Development of the posterior basic rhythm in children with autism.

OBJECTIVE

Early detection of autism is critical for effective intervention, but currently, no simple screening tests are available. Furthermore, little is known about the development of brain dynamics in young children. We examine the early neurophysiological manifestations of autism by retrospectively analyzing EEG. In particular, we focus on maturation of the posterior basic rhythm (PBR), which is one of the most characteristic features of the normal EEG, and comprises a discrete functional state.

METHODS

Subjects with a diagnosis of autism (n=74), as well as normal (n=134) and epileptic (n=108) controls, were extracted retrospectively from our digital EEG database. Segments with clear PBR were extracted, and standard signal analysis methods were used to calculate peak PBR frequency, power, and coherence.

RESULTS

In our cohort, a subset of autistic children show accelerated development of the PBR, with early maturation especially in the 2- to 4-year old range. The overall coherence of PBR-specific activity is also lower in autistic children in our cohort.

CONCLUSIONS

These findings provide evidence that autism is associated with accelerated development of the PBR.

SIGNIFICANCE

These findings generate a clinical hypothesis for future prospective studies on the efficacy of these simple measures as a diagnostic or screening tool.