Transcranial Direct Current Stimulation to Enhance Structured Language Therapy after Stroke

Aphasia, or impairment of language, is one of the most devastating problems after left hemisphere stroke, because it can interfere with an individual’s social interactions, ability to return to work, and even simple daily activities, such as returning email or answering the phone. Speech and language treatment can be helpful in restoring language function, but recovery is often incomplete. Recent studies indicate that the effectiveness of language treatment can be augmented by concurrent Transcranial Direct Current Stimulation (tDCS), a non-invasive, non-painful, electrical stimulation of the brain. It is believed that tDCS boosts neural plasticity that underlies recovery with language treatment. Beneficial effects have been shown in the chronic period (>6 months post-stroke), but the optimum time to apply tDCS with language treatment is unknown. In this study, we are exploring whether beneficial effects are also found in the acute-subacute period soon after stroke when neuroplasticity is greatest.

We are conducting a randomized, sham-controlled, double-blind trial. We are comparing the effects of anodal tDCS plus language treatment to sham plus language treatment. All participants receive 15 sessions of language therapy at no cost. During treatment sessions, half of the participants receive active tDCS, while the other half are fitted with the equipment that delivers tDCS but do not receive active stimulation. Neither the participant with aphasia nor the investigator will know whether the participant was randomly assigned to receive active tDCS until all participants have completed the study. Participants are evaluated before treatment as well as 1 week, 5 weeks, and 20 weeks after treatment. The primary outcome measure is change in picture naming accuracy. Participants who are willing and able to have MRI scans have brain scans that are used to study the effect of tDCS on brain activity. To be eligible, participants must enroll within 90 days of stroke.

The results of this study will help us better understand factors that influence recovery and will help us optimize speech and language therapy for people with aphasia after stroke.


We are actively enrolling participants with aphasia within 90 days of left hemisphere stroke.

Our colleague, Rajani Sebastian, is conducting a similar study looking at the efficacy of cerebellar tDCS plus language therapy in participants with chronic stroke (greater than 6 months after stroke). Click Here to learn more.

Funded by National Institutes of Health/National Institute on Deafness and Other Communication Disorders P50 DC014664

This study is part of the Center for the Study of Aphasia Recovery, a collaboration between researchers at the University of South Carolina, Johns Hopkins University, the University of California Irvine, and the Medical University of South Carolina.