Children with Asperger's Syndrome have different electroencephalography (EEG) patterns to children with autism, reveals a study in the open access journal BMC Medicine With distinct neurophysiology, the study pours fresh fuel on the on-going debate about how Asperger's should be classified.

People with Asperger's syndrome experience social difficulties, and display restricted and repetitive behavioural patterns and interests. Until recently, the condition was classified as a disorder in its own right, distinct from the Autism Spectrum Disorder (ASD), which manifests some overlapping symptoms. But the most recent edition of the mental health manual, the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), published earlier this year, reversed the decision, lumping Asperger's in with ASD.

Frank H. Duffy and colleagues at the Departments of Neurology and Psychaitry of Boston Children's Hospital studied electrical recordings from the scalps of children with Asperger's and children with ASD. They looked at EEG-derived measures of brain connectivity, and found that, although the disorders were closely related, there were clear neurophysiological differences between the groups.

The results show that Asperger's and ASD can be discriminated on the basis of electrical activity in the brain. Asperger's is a normally distributed entity that fits within the higher functioning end of the ASD. Just as dyslexia is now recognized as the low end of the reading ability distribution curve, so, the authors suggest, Asperger's syndrome could be usefully defined as a distinct entity within the higher functioning end of the autism distribution curve. However, the authors caution that, with study numbers low, the results need replicating in larger numbers before any firm conclusions can be drawn.

In the meantime, the stakes are high. Merging the diagnosis of Asperger's into ASD, effectively removes the disorder as condition in its own right. Families and advocates are concerned that some people could lose their diagnosis, leading to repercussions at clinical, educational, emotional and financial levels.