Sensory Processing in Autism: A Review of Neurophysiologic Findings

Department of Neurology, University of California, San Francisco, California 94143, USA.
Pediatric Research (Impact Factor: 2.31). 02/2011; 69(5 Pt 2):48R-54R. DOI: 10.1203/PDR.0b013e3182130c54
Source: PubMed


Atypical sensory-based behaviors are a ubiquitous feature of autism spectrum disorders (ASDs). In this article, we review the neural underpinnings of sensory processing in autism by reviewing the literature on neurophysiological responses to auditory, tactile, and visual stimuli in autistic individuals. We review studies of unimodal sensory processing and multisensory integration that use a variety of neuroimaging techniques, including electroencephalography (EEG), magnetoencephalography (MEG), and functional MRI. We then explore the impact of covert and overt attention on sensory processing. With additional characterization, neurophysiologic profiles of sensory processing in ASD may serve as valuable biomarkers for diagnosis and monitoring of therapeutic interventions for autism and reveal potential strategies and target brain regions for therapeutic interventions.

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Available from: Leighton Hinkley, Jul 10, 2014
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    • "uch as autism spectrum disorders ( Brandwein et al . , 2015 ; Zhang et al . , 2014 ) . Although most sensors are located peripherally , the problem appears to lie centrally in the integra - tion of the sensory inputs , with these individuals incapable of perceiving auditory , visual , and tactile stimuli effectively ( Ben - Sasson et al . , 2009 ; Marco et al . , 2011 ) ."
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    ABSTRACT: Sensory inputs are integrated extensively before decision making, with altered multisensory integration being associated with disorders such as autism. We demonstrate that the two C. elegans AIB interneurons function as a biphasic switch, integrating antagonistic, tonic, and acute inputs from three distinct pairs of sensory neurons to modulate nociception. Off food, animals reverse away from a noxious stimulus. In contrast, on food or serotonin, AIB signaling is inhibited and, although animals initiate an aversive response more rapidly, they continue forward after the initial backward locomotion is complete. That is, animals continue to move forward and feed even when presented with a noxious repellant, with AIB inhibition decreasing the repellant concentration evoking a maximal response. These studies demonstrate that the AIBs serve as an integrating hub, receiving inputs from different sensory neurons to modulate locomotory decision making differentially, and highlight the utility of this model to analyze the complexities of multisensory integration. Dysfunctional sensory signaling and perception are associated with a number of disease states, including autism spectrum disorders, schizophrenia, and anxiety. We have used the C. elegans model to examine multisensory integration at the interneuron level to better understand the modulation of this complex, multicomponent process. C. elegans responds to a repulsive odorant by first backing up and then either continuing forward or turning and moving away from the odorant. This decision-making process is modulated extensively by the activity state of the two AIB interneurons, with the AIBs integrating an array of synergistic and antagonistic glutamatergic inputs, from sensory neurons responding directly to the odorant to others responding to a host of additional environmental variables to ultimately fine tune aversive behaviors. Copyright © 2015 the authors 0270-6474/15/3510331-12$15.00/0.
    The Journal of Neuroscience : The Official Journal of the Society for Neuroscience 07/2015; 35(28):10331-42. DOI:10.1523/JNEUROSCI.0225-15.2015 · 6.34 Impact Factor
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    • "This finding suggests that early impairments in synchrony detection could negatively impact language development in populations with disabilities. Difficulty with intersensory processing is well established in autism (for reviews, see [23] [24]); however, the nature of the deficit, particularly the impact on language development , is far less studied. Bahrick and Todd [25] have described ways in which early impairments in detection of intersensory redundancy, including detection of temporal synchrony, may trigger a cascade of disordered developments that yield symptoms of autism. "
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    ABSTRACT: Temporally synchronous audio-visual stimuli serve to recruit attention and enhance learning, including language learning in infants. Although few studies have examined this effect on children with autism, it appears that the ability to detect temporal synchrony between auditory and visual stimuli may be impaired, particularly given social-linguistic stimuli delivered via oral movement and spoken language pairings. However, children with autism can detect audio-visual synchrony given nonsocial stimuli (objects dropping and their corresponding sounds). We tested whether preschool children with autism could detect audio-visual synchrony given video recordings of linguistic stimuli paired with movement of related toys in the absence of faces. As a group, children with autism demonstrated the ability to detect audio-visual synchrony. Further, the amount of time they attended to the synchronous condition was positively correlated with receptive language. Findings suggest that object manipulations may enhance multisensory processing in linguistic contexts. Moreover, associations between synchrony detection and language development suggest that better processing of multisensory stimuli may guide and direct attention to communicative events thus enhancing linguistic development.
    12/2014; 2014:Article ID 678346. DOI:10.1155/2014/678346
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    • "For example, children with autism often have enhanced pitch discrimination, but are less able to discriminate between speech sounds in background noise (O’Connor, 2012). While studies documenting neural responses to simple stimuli in individuals with autism have conflicting results, neural responses to spectrotemporally complex stimuli in individuals with autism are consistently impaired (Čeponienė et al., 2003; Marco et al., 2011; O’Connor, 2012). "
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    ABSTRACT: Children with autism often have language impairments and degraded cortical responses to speech. Extensive behavioral interventions can improve language outcomes and cortical responses. Prenatal exposure to the antiepileptic drug valproic acid (VPA) increases the risk for autism and language impairment. Prenatal exposure to VPA also causes weaker and delayed auditory cortex responses in rats. In this study, we document speech sound discrimination ability in VPA exposed rats and document the effect of extensive speech training on auditory cortex responses. VPA exposed rats were significantly impaired at consonant, but not vowel, discrimination. Extensive speech training resulted in both stronger and faster anterior auditory field (AAF) responses compared to untrained VPA exposed rats, and restored responses to control levels. This neural response improvement generalized to non-trained sounds. The rodent VPA model of autism may be used to improve the understanding of speech processing in autism and contribute to improving language outcomes.
    08/2014; 8:137. DOI:10.3389/fnsys.2014.00137
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