The presence or absence of certain behaviors associated with infantile autism in severely retarded autistic and nonautistic retarded children and very young normal children.

The team watched kids and ticked boxes on a behavior checklist. They looked at three groups: very delayed autistic children, very delayed non-autistic children, and typical toddlers.

The goal was simple. Find which behaviors show up mostly in the autistic group. Those behaviors could then act as red flags during future evaluations.

A short pattern of behaviors did the trick. Autistic kids with severe delays showed these behaviors far more often than non-autistic kids with the same low IQ.

Interestingly, the gap was smaller between the two delayed groups than between either delayed group and the typical toddlers. The pattern points to autism, not just slow development.

Repp et al. (1992) repeated the same idea with a different checklist called the BSE. Their eight-item version also split autistic from non-autistic delayed kids, giving you a second quick screen to try.

Dammeyer (2014) sounds like a contradiction. That study found high autism scores in deaf-blind children, but blamed sensory loss, not autism. The difference is context: Green et al. (1987) tested kids whose main issue was intellectual disability, while Jesper’s children lacked both sight and sound. When senses are missing, checklist scores can mislead.

Dougherty et al. (1994) extended the logic further. They used CARS and RLRS to separate autistic children from psychotic children, showing the same "find the unique pattern" approach works across several diagnoses.

If you assess kids with severe delays, you can’t trust IQ alone. Run a brief autism behavior checklist. Look for the specific pattern—social withdrawal, odd toy use, and repetitive acts. When those items cluster, think autism first, not just global delay. Add the free BSE items from Repp et al. (1992) if you want a second opinion. And always ask about sensory status; deaf-blindness can fake autism signs, as Dammeyer (2014) warns.