Cerebellar tDCS enhances functional communication skills in chronic Aphasia

BackgroundTranscranial direct current stimulation (tDCS) has emerged as a possible neuromodulatory tool to augment language therapy in post-stroke aphasia. However, there is limited information on whether tDCS may help to improve everyday functional communication.AimsTo investigate whether cerebellar tDCS combined with computerized aphasia treatment improves functional communication skills in individuals with chronic aphasia.Methods and ProceduresIn a randomized, double-blind, sham-controlled, within-subject crossover study, participants received 15 sessions of anodal (n = 14) or cathodal (n = 14) cerebellar tDCS plus computerized aphasia treatment then sham plus computerized aphasia treatment, or the opposite order. Linear mixed-effects regression models were performed to evaluate (1) the effect of tDCS treatment on change in functional communication skills on the two dimensions of the American Speech-Language-Hearing Association Functional Assessment of Communication Skills for Adults (ASHA-FACS): Communication Independence (CI) scale and Qualitative Dimension of Communication (QDC) scale, and (2) the relationship between functional communication skills and trained and untrained naming abilities.Outcomes and ResultsThe results showed significant tDCS-induced gains for the overall QDC mean score, but not for the overall CI mean score. Cerebellar stimulation was more effective than sham for the overall QDC mean score immediately post-treatment, 2-weeks post-treatment and 2-months post-treatment. Follow up analysis separated by group showed that the change in the overall QDC mean score (combining both phases) were similar in participants receiving anodal or cathodal stimulation. We also found a significant linear association between the ASHA-FACS overall CI mean change scores and trained and untrained naming change scores for the tDCS condition but not sham.ConclusionsOur study provides preliminary evidence that cerebellar tDCS coupled with computerized aphasia treatment has the potential to improve the overall qualitative dimensions of functional communication skills in individuals with chronic aphasia.Clinical Trial RegistrationCerebellar Transcranial Direct Current Stimulation and Aphasia Treatment [NCT02901574]