What’s the News: A number of recent studies have suggested that brain scans could be used to diagnose autism. Virginia Hughes investigated these claims in a report for the Simons Foundation Autism Research Initiative. While some researchers feel these tests could soon be ready for the clinic, she found, others feel that relying on the scans for diagnosis is at least premature, and perhaps entirely misguided. Some important points in her report:

How the Would-Be Autism Tests Work:

The studies have focused on a variety of possible indicators of autism and used several types of scans: measuring activation of brain regions as people do or experience particular things; examining neural anatomy; tracing connectivity between parts of the brain; and analyzing the electrical activity produced by neurons firing.
All the scans, however, have one central goal: picking out reliable, predictive differences between the brains of children with autism and unaffected children.

The Shortcomings:

For the scans to be useful in diagnosis, they have to be able to distinguish children with autism not only from healthy children but from children with other conditions who have similar symptoms, such as trouble with language ...