Diagnosing Autism by Brain Scans

A British study using brain scans obtained through magnetic resonance imaging (MRI) set out to identify a model in which autism was marked not by one or another of the differences previously examined by scientists, but by a combination of five specific traits in the size and shape of the brain. It used a relatively small sample of 20 autistic men, paired with 20 neurotypical men in a control group. A third group of 19 men with ADHD was used to determine that the model was correctly identifying autism spectrum disorder (ASD) specifically, and not brain differences in general.

"The accuracy of the scan in predicting autism was so high that the results were strongly significant, despite the small number of patients involved," said a Reuters news story, which stated the criteria used in the study were 90 percent effective at identifying the autistic test subjects. Study authors reflected that behaviour-based diagnosis is only about 80 percent accurate. The next step according to Declan Murphy, one of the researchers who conducted the study, is to see if the same set of criteria will also work for identifying children with autism.

Significance for autism diagnosis

Media reports have hailed the study as highly significant despite the small sample, and imply the new technique could be put to use in autism diagnosis very soon. Reactions from the scientific world tend to be more reserved. "[I]t will need many more studies before the technique used in this study can be used for diagnosis," cautioned Uta Frith, a cognitive psychologist known for her work in the field of autism.

It be important to determine if the diagnostic criteria work with children as accurately as with adults. As all the participants in the study were either diagnosed with either high functioning autism or Asperger's Syndrome, there is also the question of whether results will be as promising for identification of individuals who fall elsewhere on the autism spectrum.

Could brain scans replace conventional autism diagnosis?

At this point Murphy sees the scan as an additional diagnostic tool, and not a replacement. The short time involved in doing the test and the relatively low cost were emphasized but it is important to consider factors such as the potential need to sedate a very young child in order to perform the test, as well as the long wait for MRI testing in many hospitals.

Early autism screening and treatment

A very simple, non-invasive autism screening can already be performed by a pediatrician or family doctor in just minutes at the 18-month well baby check-up. While it is not officially a diagnostic tool, it does provide enough information to indicate a possibility of autism. The American Academy of Pediatrics now recommends therapeutic intervention immediately when autism is suspected, without waiting for a confirmed diagnosis. Best practice for autism is early intensive behavioural intervention, which often includes an element of play and social interaction. Therapy for autistic children is non-invasive, and poses no known risk to children who are later found not to be autistic.

Autism diagnosis only one step

As Carol Povey of the National Autistic Society points out, diagnosis by brain scan or by conventional methods is just the beginning. Autistic children require intensive therapy, support systems for themselves and family members, special education and professional services such as speech or occupational therapy. Many autistic children and adults go without these services, sometimes never getting even one session with a qualified professional. In addition to developing better diagnostic tools for autism, we need to work on supplying these needs throughout the entire life of the autistic individual.

Sources:

Christine Ecker et al, "Describing the brain in autism in five dimensions." The Journal of Neuroscience

Ben Hirschler, "Quick brain scan could screen for autism." Reuters