Ultrasound: Reliability of a Pocket-Sized System in the Assessment of Swallowing.

Purpose Ultrasound imaging offers a noninvasive adjunct to clinical swallowing assessment. Published reliability of sophisticated ultrasound systems is promising; however, no data exist for reliability using more affordable, pocket-sized devices. This study explored intrarater, interrater, and test-retest reliability of swallowing measures acquired with pocket-sized ultrasound technology. Method Five participants collected measures of swallowing from 20 healthy individuals using the Clarius ultrasound. Hyoid excursion and thyrohyoid approximation were derived during saliva, liquid, and puree swallowing. The cross-sectional area of the floor of mouth muscles and tongue thickness were obtained at rest. Measures were collected at two occasions minimum 11 days apart. Reliability was assessed for the entire process of data acquisition including scanning and online measurement, and for offline measurement of saved images. Results For most measures, reliability was poor (ICC [intraclass correlation coefficient] < .50) to moderate (ICC = .50-.75) for the entire process of data acquisition and poor to good (ICC > .75) when measuring saved images. Conclusion Further work is needed to elucidate whether our study findings apply to the Clarius system only or the data suggest a general limitation of pocket-sized ultrasound technology.

Classification of Stroke Patients With Dysphagia Into Subgroups Based on Patterns of Submental Muscle Strength and Skill Impairment.

OBJECTIVES: To identify and characterize subgroups of stroke patients with clinical signs of dysphagia, based on swallowing-related strength and skill impairments of the submental muscle group. DESIGN: Prospective observational study. SETTING: Inpatient rehabilitation centers and community dwellings. PARTICIPANTS: Individuals (N=114), including stroke patients with dysphagia (n=55) and 2 control groups including myopathic patients with dysphagia (n=19) and healthy volunteers (n=40) were included in this study. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Novel clinical assessment of strength (force generation) and skill (spatial and temporal precision of muscle activation) of the submental muscle group during swallowing and nonswallowing behaviors, using surface electromyography and dynamometry. RESULTS: Hierarchical cluster analysis revealed 4 clusters, which could be broadly characterized as cluster 1: intact strength and skill, cluster 2: poor strength and poor nonswallowing skill, cluster 3: poor strength, and cluster 4: poor strength and poor swallowing skill. Membership in cluster was significantly associated with medical diagnosis (P<.001). The majority of healthy and myopathic participants were assigned to clusters 1 and 3, respectively, whereas stroke patients were found in all 4 clusters. Skill outcome measures were more predictive of cluster assignment than strength measures. CONCLUSIONS: Although healthy and myopathic participants demonstrated predominantly homogeneous swallowing patterns of submental muscle function within their etiology, several subgroups were identified within stroke, possibly reflecting different subtypes of swallowing function. Future research should focus on the nature and rehabilitation needs of these subtypes. Assessment of skill in swallowing may be an important but overlooked aspect of rehabilitation.