Stereotyped motor behaviors associated with autism in high-risk infants: a pilot videotape analysis of a sibling sample.

Researchers watched home videos of baby siblings. Some babies later got an autism diagnosis. Others did not.

The team counted how often each baby flapped arms or put hands to ears at 12 and 18 months.

Babies who later had autism waved their arms more at both ages. They also pressed hands to ears more at 18 months.

Typical babies did these things too, just less often. The actions overlapped, so no single move meant autism.

Ozonoff et al. (2008) saw the same age-12 warning sign, but with spinning toys instead of arm moves. Together the papers say, "Watch for any odd repeated motion at one year."

Melo et al. (2023) looked at older autistic kids and found over half still had body stereotypies. The new work shows the seeds of those same motions appear before the first birthday.

Harrop (2015) notes most parent programs ignore these early quirks. Alvin’s pilot gives coaches a reason to target arm flaps and ear pressing in baby sessions.

You can spot possible autism risk during ordinary play. Note extra arm waving at one year and hands-to-ears at one-and-a-half. Share these clips with families and doctors. Early cues mean earlier support, even before words emerge.