Head asymmetry, otherwise known as positional plagiocephaly or deformational plagiocephaly, is the change to the normal shape of a baby’s head. It means a misshapen, flat, or uneven head shape. It’s very common in infants, but if left untreated it may change their physical appearance, and even increase the risk of neurodevelopmental delays.
But, what makes it happen? It is believed that flattening of the head in one area may happen if a baby lies with their head in the same position for prolonged periods. The bones of a newborn’s skull are thin and flexible, so the head is soft and can gradually change shape, resulting in asymmetrical development.
Why does a baby prefer certain positions? Recent studies of infants with plagiocephaly showed that 90% were found to have restrictions in neck motion.
Previously, plagiocephaly was believed to be merely cosmetic in nature, but more recent evidence is actually suggesting otherwise. There are many studies that have shown increased risks of neurodevelopmental delay in infants with moderate to severe head asymmetry – typically seen as delays in reaching milestones such as crawling or sitting, and talking – of up to 40%.
And of more serious concern, this delay may actually continue right through to school ages with very recent evidence again finding those with moderate to severe asymmetry present.
Our body has many receptors – think of the senses like smell and taste – that provide our brain with feedback of what is going on in the world around us. One of these senses is called proprioception, and it is how we know where our body is in space. This sense of proprioception is one of the biggest stimulators of the brain, and very much helps drive brain development.
Do you know why babies usually start talking around 12 months of age? It’s because they have just started walking. Getting upright and resisting gravity activates receptors in our spine, which then gives the brain that surge to jump to the next level of development.
This is why the neck is important. In our body, the upper part of the neck has the most dense population of proprioception receptors. Could a change in neck motion then disrupt the stimulation that drives brain development? There is plenty of evidence of neck dysfunction influencing brain activity, but it requires further research.
Improving early motor development may aid the delays seen in infants with head asymmetry, and this is one of the key aims that health professionals in the musculoskeletal field such as chiropractors, osteopaths and physiotherapists are working towards: increasing motion within a restricted neck.
This may be done by employing a series of stretches, or releases on muscles or joints within the neck. We may promote more active tummy time to help activate neck muscles, or even using special pillows to position the head while your baby is laying on their back. It is important to note that while sleeping on the tummy may promote improvement in head shape, it is not advised under 6 months of age as it may also increase SIDS risk.
One of the easiest ways is by looking straight down from the top. Is the back of the head a nice rounded shape, or does there appear to be a flattening of either the very back or one side? Maybe you can see one ear drifting forwards compared to the other side?
It is important to get your child’s head shape assessed, and this is typically done during routine Child Health/Well Child Check appointments with your Child Health Nurse, to ensure it is a positional plagiocephaly and not a more serious condition causing changes to head shape. Early intervention with your health professional may not only aid in correcting the shape of your child’s head, but also improve their future development.
* I have previously recorded a YouTube video on this topic, you are welcome to link this in but only if you feel it is appropriate: https://youtu.be/YV8o7z9PZBI