Movement research – ASD #5

I’ve had several parents come into the clinic over the past weeks and ask about their baby’s ability to do a “pull-to-sit” task. Of course they’ve heard of the study that says children delayed in their pull-to-sit (PTS) ability may have autism. The original study was published quite a few years ago but the topic continues to resonate. Let’s recap with the 2023 study by Bradshaw et al. This study looked at 100 infants in elevated-likelihood for ASD, low familial risk for ASD and typically developing categories. The study found a significantly greater proportion of infants with head lag on PTS at 4 months and older and beyond in elevated-likelihood infants as well as those later diagnosed with ASD.

But here’s what I find most interesting about this new study. The authors assessed shoulder muscle tone, muscle activation and head lag during PTS as well as head righting in supported sitting. Infants with elevated-likelihood of ASD and those later diagnosed with ASD demonstrated sufficient PTS skills when evaluating shoulder muscle tone, muscle activation and head righting in supported sitting, but they still demonstrated a head lag. This suggests that there may be an alternative mechanism for the head lag; anticipatory postural control, adaptive motor control or action-coordination challenges are all suggested as possibilities.

The study also demonstrated a correlation between prolonged difficulty with PTS and social communication skills. PTS trajectories predicted the use of nonverbal social behaviours to communicate at 24 months. The authors note that as social-communication skills involve gestures and gaze shifts, they are linked to motor control of the trunk, head, neck, arms and hands.

There are complexities in this study and I do encourage you to read it for yourself. It is important information for clinicians but it also requires us to be cautious – we know that many children with sensory and motor challenges display ongoing difficulties with PTS. Hopefully future research will provide more clarity. At present, when parents ask about their baby’s PTS, I broaden the conversation to include familial history of ASD as well as gathering more information regarding the 12 components of postural control.


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