Clinical classification of deformational plagiocephaly according to Argenta: a reliability study

The incidence of deformational plagiocephaly (DP) in primary health care is increasing. Patients are referred and treated by different practitioners. However, reliable and practical assessment tools in clinical practice are lacking. The clinical classification according to Argenta distinguishes 5 types of DP based on severity of asymmetry of the skull, ear position, and face. The aim of this study was to investigate the reliability of this clinical classification of DP. Twenty referred patients aged 0 to 1 year were classified for DP. Raters from 3 different professions (3 infant health care physicians, 3 pediatric physiotherapists, and 3 manual therapists) were used because these professionals are the first ones who see children with DP in clinical practise. Interrater and intrarater reliability was determined for the type of DP (I-V) and each characteristic clinical feature separately. There was a moderate overall interrater agreement for classifying DP (mean weighted kappa, 0.54), whereas intrarater agreement ranged from 0.60 to 0.85, indicating substantial to almost perfect agreement. Kappa scores of the first 4 clinical features of DP (occipital flattening, ear malposition, frontal bossing, and facial asymmetry) ranged from 0.45 to 0.57 for the interrater reliability and 0.47 to 1 for the intrarater reliability, except for 1 score of -0.14. Agreement for the fifth feature (vertical skull growth) was due to chance (kappa approximately 0). The classification according to Argenta is a moderately reliable method for classifying DP in clinical practice.