No evidence of early head circumference enlargements in children later diagnosed with autism in Israel.
Ilan Dinstein, Shlomi Haar, Shir Atsmon and 1 others
PMID 28344758WHAT IT FOUND
In children later diagnosed with autism, head circumference did not show early overgrowth compared with matched controls.
Controls had larger head circumference and weight at birth and 3 months, and head size did not relate to autism severity or verbal status.
Key findings
01Toddlers later diagnosed with autism did not show larger head circumference than matched controls during the first 24 months; controls had larger head circumference at birth and 3 months.
02Fitted growth curves showed no difference in head growth rate between autism and control toddlers.
03Head circumference was not meaningfully related to autism severity at diagnosis, including when nonverbal and verbal toddlers were examined separately.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
The study was retrospective and came from one healthcare service in southern Israel, so it may not apply to other populations. It excluded children with known genetic or chromosomal disorders, hydrocephalus, other developmental or neurological disorders, birth before 36 weeks, or birth weight below 2 kg, so it does not address syndromic forms of autism. Measurements came from routine wellness visits, and the number and timing of visits depended on parental compliance. The analyses were not corrected for multiple comparisons, so some reported differences may be chance findings. Head circumference is a coarse measure and does not directly show brain growth or gray and white matter changes.
Declared interests
Funded by the German-Israeli Foundation for Scientific Research and Development and the Israel Science Foundation. No author conflict-of-interest statements are provided in the supplied text.
The easy way to misread this
Do not read this as proof that early brain overgrowth never occurs in autism. The study used head circumference, not brain imaging, in non-syndromic children from one Israeli healthcare district, and it excluded known genetic disorders.