Motor recovery from constraint induced movement therapy is not constrained by extent of tissue damage following stroke.
Purpose: The purpose of this study was to delineate the relationship between several types of T1-weighted MRI pathology and motor rehabilitation potential following Constraint Induced Movement therapy (CI therapy) in chronic stroke. Methods: Stepwise regression was employed (n= 80) to identify predictors of motor recovery (prior to therapy) and of response to Constraint-Induced Movement therapy [measured via the Wolf Motor Function Test (WMFT) and Motor Activity Log (MAL)] from among the following: age, side of motor deficit, chronicity, gender, lesion volume, peri-infarct damage volume, white matter hypointensity volume, ventricular asymmetry, and lesion location. Results: Although extent of total stroke damage weakly correlated with poorer performance on the WMFT prior to therapy, this relationship was mediated by the location of the damage. No metric of tissue damage examined here was associated with real-world arm use at baseline (MAL at pre-treatment) or with CI therapy-induced improvement in either best motor performance upon request (WMFT) or spontaneous arm use for daily activities (MAL). Conclusions: In sum, the extent of brain tissue damage of any type examined here poorly predicted motor function and response to rehabilitation in chronic stroke.