Head and Neck Muscle Activity in Post-Stroke Dysphagia Patients: Muscle Dynamics and Implications for Rehabilitation.

Background: This study utilised surface electromyography (sEMG) to evaluate the activity patterns of head and neck muscle groups in patients with post-stroke dysphagia (PSD), aiming to establish a scientific basis for muscle function rehabilitation in these individuals.

Methods: A case-control study, which involved 60 PSD patients and 60 healthy volunteers, was conducted between 1 August 2022, and 28 February 2024. The sEMG signals of head and neck muscles were recorded during dry swallowing and various phonatory tasks, including pursed-lip breathing (PLB), end-inspiratory breath holding (EIBH), lip trills and the pronunciation of the sounds /a/, /n/ and /m/. The mean sEMG amplitude of each muscle group during these tasks was measured and analysed.

Results: For the PSD patients, the sEMG signal of the masseter muscle (MS) during dry swallowing was significantly correlated with its signal recorded during all tasks except PLB. Similarly, the sEMG signal of the orbicularis oris muscle (OO) during dry swallowing showed significant correlation with its signal during PLB, /a/ and /n/ tasks, whereas for the submental muscle (SUB), significant correlation existed across all tasks. In the healthy controls, the sEMG signal of MS and OO during dry swallowing did not correlate significantly with their signals recorded during any task, whereas for SUB, significant correlation existed between the sEMG signal during dry swallowing and the signals recorded during lip trill, /a/, /n/ and /m/ tasks. Across all subjects, the sEMG signal of the sternocleidomastoid muscle (SCM) during dry swallowing was significantly correlated with its signal recorded during all tasks. According to multiple regression analyses, the following tasks affected certain muscle groups in the patients but not in the controls: lip trills on MS, SUB and SCM, pronouncing /a/ on OO and pronouncing /n/ on SCM.

Conclusion: For the PSD patients, there were varying levels of muscle activation in head and neck muscles during different phonatory tasks. Carefully selecting phonatory tasks may help develop targeted rehabilitation strategies.