Relationship Between Swallowing Dynamics and Suprahyoid Muscle Activity in Sarcopenic Dysphagia

To investigate sarcopenic dysphagia characteristics and the relationship between suprahyoid muscle activity and swallowing dynamics using concurrent surface electromyography (sEMG) and videofluoroscopic swallowing study (VFSS). 56 elderly (≥ 65 years) with possible sarcopenia were prospectively enrolled and classified into aspiration (Penetration Aspiration Scale [PAS] ≥ 6, n = 27) and non-aspiration (PAS < 6, n = 29) groups. Swallowing dynamics (Videofluoroscopic Dysphagia Scale [VDS]) and suprahyoid sEMG activity were evaluated concurrently during 2 ml water swallows. Mean and maximum sEMG amplitudes showed no significant differences between 2 groups. However, total (p = 0.035) and peak-to-end (p = 0.008) durations were significantly longer in the aspiration group. Adjusted multivariable linear regression analysis revealed that prolonged peak-to-end duration was significantly associated with higher total VDS (B = 0.007, p = 0.015), pharyngeal VDS (B = 0.009, p = 0.019), and VDS aspiration sub-item scores (B = 0.030, p = 0.005). Receiver operating characteristic (ROC) curve analysis showed that a peak-to-end duration cutoff of 1.64 s predicted aspiration with a specificity of 93.1%, an area under the curve of 0.71, and a diagnostic odds ratio of 14.54 (95% CI 2.87-73.66). Aspiration in possible sarcopenic dysphagia appears to be more closely associated with prolonged suprahyoid muscle contraction-deactivation duration, suggesting a slowing of the overall contraction process rather than impaired contraction amplitude. Peak-to-end duration measured by sEMG showed modest-to-moderate discrimination with high specificity for identifying aspiration risk, suggesting a potential role in the early screening of patients who may require further evaluation and targeted swallowing rehabilitation.