Combination of Transcranial Direct Current Stimulation and Action Imitation Training in Post- Stroke Aphasia Rehabilitation: Implications from a Single Case Study.

Abstract

Background. One of the most used non-invasive brain stimulation (NIBS) techniques in aphasia rehabilitation is Anodal Transcranial Direct Current Stimulation (A-tDCS). Its application is supported by the fact that brain plasticity, when facilitated by language intervention, can be improved by non-invasive brain stimulation. The effects of neuromodulation combined with various language and communication therapies have led to promising results in the rehabilitation of patients presenting with acquired aphasia. An Action Observation Therapy such as IMITAF seems to contribute to improvements in language skills, mainly in naming. This experimental clinical protocol aims to investigate the rehabilitative potential of A-tDCS on perilesional areas, combined with computerized neuropsychological training. Method. Participant: Mr. V., 66-year old right-handed male, Italian native speaker. The patient suffered an ischemic stroke due to left carotid artery dissection which resulted in right hemiparesis, mixed transcortical aphasia, characterized by non-fluent speech and dysarthric and disfluent speech. Treatment: The subject underwent unipolar montage stimulation, with anode placed in F5 and intra-cephalic reference on Fp2. For safety reasons, a stimulation intensity of 1.5 mA was applied for 20 minutes once a day in combination with IMITAF level I, which required the subject to repeat bisyllabic words. Procedure: The stimulation protocol lasted a total of 4 weeks and was divided into 2 different modes. Clinical Training: 40-minute treatments (no.10 sessions) and involved the combined administration of a-tDCS (20-minute online mode) and 40-minute training. Home-Based Training: 40-minutes trainig carried out at the patient’s home, via PC (no. 8 sessions). Results. Mr. V. completed the protocol treatment sessions without reporting any adverse effects, such as scalp redness, tingling or headache. The results showed an improvement in the auditory/visual comprehension of words/sentences after A-tDCS and Action Observation Therapy, which has maintained one month after treatment. Conclusions. Together with IMTAF neuropsychological training, the constant and repeated use of A-tDCS, on the perilesional areas, contributed to improvements in language skills thus promoting an overall recovery of communicative skills in an individual with chronic post-stroke non-fluent aphasia.