Electrophysiological signatures: Magnetoencephalographic studies of the neural correlates of language impairment in autism spectrum disorders

Abstract

While magnetoencephalography (MEG) is of increasing utility in the assessment of pediatric patients with seizure disorders, this indication reflects only a part of the clinical potential of the technology. Beyond epilepsy, a broad range of developmental psychiatric disorders require the combined offerings of spatial and temporal resolution, along with direct sensitivity to neural electrical activity, that are offered by MEG. This article reviews the application of MEG in the study of auditory processing as an aspect of language impairment in children. Potential application is elaborated in the clinical case of autism spectrum disorders, a devastating disorder with prevalence of 1 in 150, poorly served by alternative imaging modalities. MEG offers both spatial and temporal insights, tentatively described as "electrophysiological signatures". Results demonstrate the sensitivity of MEG for detection of abnormalities of auditory processing in ASD and their clinical correlates. These findings offer promise for the comprehensive assessment of developmental neuropsychiatric disorders such as autism, but also suggest avenues for the development of MEG technology to adequately meet the needs of such populations, as well as providing conduits to basic sciences including neurobiology and genetics.

A review of behavioural and electrophysiological studies on auditory processing and speech perception in autism spectrum disorders

“…Possibly, this superiority may be due to atypical brain lateralisation for auditory processing and speech perception in individuals with ASD. A number of auditory electrophysiological studies have found indications of either right hemisphere dominance or left hemisphere deficits in individuals with ASD (Bruneau et al, 1999;Gage, Siegel, Callen, & Roberts, 2003;Kasai et al, 2005;Oram Cardy et al, 2008;Roberts et al, 2008). Flagg, Oram Cardy, Roberts, and Roberts (2005), in particular, investigated ERF maturational patterns for lateralization in children with autism (with language impairment) and found a reversed maturational pattern of lateralization.…”

Fragile Spectral and Temporal Auditory Processing in Adolescents with Autism Spectrum Disorder and Early Language Delay

“…In this regard, a number of electrophysiological and neuroimaging studies reported right hemisphere dominance of auditory processing and speech perception in individuals with ASD, while controls showed left hemisphere dominance (e.g., Boddaert et al 2003;Bruneau et al 1999;Eyler et al 2012;Flagg et al 2005;Müller et al 1998Müller et al , 1999Redcay and Courchesne 2008;Roberts et al 2008; but see Whitehouse and Bishop 2008). Flagg et al (2005), in particular, observed a reversed maturational pattern of lateralization: Whereas controls matured from bilateral activation to left hemisphere dominance in the processing of speech sounds, children with autism matured towards right hemisphere dominance.…”

Improving the Prediction of Response to Therapy in Autism

“…54 In a recent pilot study, investigators in our research group used magnetoencephalography to examine brain responses to various tones in children with ASD com-pared to healthy controls (manuscript under preparation), and identified different signal processing in the two groups. Previous studies have found that certain magnetoencephalography signals are associated with auditory and language impairment in ASD, 55 and others have found that particular brain regions may be unable to generate high-frequency activity that may be necessary for connecting signals to various parts of the brain. 56 Similarly, other groups have identified psychophysiological measures, such as abnormal eye tracking and pupillary reactivity, which are associated with the fragile X syndrome.…”