Öhman A. Inter rater and intra rater reliability of the modified severity scale for assessment of plagiocephaly, among physical therapists. Physiotherapy Theory Practice 2011 early online, 1-5.
Infants with congenital muscular torticollis (CMT) are at risk of developing skull asymmetry. The aim of this study was to investigate the inter-rater and intra-rater reliability of a modified “severity scale for assessment of plagiocephaly” among physical therapists (PT). Thirty-nine members of a network of PTs working with infants with CMT participated in the study. Photos of infants were used in this study. They were taken from above (superior view) to estimate posterior flattening and forehead asymmetry, and from the front (anterior view) to estimate neck involvement and facial asymmetry. The photos were coded and sent to the PTs together with instructions and a protocol for estimation. A second estimate was carried out with the same photos in a different order. The PTs also answered questions concerning their experience of CMT and the scale used. The participants had worked as PTs for an average of 20 years, and with CMT for an average of 7 years. The inter-rater reliability kappa was 0.71, and the intra-rater reliability was mean 0.68. Intra-rater reliability was significantly higher for years of experience and for years working with CMT. There was no significant impact on reliability in relation to how many infants the PTs usually examine yearly, whether they found the scale easy to use, or how much experience they had using it. In conclusion, the modified “severity scale for assessment of plagiocephaly” has satisfying statistical agreement. Reliability is affected by the number of years of experience of the PTs.