Application of non-invasive brain stimulation with the use of repetitive transcranial magnetic stimulation (rTMS) or transcranial direct current stimulation (tDCS) in the treatment of dysphagia following an ischemic stroke – analysis of research reports

Stroke is one of the significant problems and causes of death, in particular in highly developed countries. It is also the most common cause of dysphagia.
This study is devoted to the analysis of publications from the last decade concerning research on the use of non-invasive brain stimulation (TMS, tDCS) in the treatment of dysphagia following an ischemic stroke. The following databases were searched for publications: PUBMED, Polish Scientific Journals Database, EBSCO, ScienceDirect. Out of 358 articles found, only two met all the inclusion conditions.
The studies discussed in this article included patients who had their first unilateral ischemic stroke, followed by dysphagia.
Findings from pilot studies on the effectiveness of the use of tDCS in the treatment of dysphagia following an ischemic stroke were analysed. Fourteen patients aged 50-92 were randomly assigned to two groups. The study group was treated with anodic stimulation, and the control group with sham brain stimulation. The results showed that patients in the study group obtained a statistically significant result, indicating an improvement in the swallowing function as measured by the Dysphagia Score and Severity Scale. The above data may indicate the effectiveness of the use of tDCS in the treatment of dysphagia.
Fifty patients were qualified for the research on the effectiveness of rTMS in the treatment of dysphagia. Three groups were created: the first group treated with high frequency rTMS, where patients received rTMS stimulation – 3Hz; the second group with low frequency rTMS – 1Hz; and the control group. The effectiveness of the therapy used was assessed on the fifth day and after 1, 2 and 3 months. After 5 days the groups where active rTMS stimulation was used showed greater improvement in the swallowing function compared to the sham stimulation group. Improved results in the Standardized Swallowing Assessment were also recorded after 3 months in the 1Hz and 3Hz groups, but this did not apply to the control group. In three groups, the results of the water swallow test and the degree of dysphagia improved after 3 months.
This analysis shows that non-invasive brain stimulation using tDCS and rTMS in the treatment of dysphagia is associated with improved swallowing function. However, the small number of studies conducted in this area does not allow for extrapolation of their results.