Delayed Walking with Autism and Intellectual Disability

Pediatrics published a large study on the relationship between delayed walking in children and the severity of intellectual disability in children with autism spectrum disorders (ASD) versus other non-ASD diagnoses.  The study sample included 1185 individuals (ASD, n = 903; non-ASD, n = 282) who received an evaluation at age 4 to 12 years that included an estimate of nonverbal IQ (NVIQ) and retrospectively reported age of walking from the Autism Diagnostic Interview–Revised. Delayed walking was defined as occurring at ≥16 months.

The results indicated the following:

1. children with ASD were less likely to exhibit delayed walking than those with non-ASD diagnoses
2. rates of delayed walking for ASD was 13%
3. rates of delayed walking for non-ASD was 19%
4. rates of delayed walking in those with NVIQ >85 was 31%
5. rates of delayed walking in children with NVIQ < 70 was 60%

Overall,  the difference between the children with ASD and those with non-ASD diagnosis was larger at lower levels of NVIQ.

The researchers concluded that lower IQ scores were associated with increased rates of late walking in both ASD and non-ASD groups but children with low IQ were more likely to show delayed walking in the absence of ASD.

Reference:  Somer L. Bishop, Audrey Thurm, Cristan Farmer, Catherine Lord. Autism Spectrum Disorder, Intellectual Disability, and Delayed Walking. Pediatrics. March 2016, VOLUME 137 / ISSUE 3.