Effects of Repetitive Transcranial Magnetic Stimulation in Aphasic Stroke

Abstract

Although functional imaging studies suggest that recruitment of contralesional areas hinders optimal functional reorganization in patients with aphasic stroke, only limited evidence is available on the efficacy of noninvasive brain stimulation such as repetitive transcranial magnetic stimulation aimed at suppression of contralateral overactivation. In this randomized, controlled, blinded pilot study, the effect of 1-Hz repetitive transcranial magnetic stimulation over right-hemispheric Broca homolog in subjects with poststroke aphasia in the subacute stage was examined. According to their group allocation, patients received, in addition to conventional speech and language therapy, multiple sessions of repetitive transcranial magnetic stimulation either over the right-hemispheric inferior frontal gyrus (intervention group) or over the vertex (control group). The primary outcome parameter was the change in laterality indices as quantified by activation positron emission tomography before and after the 2-week intervention period. The clinical efficacy was evaluated with the Aachen Aphasia Test. At baseline, no group differences were discovered for age, laterality indices, or mean Aachen Aphasia Test scores. Four patients were lost to follow-up, but none due to side effects of the transcranial magnetic stimulation. Positron emission tomography revealed an activation shift toward the right hemisphere in the control group (P=0.0165), which was absent in the intervention group. Furthermore, the latter improved significantly clinically by a mean of 19.8 points in the Aachen Aphasia Test total score (P=0.002), whereas the control group did not. There was however no clear linear relationship between the extent of laterality shift and clinical improvement (r=0.193, P=nonsignificant). Repetitive transcranial magnetic stimulation might be an effective, safe, and feasible complementary therapy for poststroke aphasia.