The effect of transcranial direct current stimulation paired with neuromuscular electrical stimulation on swallowing function in post stroke dysphagia

Transcranial direct current stimulation (tDCS) and neuromuscular electrical stimulation (NMES) are noninvasive neuromodulation techniques that have shown positive effects in a variety of neurological disorders. Most protocols apply one modality at a time. Here we tested the effect of tDCS applied together with NMES on patients with dysphagia after acute stroke. To assess the efficacy of combined tDCS and NMES on improvement of dysphagia after acute stroke, guided by Fiber-optic endoscopic evaluation of swallowing (FEES). This study is a double-blinded randomized case-controlled study conducted in a University hospital. This study enrolled 48 patients diagnosed by FEES and assigned to 3 groups of 16 patients each. The first group received both tDCS and NMES, the second group received NMES only and the third group received sham NMES. Gugging Swallowing Screen (GUSS) test was done before and after intervention.

Significant improvement was seen in all tested materials on GUSS test in tDCS/NMES group. While in the other two groups, there was only improvement for safety of liquid swallowing.

This study shows that the combined application of tDCS and NMES has an advantage in improvement of PSD over active NMES and sham NMES groups in all materials tested by GUSS.