Babies whose skulls are deformed from lying in the same position for extended periods do not benefit from the use of corrective helmets, according to findings from a new randomized study.

Renske M. van Wijk, a PhD candidate from the Department of Health Technology and Services Research, Institute for Innovation and Governance Studies, University of Twente, Enschede, the Netherlands and colleagues present their findings in the May issue of BMJ.

Positional plagiocephaly (unilateral occipital flattening of the skull) and brachycephaly (symmetrical occipital flattening) affect about a fifth of infants and often trigger referral to craniofacial centers.

The prevalence of skull deformation rose steeply after health authorities began recommending infants be placed on their backs to avoid sudden infant death syndrome, the researchers note.

The use of rigid, custom-made helmets aimed at correcting such deformations has also risen. However, that practice has been controversial, and until now, little research has been devoted to evaluating the use of helmets vs doing nothing.

With an eye on filling that gap, the researchers designed a randomized controlled trial to evaluate results using helmet therapy. They identified 84 full-term infants who had moderate to severe skull deformation. The infants were randomly assigned at about 6 months of age to receive either helmet therapy or no therapy.

The researchers instructed parents of infants who received helmets to have their children wear the helmets 23 hours each day until they were a year old or until skull abnormalities were normalized.

When the babies reached 2 years of age, the researchers took detailed measurements of the babies' heads and found no significant difference in improvement of skull shape between babies who had worn helmets and those who had not. About 26% of babies who had worn helmets fully recovered their skull shape compared with about 23% who had not. The researchers said that difference did not reach statistical significance.

Helmet use was associated with numerous problems, including skin irritation (96%), parents being hindered from cuddling their child (77%), unpleasant odor (76%), increased sweating (71%), and perceived pain (33%).

"Based on the equal effectiveness of helmet therapy compared with the natural course, the high prevalence of side effects and the high costs of treatment, we discourage the use of helmet therapy as a standard treatment for healthy infants with moderate to severe skull deformation," they conclude.

The researchers emphasize that because only about a quarter of babies in either group fully recovered from abnormalities, prevention is key. The best approach was placing the child in varied positions during waking hours while sticking to tummy-up recommendations when the baby was asleep.

In an editorial accompanying the study, Brent R. Collett, PhD, assistant professor of psychiatry and behavioral sciences, University of Washington School of Medicine, Seattle, said that future studies encompassing larger samples would help determine whether some infants might respond more favorably than others to use of corrective helmets.

"In particular, it would be of interest to learn whether children with the most severe positional plagiocephaly and brachycephaly, who were excluded from this trial, show meaningful improvement," he notes.

This work was supported ZonMw, the Netherlands Organization for Health Research and Development. The authors and the editorialist have disclosed no relevant financial relationships.

BMJ. Published online May 1, 2014.