Dynamic interactions between impairment and activity after stroke: examining the utility of decision analysis methods

Objective: To examine the utility of decision analysis methods for examining the dynamic nature of impairment-activity interactions following stroke. Design: Decision analyses (Chi-squared Automatic Interaction Detector) of a prospective cohort study. Setting: Community and institutional settings based on the location of participants three months after stroke. Participants: Individuals were recruited from consecutive admissions to a regional academic health center and were assessed three months after stroke (N=67). Main outcome measures: Neurological impairment was measured with the National Institutes of Health Stroke Scale (NIHSS). Mobility, self-care and instrumental activities of daily living (instrumental ADL) performance were assessed with a performance observation measure, the Performance Assessment of Self-care Skills (PASS). Decision analysis methods were used to examine interactions between neurological impairments and activity outcomes. Results: Unique neurological impairments were associated with each activity outcome (bowel and bladder urgency interacted with mobility; hand function interacted with self-care; mental functions interacted with instrumental ADL), and these findings are supported by previous studies. The predictive validity of mobility and self-care analyses was stronger than the instrumental ADL analyses. Conclusions: Decision analysis methods show promise for understanding dynamic impairment-activity interactions. This understanding may enhance methods for informing rehabilitation decisions.