Digital Image Motion Analysis of the Pharyngeal Movement during Swallowing in Dysphagia Patients

Objective: To reveal basic mechanism regarding the swallowing difficulty in stroke and inflammatory myopathy patients, and to compare this with normal persons. Method: Five volunteers without any swallowing problems, three inflammatory myopathy patients and five stroke patients with swallowing difficulty and a similar movement of the hyoid bone were included in this study. Videofluoroscopic swallowing studies were performed in all subjects, and their videofluoroscopic motions were analyzed through 2-dimensional motion analysis using the APAS (Ariel Performance Analysis System). Results: The motions of the hyoid bone and the epiglottis of the inflammatory myopathy patients were much smaller than those of the volunteers but their pattern was similar to the volunteers. Although the difference in the displacement of the hyoid bone and epiglottis between the stroke patients and volunteers was low, the movement pattern between them was different. During an excursion of the hyoid bone, there was an interruption in its motion, which may be due to the spasticity of the cricopharyngeal muscle. Conclusion: In inflammatory myopathy patients, the cause of the dysphagia is a weakness of the swallow-related muscles but in stroke patients, spasticity of the upper esophageal constrictor muscle, i.e. the cricopharyngeal muscle, may be another cause. Relieving the spasticity of the cricopharyngeal muscle as well as strengthening of the swallow-related muscles should be considered when treating stroke patients with dysphagia.