Relationship Between Swallowing Muscle Morphology and Dysphagia in Patients Followed With Stroke

Dysphagia is frequently seen in stroke patients. Although various factors have been identified as negative predictors of dysphagia recovery, swallowing muscle atrophy has also been emphasized.

The aim of this study was to examine the swallowing muscles in stroke patients with or without dysphagia using ultrasound (US), to determine the predictors on swallowing function and to identify independent predictors of dysphagia.

Patients with stroke were evaluated. Mini Nutritional Assessment-Short Form (MNA-SF), Functional Oral Intake Scale (FOIS), Eating Assessment Tool (EAT-10) and Functional Independence Measure (FIM) were assessed. The thicknesses of masseter, temporal and mylohyoid muscles, and cross-sectional areas of geniohyoid and digastric anterior muscles were measured.

A total of 42 stroke patients were included. The patients with dysphagia were older (p = 0.004). MNA-SF, FOIS, and FIM scores were lower in the dysphagia group (p < 0.001). Muscle measurements decreased on the hemiplegic side in the digastric anterior muscle of the dysphagia group (p = 0.032). Hemiplegic side masseter muscle thickness (p = 0.011), non-hemiplegic side masseter (p = 0.021) and mylohyoid muscle thicknesses (p = 0.005), digastric anterior cross-sectional area (p = 0.017) were lower in the dysphagia group. Multivariate logistic regression analysis showed that lower MNA-SF scores were associated with a higher probability of dysphagia (OR = 0.734, p = 0.048).

Although swallowing muscles were affected in post-stroke dysphagia, a muscle group that predicts dysphagia has not been identified. MNA-SF was independently related to dysphagia; however, the observed association should be considered within the bidirectional framework. The assessment of swallowing muscles by US and the identification of affected muscles can improve the development of targeted rehabilitation programs.