Surface Electromyographic Activities of Submental and Infrahyoid Muscles: Comparisons Based on Residue, Penetration and Aspiration.

Background: Surface electromyography (sEMG) has been used in a wide range of studies conducted in the field of dysphagia.

Objectives: The main aim of this case-control study is to obtain how submental and infrahyoid sEMG signals differ based on residue, penetration and aspiration.

Methods: A total of 100 participants (50 patients with suspected dysphagia and 50 healthy controls) were enrolled in the present study. Participants with suspected dysphagia underwent a detailed fibreoptic endoscopic evaluation of swallowing (FEES) to observe the efficiency and safety of swallowing using the Yale Pharyngeal Residue Severity Rating Scale (YPRSRS) and the Penetration-Aspiration Scale (PAS), respectively. Afterward, sEMG parameters, including submental muscle activity duration (SMM-AD), infrahyoid muscle activity duration (IM-AD), amplitude of submental muscles (A-SMM) and amplitude of infrahyoid muscles (A-IM) were obtained during three consecutive dry swallows from all study cohorts.

Results: There were significantly higher SMM-AD values in patients with a YPRSRS score of 1-2 and a YPRSRS score of 3-5 for residue in vallecula compared to the controls (p < 0.001 and p = 0.001, respectively). Both subgroups of patients with a YPRSRS score of 1-2 and a YPRSRS score of 3-5 for residue in piriforms showed significantly higher SMM-AD values compared to the controls (p < 0.001 and p = 0.048, respectively). The same prolongation of SMM-AD was also evident for the patients with airway invasion (penetration or aspiration) compared to the controls (p = 0.042 and p < 0.001, respectively). The other measured sEMG parameters (IM-AD, A-SMM and A-IM) did not differ significantly based on FEES outcomes (p > 0.05).

Conclusion: Since the availability of instrumental swallowing assessment methods in clinical practice is quite challenging, specific sEMG parameters may be useful to predict possible residue, penetration, or aspiration events in patients with dysphagia. SMM-AD can be considered as a first-line assessment parameter for possible residue, penetration, and aspiration events before referring patients for further instrumental methods.