Impact of neck percutaneous interferential current sensory stimulation on swallowing function in patients with Parkinson's disease: A single-arm, open-label study protocol.

Background: Parkinson's disease (PD) can lead to swallowing dysfunction, resulting in aspiration pneumonia. Among the types of swallowing disorders, a characteristic and serious problem associated with PD is silent aspiration due to pharyngeal and laryngeal hypoesthesia. Methods: This single-arm, open-label study aims to evaluate the effectiveness of percutaneous neck interferential current sensory stimulation in enhancing swallowing function in patients with PD. The efficacy and safety of percutaneous neck interferential current sensory stimulation will be investigated for patients diagnosed with PD, based on the Movement Disorder Society criteria, of Hoehn-Yahr stages 2-4. The patients will receive neck percutaneous interferential current sensory stimulation for 20 min twice a week for 8 weeks using a Gentle Stim® (FoodCare Co., Ltd., Kanagawa, Japan) device. Once the intervention is initiated, evaluations will be performed every 4 weeks for a 16-week period. The primary endpoint to be assessed is the proportion of patients with normal cough with 1% citric acid at the end of the intervention (8 weeks after intervention initiation) compared with that at the beginning. This clinical trial will examine the usefulness of percutaneous neck interferential current sensory stimulation in patients with PD. In addition, this study will use novel instruments, such as multichannel surface electromyography and electronic stethoscope, to evaluate swallowing function. Discussion: This novel evaluation can provide insights into dysphagia in patients with PD and the usefulness of percutaneous neck interferential current stimulation. This exploratory study is limited by its single-arm, open-label design and small size. Trial registration number: jRCTs062220013; pre-results.