Most of the time, corrective helmets do not help babies who have flat head syndrome, according to research published recently on bmj.com.

There was no significant difference in skull shape at the age of two years between children treated with helmet therapy and those who received no active treatment.

Approximately 20 percent of babies under the age of six months develop a skull deformation as a result of lying in the same position for long periods. Flat head syndrome has become more common since the launch of campaigns to encourage parents to place their babies on their backs to sleep to lower the risk of sudden infant death syndrome (SIDS).

While helmet therapy is a controversial treatment for positional skull deformation or plagiocephaly, it is a popular practice in some countries. For example, one to two percent of all babies have helmet therapy in the Netherlands.

Researchers found 84 healthy full-term babies who had a moderate or several positional skull deformation. Half of the babies were given helmet therapy for 23 hours a day for a six-month period, beginning at the age of six months. The other half received no active treatment.

At the age of two, measurements of their shape revealed there was no meaningful variation in the degree of improvement in skull shape between the two groups. Researchers found that 25.6 percent of babies who had helmet therapy had a full recovery at two years of age, versus 22.5 percent of those who had no active treatment.

All the parents whose babies wore a helmet noted side-effects, including skin irritation, a foul smell, sweating and pain.

Interestingly, the parents of both groups were generally satisfied with their child’s head shape at two years of age.

“Based on the effectiveness of helmet therapy, and the high prevalence of side-effects and high costs, we discourage the use of a helmet as a standard treatment for healthy infants with moderate to severe skull deformation,” write the researchers.

Despite the findings, researchers contend that parents should continue to place their babies on their backs to sleep to lower the risk of SIDS.