Parents have always received advices from well-meaning family and friends not to let their children lie or sleep in one side or position all the time, because this habit will bring about skull flattening or deformation. Those who might have shrugged off the advice are possibly one of those now looking into or undergoing corrective helmet therapy for their baby.

Not so fast, though. Latest findings in a study indicate that a corrective helmet isn't that entirely beneficial at all.

Titled Helmet therapy in infants with positional skull deformation: randomised controlled trial, the study also defines what positional skull deformation is for further understanding among parents.

"Positional skull deformation is a condition in which the shape of an infant's skull deforms as a result of prolonged external forces," the study [pdf] states.

There are two kinds of positional skull deformation. One is plagiocephaly wherein flattened is one side of baby's head and the ears can get misaligned, too. The other is brachycephaly wherein flattened is the back of baby's head and possibly bulging is front of the skull.

Statistics from the study say that an estimate of one baby out of five who are below six months old develops such deformation. Babies' heads are prone to such deformation because their heads are still soft and growing quickly. The deformation has become common because of campaigns such as Back to Sleep that encourage parents to let babies sleep on their backs to minimize the risk of sudden infant death syndrome (SIDS). In fact, even the American Academy of Pediatrics (AAP) launched its own campaign in 1992 to encourage sleeping babies on their backs to reduce SIDS.

Since skull deformation is regarded generally as a cosmetic condition, many parents resort to corrective helmet therapy, which has been controversial issue since its inception. The National Health Service is not offering helmet therapy, reason why there are parents who pay for the treatment privately that costs around £2,000. In some countries like the Netherlands, the treatment is common with one to two percent of babies undergoing such therapy.

The researchers decided to conduct a HEADS study, considered as the first randomized trial analyzing the long-term impacts of the two approaches, because of the few research available on the corrective therapy as opposed to those who never received active treatment.

Involved in the study were 84 healthy full-term babies who suffered from moderate to severe plagiocephaly or brachycephaly. Half of these babies aged six months were selected randomly to wear the closely fitting, corrective helmet for 23 hours a day for six months. The remaining half of the participants received no such treatment.

The study reveals that the researchers found no significant difference in the skull shape of children at the age of two years old between those who underwent helmet therapy and those who didn't undergo such treatment. Although they showed parallel improvements, merely a quarter of them saw full recovery to a normal shape of the head.

Unfortunately, parents whose babies used the helmets given also reported side effects such as skin irritation, hindrance for cuddling time, unpleasant smell, sweating and pain.

Based on the conclusion of the researchers, the use of helmets are discouraged as standard therapy for healthy infants suffering from moderate to severe skull deformation, pointing to the high prevalence of side effects as well as high expenses attached to it.

The study was published by the British Medical Journal and funded by ZonMw, a Netherlands Organization for Health Research and Development.

The AAP also has similar findings in the Prevention and Management of Positional Skull Deformities in Infants study published [pdf] by Pediatrics in 2011, which indicate that such helmets are not necessary for most cases of plagiocephaly.

As expected, manufacturers of the corrective orthotic helmets argued the results of the recent study.

"The value of this research is fully reliant upon the quality of the fit," James Campbell, who is VP at the American Orthotic and Prosthetic Association, says to The New York Times.

Further research, however, suggests that parents should try every once in a while repositioning of the head of the baby when sleeping, to have more tummy time and to use baby carrier more and limit the use of car seats, instead of using corrective or orthotic helmets. Meanwhile, babies with tight neck muscles should also try physical therapy.