The longitudinal relationship between fatigue, mobility, and cognitive function in older adults with chronic stroke: secondary analysis of a randomized controlled trial

Abstract

AbstractBackgroundFatigue is a common consequence of stroke. Cross‐sectional evidence suggests post‐stroke fatigue is negatively associated with both mobility and cognitive function. We aim to understand the longitudinal relationship between fatigue, mobility, and cognitive function in community‐dwelling adults with chronic stroke (defined as having a stroke = or > 12 months prior to study).MethodsA secondary analysis of data from a 6‐month randomized controlled trial with 120 adults with chronic stroke who were randomized to group‐based, supervised: 1) exercise training; 2) complex social and mental activities; and 2) stretch and balance exercises with general education sessions. We constructed linear regression models to assess the contribution of changes in fatigue to changes in usual gait speed (over 4 meters) and to changes in cognitive function. Cognitive function was measured by the Alzheimer’s Disease Assessment Scale ‐ Cognitive Subscale (ADAS‐Cog) Plus. Higher ADAS‐Cog Plus scores indicate greater cognitive impairment. Fatigue was assessed using: 1) Fatigue Severity Scale; and 2) Visual Analogue Scale. The Fatigue Severity Scale measures fatigue severity and its impact on daily activities global fatigue The Visual Analogue Scale asks individuals to rate their global fatigue. Higher Fatigue Severity Scale and Visual Analogue Scale scores indicate greater severity and degree of fatigue, respectively. In the regression models, we controlled for experimental group, age, and biological sex.ResultsReduced severity of fatigue over the 6 months was associated with improved gait speed (p = 0.02). Reduced global fatigue was associated with improved cognitive function (p = 0.04). Specifically, a reduction of 25 points on the Fatigue Severity Scale was associated with an increase of 0.1 m/s in gait speed (R‐square = 5%). For the Visual Analogue Scale, a reduction of 3.3 points in global fatigue was associated with a reduction of 1 point (i.e., improvement) in the ADAS‐Cog Plus (R‐square = 4%).ConclusionsGiven the prevalence and consequence of fatigue on function in chronic stroke, future work is needed to identify effective interventions.