Cerebellar tDCS enhances functional communication skills in chronic Aphasia

ABSTRACT

Background

Transcranial 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.

Aims

To investigate whether cerebellar tDCS combined with computerized aphasia treatment improves functional communication skills in individuals with chronic aphasia.

Methods and Procedures

In 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 Results

The 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.

Conclusions

Our 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 Registration

Cerebellar Transcranial Direct Current Stimulation and Aphasia Treatment [NCT02901574]

KEYWORDS:

• Cerebellar tDCS
• stroke
• aphasia
• functional communication
• language therapy

Acknowledgments

We extend our thanks to the individuals with aphasia who participated in the study. We thank Dr. Gayane Yenokyan and Jiafeng Zhu from the Johns Hopkins Biostatistical Center for their assistance with statistical analysis.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data Availability Statement

The data that support the findings of this study are available from the corresponding author, [RS], upon reasonable request.

Supplemental data

Supplemental data for this article can be accessed online at https://doi.org/10.1080/02687038.2024.2328874

Correction Statement

This article has been corrected with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was supported by the National Institutes of Health (National Institute of Deafness and Other Communication Disorders) [K99/R00DC015554, R56/R01DC019639, P50DC014664, R01DC005375]; and the Johns Hopkins University COVID-19 Bridge Grant. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health; NIH/NIDCD.