Auditory sustained potential as a biomarker of language functioning in children with autism and its implication in...

Most children with autism have language impairment, however, its neural mechanisms are not well understood. A potential biomarker associated with language in autism is a 40Hz Auditory Steady-State Response (ASSR) triggered by periodic click-trains which in electroencephalogram (EEG) evokes two types of responses - 40Hz steady-state gamma response (ASSR) and sustained potential (SP). Although these responses represent low-level auditory processing, they correspond to different stages of sound perception/analysis and are essential in processing of spectrally/temporally complex sounds. However, until now there were no studies focusing on the potentials of these responses in clinical trials.

The present open-label pilot study evaluated the effects of the probiotic beverage supplement Bio-K+ in children with autism (N = 19). Participants were assessed at three timepoints: T0 (baseline), T14 (14 weeks after intervention), and T22 (8 weeks after intervention, post-supplementation follow-up assessment), including EEG 40Hz ASSR and behavioral phenotyping.

First, at T0 we showed a reduction of SP amplitude in children with autism compared to controls, and this reduction was associated with lower speech/language/communication scores. Second, the amplitude of SP became significantly more negative during the probiotic supplementation period and, by T14, was no longer significantly different from the observed in TD controls. Finally, these changes in the amplitude of SP were associated with improvement in speech/language/communication scores.

This study showed that the SP as well as its change was related specifically to speech/language/communication but not to other behavioral measures and has a potential to be used in future clinical trials.