Improved picture naming in aphasia patients treated with cathodal tDCS to inhibit the right Broca's homologue area.

PURPOSE

Previous reports have suggested that noninvasive cortical stimulation could influence speech production in patients with chronic stroke. Here, we evaluated the hypothesis that cathodal transcranial DC stimulation (ctDCS), a technique that decreases excitability of stimulated cortical sites, applied over a healthy right Broca's homologue area could improve picture naming in patients with post-stroke aphasia.

METHODS

Ten right-handed patients with post-stroke aphasia were enrolled in this double blind, counterbalanced sham-controlled, crossover study. Each patient received an intervention of ctDCS (2 mA for 20 min) and of sham tDCS (2 mA for 1 min) daily for 5 consecutive days in a randomized crossover manner with a minimum interval of one week between interventions, over a healthy right Broca's homologue area using a left supraorbital anode and simultaneous daily sessions of conventional word-retrieval training. The primary endpoint measure of this study was a standardized, validated Korean version of the Boston Naming Test, which is a measure of picture naming skills.

RESULTS

ctDCS was not found to have any adverse effects. Furthermore, significantly improved picture naming (p = 0.02) was observed at 1 hour following the last (5th) ctDCS treatment session, but no changes were observed after sham tDCS.

CONCLUSION

These results demonstrate that cathodal tDCS over the right healthy Broca's homologue area with a left supraorbital anodal location can improve picture naming task performance in post-stroke aphasia.