Children with autism show increased reaction time and unique brain wave patters during tasks that include novel distracters.

A review of: Estate Sokhadze, Joshua Baruth, Allan Tasman, Lonnie Sears, Grace Mathai, Ayman El-Baz, Manuel F. Casanova (2009). Event-related Potential Study of Novelty Processing Abnormalities in Autism Applied Psychophysiology and Biofeedback, 34 (1), 37-51 DOI: 10.1007/s10484-009-9074-5

In this study the authors conducted an Event-Related Potential (ERP) examination of children with autism while performing neurocognitive attention tests. ERP is similar to a traditional EEG (Electroencephalogram) except that the apparatus records brain electrical functioning specifically when very discrete events occur (such as when the person clicks on a key or sees a specific picture). This type of studies help the researchers examine brain electrical changes that occur in different regions of the brain when the child does certain tasks or are exposed to specific stimuli.

The study included 11 children and young adults with autism (10 males, 9 to 27 years of age) and 11 matched typically developing peers (9 males, 11 to 27 years of age). The participants completed an Odd-Ball task. In this task, the participants are asked to press a key when they see the target letter ( “X” ) on a computer screen. This target letter is presented 25% of the trials. For 50% of the trials a common distracter (the letter “O”) is presented instead. For the remaining 25%, a set of novel distracters are presented (different symbols). The researchers recorded the reaction time, accuracy, and brain electrical functioning during the task.

The results showed that participants with autism were slower to press on the key when the target X was presented than typically developing peers. However, the groups did not differ in accuracy of responding. That is, both groups were equally accurate in responding to the X target, but the group with autism showed a slower patter of responses. The group with autism also showed a different pattern of brain activation when confronted with the novel distracters. Their differences were observed in both hemispheres, but were stronger in the right frontal regions. The pattern of responses observed (longer latencies and higher amplitudes) suggest greater effort when processing novel stimuli. This finding is intriguing because the brain response patterns to the other stimuli (target X and the common distracter O) were identical between the groups. These results suggest that the group with autism had difficulty processing and disengaging from novel distracting stimuli.

At the end of the manuscript the authors raise one interesting issue. These results may contribute to the development of classification strategies that identify specific subgroups of children that may benefit from different treatment interventions. For example, the use of neurofeedback in developmental disorders has been growing considerably during the past decade. Neurofeeback is an extension of biofeedback. In biofeedback the person receives immediate feedback about their autonomic system (e.g., heart rate, blood pressure, etc) and is taught how to control these indices. In neurofeedback, the person receives real-time feedback on their brain functioning and is taught how to progressively modify their responses. However, the debate regarding the effectiveness of neurofeedback is ongoing as the research is limited and highly contradictory.

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