Absence of M100 source asymmetry in autism associated with language functioning

Department of Radiology, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Neuroreport (Impact Factor: 1.52). 06/2009; 20(11):1037-41. DOI: 10.1097/WNR.0b013e32832e0ca7
Source: PubMed


Various clinical populations display atypical volume asymmetry of language structures and also the auditory M100 source. Although such atypical volume asymmetries have also been observed in autism, M100 source asymmetries have not yet been investigated. We examined M100 asymmetry in autism and its relationship with language functioning. Evoked neural activity to a 1 kHz tone was recorded using whole-cortex 151-channel magnetoencephalography in three groups of individuals. A single-dipole model identified the M100 generator in auditory cortex in each hemisphere. Healthy adults and control children displayed the expected right-sided M100 anteriority, whereas children with autism showed no such asymmetry. An association was found between language functioning and the degree of asymmetry across the two groups of children, suggesting a possible relationship between functional-structural asymmetry and language ability.

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    • "The STG which is a key structure in language function may be particularly susceptible to developmental perturbations as the development of language is relatively recent and language areas may be only weakly canalized [49]. Schmidt and colleagues demonstrated an association between language functioning and M100 source asymmetry in children, suggesting a possible relationship between functional/ structural asymmetry of the STG and language ability [50]. Crow offered an account of schizophrenia is linked to disturbances in language function, especially involving the temporal lobe [51]. "
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    ABSTRACT: Whether schizophrenia and bipolar disorder are the clinical outcomes of discrete or shared causative processes is much debated in psychiatry. Several studies have demonstrated anomalous structural and functional superior temporal gyrus (STG) symmetries in schizophrenia. We examined bipolar patients to determine if they also have altered STG asymmetry. Whole-head magnetoencephalography (MEG) recordings of auditory evoked fields were obtained for 20 subjects with schizophrenia, 20 with bipolar disorder, and 20 control subjects. Neural generators of the M100 auditory response were modeled using a single equivalent current dipole for each hemisphere. The source location of the M100 response was used as a measure of functional STG asymmetry. Control subjects showed the typical M100 asymmetrical pattern with more anterior sources in the right STG. In contrast, both schizophrenia and bipolar disorder patients displayed a symmetrical M100 source pattern. There was no significant difference in the M100 latency and strength in bilateral hemispheres within three groups. Our results indicate that disturbed asymmetry of temporal lobe function may reflect a common deviance present in schizophrenia and bipolar disorder, suggesting the two disorders might share etiological and pathophysiological factors.
    PLoS ONE 12/2013; 8(12):e82682. DOI:10.1371/journal.pone.0082682 · 3.23 Impact Factor
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    • "Although a few studies have successfully acquired EEG/ ERPs from nonverbal children with ASD (Dawson et al., 2002; Russo, Zecker, Trommer, Chen, & Kraus, 2009; Schmidt, Rey, Oram Cardy, & Roberts, 2009), there has been little documentation of the techniques involved in the successful net desensitization/application process that is paramount to collection of analyzable ERP data. Dawson et al. (2002) described a net desensitization/application technique used with young children with ASD, other developmental delays, and a control group. "
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    ABSTRACT: This study examined the effectiveness of sensory desensitization training for 12 nonverbal children with autism to facilitate participation in an electrophysiological study assessing linguistic processing. Sensory desensitization was achieved for 10 of the 12 children and thus allowed collection of usable data in a passive linguistic paradigm. Application of such desensitization methods may be useful as a precursor to other assessment protocols for individuals who are difficult to test.
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    • "With regard to P50m, the present study is the first to show the P50m source position in young children with ASD and to demonstrate that both TD and ASD children similarly displayed right-sided P50m anteriority. With regard to N100m, a previous study demonstrated right-sided N100m anteriority in 8- to 15-year-old TD children, whereas children with ASD did not show asymmetry [43]. However, we did not examine the N100m component in this study because of a lower GOF in the ECD estimation in 2- to 5-year-old children [31]. "
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    ABSTRACT: Magnetoencephalography (MEG) is used to measure the auditory evoked magnetic field (AEF), which reflects language-related performance. In young children, however, the simultaneous quantification of the bilateral auditory-evoked response during binaural hearing is difficult using conventional adult-sized MEG systems. Recently, a child-customised MEG device has facilitated the acquisition of bi-hemispheric recordings, even in young children. Using the child-customised MEG device, we previously reported that language-related performance was reflected in the strength of the early component (P50m) of the auditory evoked magnetic field (AEF) in typically developing (TD) young children (2 to 5 years old) [Eur J Neurosci 2012, 35:644--650]. The aim of this study was to investigate how this neurophysiological index in each hemisphere is correlated with language performance in autism spectrum disorder (ASD) and TD children. We used magnetoencephalography (MEG) to measure the auditory evoked magnetic field (AEF), which reflects language-related performance. We investigated the P50m that is evoked by voice stimuli (/ne/) bilaterally in 33 young children (3 to 7 years old) with ASD and in 30 young children who were typically developing (TD). The children were matched according to their age (in months) and gender. Most of the children with ASD were high-functioning subjects. The results showed that the children with ASD exhibited significantly less leftward lateralisation in their P50m intensity compared with the TD children. Furthermore, the results of a multiple regression analysis indicated that a shorter P50m latency in both hemispheres was specifically correlated with higher language-related performance in the TD children, whereas this latency was not correlated with non-verbal cognitive performance or chronological age. The children with ASD did not show any correlation between P50m latency and language-related performance; instead, increasing chronological age was a significant predictor of shorter P50m latency in the right hemisphere. Using a child-customised MEG device, we studied the P50m component that was evoked through binaural human voice stimuli in young ASD and TD children to examine differences in auditory cortex function that are associated with language development. Our results suggest that there is atypical brain function in the auditory cortex in young children with ASD, regardless of language development.
    Molecular Autism 10/2013; 4(1):38. DOI:10.1186/2040-2392-4-38 · 5.41 Impact Factor
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