The evaluation of the transcranial direct current stimulation efficacy on conduction aphasia

Aphasia is a language disorder effecting many people today. Aphasia syndromes, which can develop as a result of cerebrovascular and neurodegenerative events, can be encountered in many ways. Conductive aphasia is characterized by paraphasic speech, difficulty in object naming and repetition. Transcranial direct current stimulation (tDCS) is a technique that is frequently used in clinics for treatment purposes and in scientific studies for research purposes. The aim of this study is to increase the synaptic plasticity of perilesional region cells in patients via effecting cell excitation. Therefore, double-blind, control grouped and between-group experimental design with pre and post-test sessions was used in the study. While 10 patients received real anodal stimulation, 10 patients received sham stimulation five times in consecutive days. The evaluation was performed with the patients before the first day, after the fifth day of stimulation and after one month follow-up study. With this effect, aphasic individuals who took the real stimulation were expected to decrease in the number of paraphasia with increased object naming and repetition. According to the results, the paraphasia rate in active group during object naming task decreased significantly compared to sham stimulation and there was no significant difference between two groups in correct response rate. However, the average score of active group increased compared to sham group. There was no significant difference in repeatation ability. These results support the idea that tDCS may have an impact on widely seen language disabilities especially paraphasia and naming task and it can be considered as a treatment in conduction aphasia. Key Words: conduction aphasia, transcranial direct current stimulation, naming task, repetition skill, paraphasia