Kotomi Sakai,1,2 Enri Nakayama,3 Nicole Rogus-Pulia,4,5 Takahiro Takehisa,6 Yozo Takehisa,6 Kevin Y Urayama,2,7 Osamu Takahashi2 1Department of Rehabilitation Medicine, Setagaya Memorial Hospital, Tokyo, Japan; 2Graduate School of Public Health, St. Luke’s International University, Tokyo, Japan; 3Department of Dysphagia Rehabilitation, Nihon University School of Dentistry, Tokyo, Japan; 4Department of Medicine, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, USA; 5Geriatric Research Education and Clinical Center (GRECC), William S. Middleton Memorial Veterans Hospital, Madison, WI, USA; 6Heisei Medical Welfare Group, Tokyo, Japan; 7Department of Social Medicine, National Center for Child Health and Development, Tokyo, JapanCorrespondence: Kotomi SakaiDepartment of Rehabilitation Medicine, Setagaya Memorial Hospital, 2-30-10 Noge, Setagaya, Tokyo 158-0092, JapanTel +81-3-3703-5100Email koto.sakai1227@gmail.comPurpose: The objectives of this study were two-fold: 1) to investigate differences in activity duration and amplitude of the submental muscles during swallowing measured with surface electromyography (sEMG) in older patients with sarcopenic dysphagia compared to those without dysphagia and 2) to examine the diagnostic accuracy of submental sEMG signals for sarcopenic dysphagia.Patients and Methods: Patients (n = 60) aged ≥ 65 years participated in this cross-sectional study. The submental muscle activity duration parameters were the duration from the onset of swallowing to the maximum amplitude (duration A), duration from the maximum amplitude to the end of the swallowing activity (duration B), and total duration. The amplitude parameters were mean and maximum amplitude. Maximum lingual pressures were also measured for comparison with sEMG parameters.Results: Duration A was not significantly different between the groups (p = 0.15), but duration B (p < 0.001) and total duration (p < 0.001) were significantly different between the non-dysphagic and sarcopenic dysphagic groups. The mean (p = 0.014) and maximum (p < 0.001) amplitudes were significantly different between the groups. The area under the receiver operating characteristic curve (AUC) was 0.94 (95% confidence interval (CI) 0.87– 0.98) for duration B, 0.95 (95% CI 0.89– 0.99) for total duration, 0.76 (95% CI 0.63– 0.87) for maximum amplitude, and 0.61 (95% CI 0.47– 0.75) for mean amplitude. The AUC of the total duration was significantly greater than that of lingual pressure (p = 0.02).Conclusion: Patients with sarcopenic dysphagia had longer submental muscle activity duration and higher amplitude during swallowing as assessed using sEMG. The findings of this study can be useful in elucidating the underlying pathophysiology of sarcopenic dysphagia and in diagnosing sarcopenic dysphagia.Keywords: sarcopenia, deglutition disorders, electromyography, pharyngeal muscles
