Microcephaly and macrocephaly in autism.
Expect big heads in one-sixth of your autistic clients and small heads in another sixth, with the latter group needing medical screening.
01Research in Context
What this study did
Doctors pulled the growth charts of 126 autistic kids seen at their hospital.
They counted how many had heads larger or smaller than normal for their age.
What they found
One in six kids had big heads. Another one in six had small heads.
The small-head group often had other medical problems like seizures or genetic syndromes.
How this fits with other research
Cederlund et al. (2014) looked at preschoolers in the community and found only 3% had big heads. The difference is age and setting: the 1999 study mixed older clinic patients, while the 2014 study focused on three-year-olds in regular preschools.
Albores-Gallo et al. (2017) and Amaral et al. (2017) both saw the same one-in-five big-head rate in clinic kids, showing the pattern holds across countries.
Flor et al. (2017) tracked kids with small heads and confirmed they have more medical issues and lower test scores, so a small head is a red flag for deeper work-up.
Why it matters
Grab a tape measure. Plot head circumference at intake. A big head is common and usually harmless, but a small head signals possible seizures, genetic syndromes, or GI problems. Flag these kids for medical follow-up and adjust skill targets if you see slower learning.
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02At a glance
03Original abstract
Data from a series of 126 autistic children ages 2-16 years and referred to an Autism Diagnosis Unit in South-West France were examined. Macrocephaly (head circumference > 97th centile) was observed in 16.7% of the sample, a significantly higher proportion than that expected. Macrocephaly was more frequent among older subjects but was otherwise not associated with gender, developmental level, the presence of epilepsy or of medical disorders, or severity of autistic symptomatology. Microcephaly (head circumference < 3rd centile) was also significantly raised and found in 15.1% of the sample. Microcephaly was significantly associated with the presence of medical disorders. Results support those from recent studies suggesting a raised rate of macrocephaly in autism which, pooling published data, can be estimated to be 20%. It is argued that the raised incidence of microcephaly among low-functioning autistic subjects with medical disorders might have contributed to delay the recognition of an increased head circumference among a minority of subjects with idiopathic autism.
Journal of autism and developmental disorders, 1999 · doi:10.1023/a:1023036509476