June 27, 2012

EEG Helping To Diagnose Autism

Lee Rannals for redOrbit.com

Scientists are using a brain trace to help diagnose autism, which has been notoriously hard for doctors to identify in patients.

Researchers at Boston Children's Hospital and Harvard Medical School said EEG traces could help offer a diagnostic test for autism in children.

Autism is characterized by impaired communication, such as language and social skills. Although MRI studies have reported differing results, EEG measurements have been more consistent.

Researchers wrote in the journal BMC Medicine that EEG can distinguish between children with autism, and neurotypical controls.

During the latest study, 33 specific EEG patterns were found that appeared to be linked to autism. These patterns consistently spotted autism in children between the ages of 2 to 12 years old.

The team repeated their analysis 10 times, splitting up their study group in different ways. About 90 percent of the time, the EEG patterns could correctly detect the children diagnosed with autism.

They wrote that autistic children in the study showed a reduction in short range connectivity, indicating poor function of local brain networks, especially in the left hemisphere regions responsible for language.

The children had increased connectivity between regions that were further apart, indicating a compensatory mechanism.

They compared EEG measurements of almost 1,000 children with and without autism. Data was collected using 24 electrodes on the scalps of awake and alert subjects. The results were adjusted for events known to confound EEG results, like blinking, head movements or drowsiness.

"EEG coherence is used to assess functional connectivity within the brain," Boston Children's Hospital researchers Dr. Frank Duffy and Dr. Heidelise Als wrote in the journal. "Across all the age groups we tested, a set of 40 coherence measurements reliably and consistently distinguished between children with ASD and their controls."

The results showed widespread differences in brain connectivity, according to the researchers. They said they found that specifically short distance coherence was reduced in children with autism, especially in the left frontal regions associated with language.

The results may help in reliably diagnosing autistic children, as well as providing early detection in infants.

The team now plan to repeat their study in children with Asperger's syndrome, which is a particular subset of autism.  People with Asperger's have higher-than-average intelligence and struggle less with speech than people with other types of autism.

Duffy said the work could help determine whether or not Asperger's could be thought of as an entirely separate condition.

"We welcome any research that may help us to understand autism better and improve diagnosis times for those with the condition," Caroline Hattersley of The National Autistic Society said in a statement. "In a recent survey we commissioned, 50% of people with autism and their families said it was difficult to get a diagnosis and 55% said the process took too long."