Comparison between swallowing-related and limb muscle involvement in dermatomyositis patients

To determine the relationship between the movement of the hyolaryngeal complex and the motor power of limb muscles and the differences in the hyolaryngeal movement according to the creatine kinase (CK) levels in dermatomyositis patients.

We retrospectively selected 13 patients who had undergone a videofluoroscopic swallowing study (VFSS) for swallowing difficulty from patients diagnosed with dermatomyositis. The maximal anterior and superior displacements of the hyoid and larynx and the cricopharyngeal opening were acquired by frame-by-frame analysis using the VFSS. We investigated the motor power of the bilateral shoulder abductor, elbow flexor, hip flexor, and knee extensor muscles to determine the limb muscle involvement and used the American Speech-Language-Hearing Association (ASHA) National Outcomes Measurement System (NOMS) swallowing level (ASHA level) to assess dysphagia severity. Spearman's correlation test was used to identify the relationship between the kinematic data of the laryngeal structures, ASHA levels, and the total motor scores in dermatomyositis patients.

There was no significant correlation between the kinematic data of the laryngeal structures, ASHA levels, and total motor scores. Only the anterior movements of the hyoid and larynx had a significant relationship to the upper oesophageal sphincter opening.

Dysphagia evaluation should be considered separately in dermatomyositis patients irrespective of limb involvement or dysphagia severity because the swallowing-related muscle involvement had no relationship to the limb muscle involvement or the severity of dysphagia in dermatomyositis. It is hoped that our results can be used to evaluate the therapeutic effects of dysphagia management in dermatomyositis patients.