RESEARCH

Early screening for autism at 18 months

Carrie Allison, Simon Baron-Cohen, Liliana Ruta, Carol Brayne, Tony Charman, Greg Pasco, Fiona Matthews, Emma Robson, Georgina Woods and Jillian Sullivan.

The ARC pioneered early screening for autism at 18 months of age, using the CHAT (Checklist for Autism in Toddlers). This focused particularly on the absence of key behaviours (pretend play and joint attention) at 18 months of age as early indicators of a later diagnosis of autism. Whilst failure on the CHAT was found to be strongly predictive of later autism, the CHAT missed many cases of later autism spectrum conditions, particularly Asperger Syndrome, reflecting the fact that the CHAT was developed in the early 1990s when Asperger Syndrome was less well known.

Our current work has revised the CHAT to make it quantitative (the Q-CHAT) in an effort to improve the sensitivity of the instrument. This has involved screening a large population of toddlers age 18-24 months old using the Q-CHAT, and then following them up at age 4 years old to identify if the Q-CHAT accurately predicts an ASC diagnosis in the school years. 

We are also investigating if head circumference is a risk factor for later autistic traits and/or ASC.