No Significant Brain Abnormalities Found in Autism Spectrum Disorders

the Neurology Advisor take:

Little is understood about the pathology of autism and related disorders, and a new MRI study, the largest to date, provided little more evidence as to the differences in brain anatomy between a person with autism and a person who is typically developed.

There is longstanding controversy in the medical community regarding the presence of certain brain abnormalities in people with autism spectrum disorders. Previously reported abnormalities include larger intra-cranial gray matter, white matter and amygdala volumes or smaller cerebeller, corpus callosum and hippocampus volumes, according to Ilan Dinstein, MD, of Ben-Gurian University of the Negev in Israel, who was lead researcher of the study.

Dinstein and colleagues from Carnegie Mellon University used the Autism Brain Imaging Data Exchange database to compare MRI scans of approximately 1,000 people with autism ages 6 to 65 to a control group. Although the MRI analysis of people with autism spectrum disorders revealed larger ventricular volumes, smaller corpus callosum volume and increased thickness in several cortical areas, the scans did not substantiate any of the previous anatomical abnormalities that have been reported. 

"The most striking finding here was that anatomical differences within both the control group and the autistic group was immense and greatly overshadowed minute differences between the two groups," Dinstein told Medical News Today.

A multivariate classification analyses showed modest decoding accuracies of individuals’ group identity, which suggests that the anatomical differences observed are of little diagnostic use. The researchers also noted that although there may be abnormalities present in certain groups of people with autism spectrum disorders, the findings of the MRI study show that the previously reported abnormalities have little scientific or clinical significance for gaining a better understanding of the neuropathology of autism spectrum disorders.