for covariates (β=-.33, p =.01) except depression (β=-.27, p =.08). The association of apathy and global cognitive functioning was not significant in healthy controls (β=.01, p=.95).

This study is the first to report worse apathy symptoms in older persons with MS compared to healthy controls. Additionally, worse apathy symptoms were associated lower global cognitive functioning in older adults with MS but not in healthy controls.