Intra- and inter-rater reliability for analysis of hyoid displacement measured with sonography.

Objective: Anterior hyoid displacement is essential for efficient swallowing and is usually investigated with videofluoroscopy. Ultrasound offers a less expensive and noninvasive method of investigation. The present study investigated the viability of a novel method of quantifying hyoid displacement from sonograms using an anatomic reference point, through an evaluation of inter- and intra-rater reliability.

Methods: Three raters reviewed the sonographic video sweeps of five discrete swallows from each of five participants for inter-rater reliability. The primary investigator measured each swallow on two occasions for intra-rater reliability. Electronic calipers were used to measure distances from a "rest" frame prior to the swallow of interest and a "maximal displacement" frame, at which the hyoid bone was at maximal anterior displacement during each swallow.

Results: Single-measure intraclass correlation coefficient was high for inter-rater agreement at 0.86 for rest measures and 0.86 for maximal displacement. Intra-rater reliability was even higher at 0.95 for rest and 0.98 for maximal displacement.

Conclusions: These preliminary results suggest that by using a novel analysis approach involving an anatomic reference point, raters can achieve high agreement on measurement of position of hyoid at maximal displacement relative to rest.