Comparison of the Effect of Four Transcranial Direct Current Stimulation Configurations on Picture-Naming Improvement in Non-Fluent Aphasia: A Randomized Clinical Trial

Abstract

Background: Anomia is a language disorder that negatively affects communication abilities in people with aphasia (PWA). We aimed to compare the effect of transcranial direct current stimulation (tDCS) over the left and right inferior frontal gyrus (IFG) and superior temporal gyrus (STG) on the picture-naming accuracy and reaction time in PWA.Methods: A randomized, single-blind, sham-controlled crossover trial was conducted in 2021 at Mobasher Kashani Clinic, Hamadan, Iran. Sixteen patients received both five days of real-tDCS (1 mA for 20 minutes) and five days of sham-tDCS with a seven-day washout period in between. Using the Persian aphasia naming test, picture-naming accuracy and reaction time on 50 images were assessed at baseline, real-tDCS, and sham-tDCS stages. The data were analyzed using STATA software, version 11.0. P<0.05 was considered statistically significant.Results: Sixteen non-fluent PWA participated in the study. Of all patients, 64% benefited from tDCS over the STG and 18% over the IFG. The results showed that real-tDCS had a significant effect on the picture-naming accuracy (P=0.003) and the Persian-Western aphasia battery-one score (P=0.01), whereas sham-tDCS had no noticeable effects. Both the real- and sham-tDCS had no significant effect on the reaction time (P=0.28).Conclusion: Five sessions of individualized tDCS protocol (1 mA for 20 minutes) were adequate to improve picture-naming accuracy in patients with chronic aphasia.

Keywords

• transcranial direct current stimulation
• aphasia
• anomia
• reaction time