What Happens to Swallowing Muscles after Stroke?: A Prospective Randomized Controlled Electrophysiological Study

Abstract

Background: Stroke is the most frequent reason of neurological dysphagia Electrophysiological studies can be used to evaluate oral, pharyngeal and initial phase of esophageal phase.

Aims: This study aims to noninvasively evaluate mastication, mimic, and tongue muscles of stroke patients, which play an important role in the oral phase of swallowing process and compare them with healthy individuals.

Setting and design: This study was conducted at the Physical Medicine and Rehabilitation Clinic of our hospital between January 2014 and December 2016.

Materials and methods: Fifty-one patients who were admitted to our clinic with stroke and 51 healthy individuals were evaluated for the study. Demographic features of individuals were recorded. The swallowing intervals and motor action potentials (MAPs) of trigeminal, facial and hypoglossal nerves were measured. After four weeks of treatment schedule, patients were re-evaluated.

Statistical analysis: The Wilcoxon Signed Rank test, the Mann-Whitney U test and Fisher exact test were used in this study.

Results: The all swallowing intervals were found prolonged compared to the healthy controls (P < 0.05). The MAPs of the masseter, orbicularis oculi, and intrinsic tongue muscles were significantly lower in patient group (P < 0.05). After treatment, we found significant improvement for all parameters in patient group, but the swallowing intervals were still significantly prolonged, and MAPs of these muscles were still lower (P < 0.05).

Conclusion: Although swallowing is examined as different phases, the process is complicated and should be evaluated totally. In post-stroke dysphagia, oral phase of swallowing process is as important as phayngeal phase and perioral, mastication, and tongue muscles are influenced even in an early period as a month.

Keywords: Dysphagia; electrophysiology; stroke; swallow muscles.