Head Asymmetry (Plagiocephaly)

What causes head asymmetry? 

Head asymmetry can be evident from birth in about 13% of babies due to in utero molding of the shape of the baby’s head; however, if this occurs, there is in most cases rapid correction of the baby’s head shape soon after birth. Most cases of head asymmetry occur in babies born with a normal shaped head, and the head asymmetry develops after birth, usually becoming apparent to the parents or to a health care professional between four and eight weeks of age. The head asymmetry usually affects one side of the occipital bone or the back of the head.  

The issue of head asymmetry has become more common as a result of the baby on the back program to reduce the incidence of SIDS. The head asymmetry is caused by constant pressure on one part of the back of the head, and this tells us that the baby is not able to turn their head properly to both sides, resulting in positional preference. Babies that develop head asymmetry have been found to have a positional preference and to also have restricted neck function. Many babies that go on to develop head asymmetry have associated torticollis, and may have a sternocleidomastoid muscle tumour along with contraction of this muscle. To avoid this you can seek help from Clinic 27


What is the cause of plagiocephaly or head asymmetry?  

The link between positional preference and plagiocephaly was explored by Miller and Clarion. They found that 84% of their 174 patients born with normal head shape and subsequently developed occipital plagiocephaly, had associated torticollis. The development of head asymmetry affecting the back of the head (occiput) was shown to be associated with significant upper cervical spine issues in most patients. This relationship had been earlier demonstrated by Slate and colleagues who evaluated 30 infants for congenital muscular torticollis, and found that 26 of these patients had occipital plagiocephaly, 13 of whom exhibited rotary subluxation of C1 of C2 with computerised tomographic (CT) scanning. 

This research indicates that at least half of the patients with head asymmetry affecting the back of the head, have clinically significant upper cervical spine subluxation. Our clinical experience indicates that most of the cases we see with occipital plagiocephaly have a subluxation affecting the upper cervical spine. Chiropractors specialise in and are specifically trained to correct this type of tissue when it affects the cervical spine. 


What is long term effect of plagiocephaly or head asymmetry? 

Prior to the year 2000 the general opinion within the medical community was that there were no long term issues with head asymmetry. It was regarded as just a matter of giving the head shape time to correct, and if there was still an issue with the head shape when the child was older, then it was silly a matter of growing the hair to cover the head asymmetry. The issue was felt to be only a cosmetic problem requiring no treatment or management.  

This belief was shown to be incorrect as a result of research conducted by Miller and Clarion which was published in 2000. Miller et al long at long term outcomes in patients with deformational occipital plagiocephaly, which is where the back of the head becomes flat.  

They found that 39.7% of the children with persistent deformational plagiocephaly had received special help in primary school. Only 7.7% of siblings required similar help. Problems noted, related to subtle problems of cerebral dysfunction that were manifest during the school age years involving language disorders, learning disability and attention deficits. 

Unfortunately, many within the medical community are unaware of this research, and continue to regard occipital plagiocephaly as a cosmetic issue, requiring no treatment or management. Chiropractors understand the importance of restoring normal spine function as early as possible to permit normal head shape development, as well as normal brain development, in order to prevent or reduce later issues such as learning difficulties and attention deficits. 


What is the short term effect of plagiocephaly or head asymmetry?  

The next year, in 2001, research was published which this time looked at the short term effects of head asymmetry. The objective of this study was to determine whether children with plagiocephaly, demonstrated cognitive and psychomotor delays when compared with a standardised population sample. The group with plagiocephaly were tested at al average age of 8 months, 0% of the subjects in the plagiocephaly group were accelerated, 67% were normal, 20% had mild delay and 13% had significant delay.  This study indicates that before any intervention, babies with plagiocephaly demonstrate delays in cognitive and psychomotor development by an average of 8 months of age. 

We can see from this research that occipital plagiocephaly is associated with cognitive and psychomotor developmental delays in 33% of babies by 8 months of age. This can persist, resulting in 39.7% of children with persistent occipital plagiocephaly, going on to experience learning difficulties and attention deficits when attending primary school. 


Does helmet therapy help plagiocephaly or head asymmetry?  

Helmet use has been demonstrated to improve the head shape of babies with plagiocephaly, and helmet therapy is being used up to 18 months of age with the best result obtained prior to 12 months of age. However the research of Miller and Clarion indicated that the use of helmets did not alter the long term issue with learning difficulties: about 40% of the helmet group later experienced learning difficulties which was the same percentage as the untreated group. Using helmets on their own will improve the head shape, but will not alter the associated problem of brain development in babies with plagiocephaly. Chiropractors understand that it is important to restore normal cervical spine function to permit normal brain development in babies with occipital plagiocephaly. 


How does correcting cervical spine function help brain development? 

Development and growth of our brain and nervous system is dependent on sensory input. The technical term for this is afforestation. We get our sensory input from our eyes, ears, taste, touch and proprioception. Proprioception is all the information and messages going to the brain from the joints, muscles and ligaments. Proprioception provides a massive and continuous barrage of messages into the brain via the spinal cord. 90% of the total sensory input to the brain comes from the spine and associated structures, especially the upper cervical spine which has the greatest density of nerve receptors in the spine. 

Sensory input stimulates the cells of the brain to form connections, or pathways, replicate and help develop the architecture of the brain. Sensory input is so important that without sufficient sensory input, our brain starts to make it up and we start to hallucinate. But an even more serious effect is that abnormal sensory input can result in failure of the brain to develop correctly, causing in extreme cases, mental retardation. 

Cervical spine dysfunction will produce altered neurological function. This means that cervical spine dysfunction will alter sensory input, and the resultant change in neurological function will affect brain development. Our job as Chiropractors is to detect joint dysfunction along with the effect this is having on the nervous system and the sensory input. By correcting the joint dysfunction and permitting normal sensory input, optimal brain development will be possible. Also by restoring normal cervical spine function, the baby will no longer have a positional preference resulting in improvement of the baby’s head shape. Clinically, the best results regarding improved head shape and normal proprioception are obtained with treatment and correction of any abnormal cervical spine function prior to six months of age. However, improvement can be obtained at any age. 


How is plagiocephaly managed? 

The first and most important aspect of correcting head asymmetry is to restore normal cervical spine function. This is best achieved by Chiropractors. Once normal cervical spine function has been restored, positional management where the baby’s head is turned to the non flat side while asleep, can then be effective. If the cervical spine issue is not resolved, then positional management is less effective. If there is involvement of the neck muscle (such as a sternocleidomastoid tumour), then stretching exercises will need to be part of the program of care. The stretching exercises will be provided by your Chiropractor. It is important to resolve any issue regarding muscle contracture as early as possible to minimise the possibility of later need for surgical correction of the muscle tissue. 

As a general rule, resolution of the head asymmetry will require a time period equal to the infant’s age, when normal cervical spine function has been restored. This means that a four month old infant who has been treated and now has normal cervical spine function, can expect significant resolution of head asymmetry after four months with positional management. It is important to monitor your infant’s neurological progress and status during the period of head shape correction to permit an optimal outcome.  


Leave a Reply