Indirect causal path from motor function to quality of life through daily use of the affected arm poststroke after task-specific training: a longitudinal mediation analysis

Purpose: Task-specific training generally targets motor function, with the ultimate goal of improving quality of life (QoL). This study aimed to determine whether motor function indirectly affects QoL through daily use of the affected arm and activities of daily living (ADL) in patients with chronic stroke. Methods: This was a retrospective cohort study of 155 patients who received training for 90–120 min/session, 3–5 sessions/week, for 4–6 weeks. The training involved specific mirror or robot-assisted therapy, followed by functional task practice for 15–30 min in each session. Patients were assessed before and after the intervention. Results: At both pre-test and post-test, significant indirect effects of motor function on QoL through daily use of the affect arm and ADL were observed (β = 0.087–0.124). When the change scores of the measures between the pre-test and post-test were used, significant mediating effects of daily arm use on the relationship between motor function and QoL were identified (β = 0.094–0.103). Conclusions: Enhanced motor function after intervention may lead to an increase in arm use for daily activities and subsequently result in an improvement in QoL. These results highlight the critical role of daily arm use in task-specific training aimed at improving QoL.