Intrasession and interrater reliability of rehabilitative ultrasound imaging measures of the deep neck flexors: A pilot study

The purpose of this investigation was to examine the intrasession and interrater reliability of rehabilitative ultrasound imaging (RUSI) to measure the deep neck flexors (DNF). Two investigators traced the DNF muscle borders in eight female subjects aged 33 ± 11.2 years. Of the eight subjects, five subjects reported a greater than 6-month history of neck pain, and three subjects were asymptomatic healthy controls. Cross-sectional area (CSA) (cm(2)) of right and left muscle groups were calculated. The intraclass correlation coefficients (ICC) for CSA measures were 0.67 (95% CI: 0.27-0.87) for rater 1 with a standard error of measurement (SEM) of 0.06 cm(2); 0.87 (95% CI: 0.65-0.96) for rater 2 with an SEM of 0.09 cm(2); and 0.68 (95% CI: 0.44-0.87) for interrater reliability between rater 1 and rater 2 with an SEM of 0.11 cm(2). The mean difference between CSA (cm(2)) measures were 0.00 ± 0.10 cm(2) for rater 1 and 0.09 ± 0.13 cm(2) for rater 2. The mean differences for CSA were 0.04 ± 0.12 cm(2). This pilot investigation suggests that RUSI could be used to reliably assess the size of the deep neck flexors.