Brainstem auditory evoked potential study in children with autistic disorder.

Doctors placed small earphones on the kids. Ten had infantile autism, ten had mental retardation, ten were typical.

Each child heard rapid clicks. A computer measured how fast the sound traveled up the brainstem.

The test is called BAEP. It needs no talking or pointing, so even non-verbal children can do it.

Autistic children needed more time for the signal to move through the brainstem. The delay averaged 0.2 milliseconds.

Longer delay matched stronger autistic traits. Kids with the biggest lag also had the most social and language issues.

Burgess et al. (1986) saw the same "brain looks younger" pattern with EEG. Slow waves were more common in autistic kids.

Wallander et al. (1983) also found slower cortical timing. Together, three studies point to a wide neural maturation lag.

Lortie et al. (2017) seems to disagree. They found normal early sound detection in ASD. The key difference is timing. BAEP captures the first 10 milliseconds inside the brainstem. MMN happens later, after 100 milliseconds. Early wires are slow, later filters still work.

If a child ignores voices, check hearing first. A simple 15-minute BAEP can rule out brainstem delay. When delay shows up, use clear, slower speech and visual cues to give the brain extra time. Share the result with speech and audiology teams so everyone targets the same sensory bottleneck.