Reliability of still photography measuring habitual head deviation from midline in infants with congenital muscular torticollis.

PURPOSE: To establish intrarater and interrater reliability of still photography for measuring habitual head deviation from midline in infants with congenital muscular torticollis (CMT).

METHODS

Two investigators took still photographs of 30 infants with CMT in a supine position and measured head deviation angles with a protractor. Data analysis included paired t tests, Pearson r, and intraclass correlation coefficients (ICC) with 95% confidence intervals.

RESULTS

Pearson r varied from 0.80 to 0.85 for the same rater and from 0.72 to 0.99 for 2 different raters. The ICC (3,1) varied from 0.79 to 0.84, and ICC (2,1) varied from 0.72 to 0.99. Participants with smaller head-tilt angles showed greater variability in head position.

CONCLUSIONS

Still photography is a reliable method for measuring habitual head deviation from midline in infants with CMT. Several modifications to the measurement procedure have been suggested.