Comparison of Geniohyoid Muscle Morphology Assessment Using Conventional and Handheld Ultrasound Devices

Point-of-care ultrasound has recently gained attention for enabling simple and immediate bedside assessments of swallowing function. In particular, handheld ultrasound devices (HHUDs) are more suitable than conventional ultrasound imaging systems (UISs) in community and home settings due to their portability. The geniohyoid muscle (GM) plays a crucial role in swallowing by contributing to hyolaryngeal elevation, and its dysfunction has been associated with aspiration risk. Therefore, ultrasound assessment of the GM provides clinically important information for evaluating swallowing function. This study aimed to evaluate GM morphology using a UIS and an HHUD and to investigate the relative and absolute reliability, as well as the correlation between the two devices.

GM morphology was assessed using a UIS and an HHUD by measuring the longitudinal diameter, longitudinal cross-sectional area, transverse vertical diameter, transverse lateral diameter, transverse cross-sectional area, and contraction percentage. Relative reliability was calculated using intraclass correlation coefficients (ICCs(1,3)), while absolute reliability was evaluated via Bland-Altman analysis to detect fixed and proportional bias. Pearson correlation coefficients and paired t-tests were used to compare measurements between devices.

High intrarater reliability (ICC > 0.9) was observed for all parameters except the contraction percentage. Bland-Altman analysis indicated fixed bias in longitudinal and transverse measurements. All parameters showed significant positive correlations between the UIS and HHUD, although the HHUD consistently yielded significantly smaller values.

HHUDs can be used for GM morphological assessment; however, clinicians should account for their tendency to produce smaller values compared to UISs. HHUD-based evaluation of the GM may have future applications in assessing sarcopenia-related dysphagia in older adults and in home-based clinical settings.