Transcranial Direct Current Stimulation Does Not Improve Language Outcome in Subacute Poststroke Aphasia

Abstract

Background and purpose: The aim of the present study is to investigate the effect of transcranial direct current stimulation on word-finding treatment outcome in subacute poststroke aphasia.

Methods: In this multi-center, double-blind, randomized controlled trial with 6-month follow-up, we included 58 patients with subacute aphasia (<3 months poststroke), who were enrolled in a stroke rehabilitation program. Patients participated in 2 separate intervention weeks. Each intervention week included 5 daily sessions of 45-minute word-finding therapy combined with either anodal transcranial direct current stimulation (1 mA, 20 minutes; experimental group) or sham transcranial direct current stimulation (control group) over the left inferior frontal gyrus. The primary outcome measure was the Boston Naming Test. Secondary outcome measures included naming performance for trained/untrained picture items and verbal communication.

Results: Both the experimental (n=26) and the control group (n=32) improved on the Boston Naming Test over the intervention period and 6-month follow-up; however, there were no significant differences between groups. Also for the secondary outcome measures, no significant differences were found.

Conclusions: The results of the present study do not support an effect of transcranial direct current stimulation as an adjuvant treatment in subacute poststroke aphasia.

Clinical trial registration: URL: http://www.trialregister.nl/trialreg/admin/rctview.asp. Unique identifier: NTR4364.

Keywords: aphasia; electric stimulation; neuronal plasticity; stroke rehabilitation; treatment outcome.