Monitoring Spontaneous Swallowing After Tracheostomy Using a Neck-Worn Electronic Stethoscope: A Pilot Study

Background/Objectives: Reduced spontaneous swallowing frequency (SSF) may reflect dysphagia. In this study, SSF was evaluated using a neck-worn electronic stethoscope (NWES), certified as a medical device in Japan, with artificial intelligence support in patients undergoing tracheostomy. Methods: This single-center observational study included tracheotomy patients who underwent swallowing assessment with an NWES between August 2024 and July 2025. Several variables were evaluated, including tracheostomy cannula cuff status and dietary status, assessed using the Functional Oral Intake Scale (FOIS). The Mann-Whitney U-test was applied, with SSF (/min) measured over 10 min using an NWES as the primary objective variable. Furthermore, Spearman's correlation analysis was performed to examine the relationship between SSF (/min) and the pharyngeal saliva retention grade, which was determined using the Hyodo score during fiberoptic endoscopic evaluation of swallowing (FEES). Results: Eighteen patients who underwent tracheotomies were included in this study. SSF (/min) increased significantly when the tracheostomy cannula cuff was deflated (p = 0.049) and when the feeding status was FOIS ≥ 3 (p = 0.032) or FOIS ≥ 4 (p = 0.014). Spearman's correlation analysis revealed a negative correlation between SSF (/min) and the pharyngeal saliva retention grade (ρ = -0.68, p = 0.0019). Conclusions: SSF measured with an NWES tended to increase with improved swallowing function, which is consistent with the outcomes of previous reports. The SSF measurement method used in this study may prove to be a useful clinical tool.