Dose response of task-specific upper limb training in people at least 6 months poststroke: A phase II, single-blind, randomized, controlled trial.

Objective: 1) Determine if higher doses of motor therapy in chronic post-stroke hemiparesis result in better outcomes compared to lower doses, and 2) Evaluate potential modifiers of the dose-response relationship. Methods: Eighty-five adults with UE paresis  ≥  6 months after stroke were randomized to one of four dose groups in this single-blind, parallel, RCT. The dosing parameter manipulated was amount of task-specific training, as indexed by the number of task repetitions. Groups received 3200, 6400, 9600, or Individualized Maximum (IM) repetitions, during 1 hr sessions, 4 days/week for 8 weeks. The intervention was an individualized, progressive task-specific upper limb training program designed to improve upper limb functional motor capacity. The primary outcome was the slope of the Action Research Arm Test (ARAT) during the intervention. Effects of dose and potential modifiers of the dose-response relationship were evaluated with hierarchical linear models. Results: ARAT scores for the 3200, 9600, and IM groups improved over time as indicated by slopes (ΔARAT/wk, mean ± SEs) of 0.40 ± 0.15, 0.31 ± 0.16, and 0.66 ± 0.14, respectively (p < 0.05). The slope of the 6400 group was smaller (-0.05 ± 0.15) and significantly different from the 3200 and IM groups (p < 0.001). Initial motor capacity, neglect, and other tested characteristics did not modify the dose-response relationship. Interpretation: Overall, treatment effects were small. There was no evidence of a dose-response effect of task-specific training on functional capacity in people with long-standing upper limb paresis post stroke. This article is protected by copyright. All rights reserved.