Intellectual Profiles in the Autism Spectrum and Other Neurodevelopmental Disorders.

Mouga et al. (2016) compared WISC-III scores across kids with autism and other clinical groups. They matched the groups on overall IQ first, then looked for small, specific gaps.

The team pulled existing test files. They lined up the autism group with kids who had ADHD, language disorder, or intellectual disability.

Even with the same full-scale IQ, the autism group scored lower on verbal IQ, processing speed, and three subtests: Comprehension, Coding, and Symbol Search.

The gap shows up no matter how bright the child is. Processing speed was the clearest weak spot.

Mayes et al. (2008) saw the same pattern with the newer WISC-IV: high perceptual reasoning, low processing speed. The finding repeats across test versions.

McGonigle-Chalmers et al. (2013) give a twist. When they removed the clock, autism kids jumped up on the same WISC-III subtests. Timing, not thinking, may create the low scores.

Nader et al. (2016) and Wormald et al. (2019) both show WISC scores can sit far below other IQ tools. Their work tells us to double-check any low WISC number before writing goals.

If you see low processing speed or Comprehension scores on a WISC, pause. Ask: is this real weakness or test format? Try an untimed task or a nonverbal battery like Leiter-3 before you target "slow processing" in the plan. Share the profile with teachers so they do not mistake slow work for lack of understanding.