Electrophysiological patterns of oropharyngeal swallowing in multiple sclerosis

Objective: We performed an electrophysiological study of swallowing (EPSS) in multiple sclerosis (MS) to describe oropharyngeal swallowing abnormalities and to analyze their correlations with dysphagia and with overall neurological impairment.

Methods: Neurological examinations were quantified using the Kurtzke Functional Systems and the Expanded Disability Status Scale (EDSS). Dysphagia was evaluated using the Dysphagia in Multiple Sclerosis (DYMUS) questionnaire, while fiberoptic endoscopic evaluation of swallowing (FEES) was used to establish the degree of aspiration and penetration, graded using the penetration-aspiration scale (PAS). The EPSS measured the duration of suprahyoid/submental muscle EMG activity (SHEMG-D), the duration of the laryngeal-pharyngeal mechanogram (LPM-D), and the duration of the pause in cricopharyngeal muscle EMG activity (CPEMG-PD); it also measured the interval between onset of the suprahyoid/submental muscle EMG activity (SHEMG) and onset of the laryngeal-pharyngeal mechanogram (I-SHEMG-LPM).

Results: 92% of patients showed at least one electrophysiological abnormality. I-SHEMG-LPM correlated positively with the DYMUS questionnaire. I-SHEMG-LPM, SHEMG-D, and DYMUS correlated positively with the PAS. Moderate to severe bladder sphincter dysfunction was associated with a significant reduction, or absence, of CPEMG-PD.

Conclusion: EPSS improves our understanding of the pathophysiology of dysphagia in MS.

Significance: This investigation could be useful in MS patients with swallowing abnormalities.