Cranial Orthosis Therapy for Plagiocephaly: an RCT Pilot Study Comparing Cranial Orthosis to the Natural Course

Inclusion Criteria: * All participants must be assessed by a physiatrist at Sainte-Justine Hospital at the plagiocephaly clinic of the physical medicine and rehabilitation service. * Participants must have a clinical diagnosis of severe deformational plagiocephaly by a physiatrist based on clinical evaluation and confirmed by anthropometric measurements with a spreading caliper and 3D-scan. * Participants must be aged from 4 months and 0 days to 7 months old minus a day at the onset of cranial orthosis therapy. Premature subjects will be age-adjusted by calculating the post-partum age minus the number of weeks of prematurity, rounding to the whole nearest month. * Participants' parents (or legal guardian) must be apt to give consent and able to reliably express themselves (either written or verbally, if illiterate or unable to write for any other reason). Exclusion Criteria: * Patients whose 3D-scan measurements do not confirm a severe plagiocephaly. * Participants who are lost at follow-up or who drop out of treatment will be excluded. * Participants whose parents report less than 20 hours per day on average of helmet wear. * Participants with synostotic cranial deformation. * Patients with isolated brachycephaly, without a plagiocephalic component to the deformation. * Patients with other craniofacial deformities or syndromes. * Patients having had their orthosis made or modified at a laboratory other than the Sainte-Justine hospital/Centre de réadaptation Marie-Enfant.