Introduction: Previous studies indicate that anodal transcranial Direct Current Stimulation (A-tDCS) to left hemisphere or cathodal tDCS (C-tDCS) to right hemisphere might augment aphasia therapy to facilitate language recovery after chronic stroke and that cerebellar tDCS can augment verbal fluency and learning in healthy controls.
Hypothesis: A-tDCS or C-tDCS) plus naming therapy results in improved naming performance for trained and untrained items from baseline to post-treatment compared to sham plus naming therapy in chronic aphasia.
Methods: Six patients with large, chronic left middle cerebral artery (MCA) ischemic stroke and one patient with large bilateral MCA strokes participated in a randomized, double-blind, sham controlled, within-subject crossover trial (15 sessions of sham + naming therapy and 15 sessions of tDCS + naming therapy, in random order, separated by 2 months). 4 patients were randomly assigned to A-tDCS and 3 patients were assigned to C-tDCS. We used 2 mA for stimulation over right cerebellum for the first 20 minutes of computer-delivered naming therapy. Within-subjects within-treatments analysis using McNemar’s test for correlated responses to evaluate gains from each of the treatment conditions. An alpha level of p<0.05 was considered significant.
Results: tDCS + naming treatment produced significant gains in naming of both trained and untrained items in 3/4 patients with anodal stimulation and 3/3 patients with cathodal treatment. Sham + naming treatment produced gains for only trained items, and only in 4/7 participants.
Discussion: A-tDCS or C-tDCS improved generalization of improvements to untrained stimuli after naming therapy for most patients. Results indicate potential usefulness of right cerebellar tDCS to augment naming therapy after chronic post stroke aphasia with large left or bilateral lesions.