Exploring the association between physical activity and cognitive function among people living with dementia

Background Physical activity preserves cognitive function in people without dementia, but the relationship between physical activity and cognitive domains among people living with dementia is unclear. Objective The objective of this study was to explore the association between physical activity and cognition domains among people living with dementia. Methods Participants living with dementia in residential care facilities (complete case analysis: n = 24/42) completed a battery of cognitive tests (global cognition: Montreal Cognitive Assessment; executive function: Trail-Making Test, Digit Span Forward Test; perception and orientation: Benton Judgement of Line Orientation Test; language: Boston Naming Test; learning and memory: Rey Auditory Verbal Learning Test; complex attention: Digit Symbol Substitution Test). Participants wore an actigraphy monitor on their non-dominant wrist over seven days. We conducted a linear regression for total physical activity (independent variable) with race (white/black), fall risk (Morse Fall Scale), and the number of comorbidities (Functional Comorbidities Index) as covariates, and cognitive tests as variables of interest. Results Participants were primarily male (75%), white (87.5%), and 50%had unspecified dementia (Alzheimer's disease: 33%). Greater physical activity was associated with poorer global cognition, better executive function, and better learning and memory (ps < 0.05). Physical activity was not related to visuospatial perception, language, or complex attention. Conclusions Physical activity may preserve executive function and learning and memory among people living with dementia. Wandering is more common in later stages of dementia, which may explain greater physical activity observed with lower global cognition. Regularly assessing physical activity may be useful in screening and monitoring cognitive changes.