Hemispheric differences in language processing in autism spectrum disorders: A meta‐analysis of neuroimaging studies

Abstract

Language impairments, a hallmark feature of autism spectrum disorders (ASD), have been related to neuroanatomical and functional abnormalities. Abnormal lateralization of the functional language network, increased reliance on visual processing areas, and increased posterior brain activation have all been reported in ASD and proposed as explanatory models of language difficulties. Nevertheless, inconsistent findings across studies have prevented a comprehensive characterization of the functional language network in ASD. The aim of this study was to quantify common and consistent patterns of brain activation during language processing in ASD and typically developing control (TD) participants using a meta-analytic approach. Activation likelihood estimation (ALE) meta-analysis was used to examine 22 previously published functional Magnetic Resonance Imaging (fMRI)/positron emission tomography studies of language processing (ASD: N = 328; TD: N = 324). Tasks included in this study addressed semantic processing, sentence comprehension, processing figurative language, and speech production. Within-group analysis showed largely overlapping patterns of language-related activation in ASD and TD groups. However, the ASD participants, relative to TD participants, showed: (1) more right hemisphere activity in core language areas (i.e., superior temporal gyrus and inferior frontal gyrus), particularly in tasks where they had poorer performance accuracy; (2) bilateral MTG hypo-activation across many different paradigms; and (3) increased activation of the left lingual gyrus in tasks where they had intact performance. These findings show that the hypotheses reviewed here address the neural and cognitive aspects of language difficulties in ASD across all tasks only in a limited way. Instead, our findings suggest the nuances of language and brain in ASD in terms of its context-dependency. Autism Res 2016, 9: 1046-1057. © 2016 International Society for Autism Research, Wiley Periodicals, Inc.

Emotion processing in early blind and sighted individuals.

“…In fact, recent evidence suggests that the often observed right-hemispheric dominance in processing facial emotional expressions may indeed depend on the right-lateralized network for face processing (Worley & Boles, 2016). In this regard, it is interesting that individuals who show developmental delays associated with autism spectrum disorder (and whose prevalence is particularly high in blind children, Jure, Pogonza, & Rapin, 2016) also present abnormal hemispheric lateralization in different tasks (Floris et al, 2016; Herringshaw, Ammons, DeRamus, & Kana, 2016; but see Baker, Montgomery, & Abramson, 2010), including atypical hemispheric specialization for faces (Keehn, Vogel-Farley, Tager-Flusberg, & Nelson, 2015). …”

Aberrant Development of Speech Processing in Young Children with Autism: New Insights from Neuroimaging Biomarkers

“…The study of the connectivity profile using a resting-state fMRI protocol during infancy and toddlerhood is now needed to further our understanding regarding how the functional connectivity between reward pathways and voice- and speech-related brain areas develops. Several neuroimaging studies performed in high-functioning older children and adults with ASD point to the presence of impairments in the neural basis of language processing in general (e.g., Gaffrey et al, 2007; Knaus et al, 2008; Herringshaw et al, 2016 for recent review). These experiments often including an overt task have revealed the existence of abnormal frontal and/or temporal responses during language processing tasks compared to TD individuals and reversed or reduced laterality within fronto-temporal language regions (e.g., Boddaert et al, 2003; Flagg et al, 2005; Kleinhans et al, 2008; Knaus et al, 2010; Lindell and Hudry, 2013; Herringshaw et al, 2016).…”

The language network in autism: Atypical functional connectivity with default mode and visual regions

“…Functional imaging studies have revealed further anomalies of language processing in ASDs, including recruitment of visual regions during language tasks [Gaffrey et al, ; Kana, Keller, Cherkassky, Minshew, & Just, ; Knaus, Silver, Lindgren, Hadjikhani, & Tager‐Flusberg, ; Pang et al, ], increased activation in homologous language regions of the right hemisphere [Anderson et al, ; Eyler, Pierce, & Courchesne, ; Groen et al, ; Herringshaw, Ammons, DeRamus, & Kana, ; Kleinhans, Müller, Cohen, & Courchesne, ; Knaus et al, ; Müller et al, ; Nielsen et al, ; Williams, Goldstein, & Minshew, ], and reduced connectivity of left inferior frontal cortex and right cerebellum with other language regions [Verly et al, ].…”