Recovery of arm motor function in the subacute phase after stroke. Aspects of assessment, treatment and neural reorganization

Abstract

Early after stroke, approximately two thirds of all patients experience impaired motor function of an arm impacting personal, social and occupational areas. The objective of this thesis was to examine different aspects of arm motor recovery in the subacute phase after stroke with regard to possible treatment alternatives. This was realized in three different studies: In the first study the recovery of arm motor function and the proportion of patients eligible for Constraint-induced movement therapy (CIMT) were examined in a longitudinal, repeated measurement design. In the second study two different treatment approaches for patients with mild to moderate paresis of an arm were compared in a randomized controlled trial. In the third study functional MRI was applied to study changes in potential mirror neurons after stroke and compared to healthy controls. The first study revealed that the number of patients regarded eligible for CIMT, according to defined motor criteria, constantly decreased during the first 3 months. Most patients with mild to moderate paresis regained satisfactory arm function, all receiving standard rehabilitation. In conclusion, it was proposed that CIMT should not be offered sooner than 4 weeks post stroke to patients with persisting motor deficits. No difference in change between the group receiving modified CIMT and the group receiving bimanual training was found in the second study. The results suggest that bimanual training may be as effective as modified CIMT in improving arm function in the subacute phase after stroke. In the third study changes over time in potential mirror neurons were found, concomitant with improvement of arm motor function. The activation of mirror neurons early and late after stroke and in healthy control subjects strengthens the notion that treatment approaches targeting those neurons may be a means of restoring arm motor function after stroke.