Standing balance strategies and dual-task interference are differentially modulated across various sensory contexts and cognitive tests in individuals with chronic stroke

Abstract

Background and Purpose: Mental tracking and verbal fluency tests have been linked to poor mobility and falls; however, no studies have examined the influence of imposing these tests on standing balance post-stroke. The purpose of this study was to investigate standing balance and cognitive performance across sensory conditions and cognitive tests post-stroke. Methods: Ninety-two participants with chronic stroke stood on dual-force platforms while performing various sensory conditions (eyes open/fixed surface, eyes closed/fixed surface, eyes open/swayreferenced surface, and eyes closed/sway-referenced surface) and cognitive tests (no cognitive test, serial subtractions, and verbal fluency). Equilibrium scores were computed based on the anteriorposterior sway angle. The number of correct verbal responses was recorded. Results: Performing serial subtractions during eyes closed/swayreferenced surface revealed the highest equilibrium score (64.0 ± 13.5), followed by the same sensory condition with added verbal fluency test (59.6 ± 15.1), followed by the single-task condition with no cognitive test (52.6 ± 20.9). The number of correct serial subtractions between seated (7.7 ± 3.7) and standing (7.2 ± 3.5) conditions was similar. A trend for more correct verbal fluency responses emerged when seated (8.1 ± 2.9) than the eyes open/sway-referenced surface condition (7.5 ± 2.8). Greater correct verbal fluency responses emerged when seated (8.6 ± 3.1) than the eyes closed/swayreferenced surface condition (7.8 ± 2.7). Discussion and Conclusions: Standing balance enhancement (higher equilibrium score/better balance) depends on the neuropsychological process targeted and the sensory input available poststroke. Cognitive dual-task interference emerged for the verbal fluency test during the most attention demanding sensory condition. Cognitive tests that enhance standing balance should be considered in assessments and interventions to evaluate and improve dual-tasking post-stroke. Video Abstract available for more insights from the authors (see the Video, Supplemental Digital Content 1, available at: http://links.lww. com/JNPT/A321).