Sensory Impairments and Autism: A Re-Examination of Causal Modelling

Differential Altered Auditory Event-Related Potential Responses in Young Boys on the Autism Spectrum With and Without Disproportionate Megalencephaly

Autism spectrum disorder (ASD), characterized by impairments in social communication and repetitive behaviors, often includes altered responses to sensory inputs as part of its phenotype. The neurobiological basis for altered sensory processing is not well understood. The UC Davis Medical Investigation of Neurodevelopmental Disorders Institute Autism Phenome Project is a longitudinal, multidisciplinary study of young children with ASD and age-matched typically developing (TD) controls. Previous analyses of the magnetic resonance imaging data from this cohort have shown that ∼15% of boys with ASD have disproportionate megalencephaly (DM) or brain size to height ratio, that is 1.5 standard deviations above the TD mean. Here, we investigated electrophysiological responses to auditory stimuli of increasing intensity (50-80 dB) in young toddlers (27-48 months old). Analyses included data from 36 age-matched boys, of which 24 were diagnosed with ASD (12 with and 12 without DM; ASD-DM and ASD-N) and 12 TD controls. We found that the two ASD subgroups differed in their electrophysiological response patterns to sounds of increasing intensity. At early latencies (55-115 ms), ASD-N does not show a loudness-dependent response like TD and ASD-DM, but tends to group intensities by soft vs. loud sounds, suggesting differences in sensory sensitivity in this group. At later latencies (145-195 ms), only the ASD-DM group shows significantly higher amplitudes for loud sounds. Because no similar effects were found in ASD-N and TD groups, this may be related to their altered neuroanatomy. These results contribute to the effort to delineate ASD subgroups and further characterize physiological responses associated with observable phenotypes. Autism Res 2019, 12: 1236-1250. © 2019 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: Approximately 15% of boys with ASD have much bigger brains when compared to individuals with typical development. By recording brain waves (electroencephalography) we compared how autistic children, with or without big brains, react to sounds compared to typically developing controls. We found that brain responses in the big-brained group are different from the two other groups, suggesting that they represent a specific autism subgroup.

'Visual clutter' in the classroom: voices of students with Autism Spectrum Disorder

OBJECTIVES

To date, there has been little qualitative research exploring how students interpret visual sensory input in the classroom. Research has found that seeking student voice has the capacity to act as a change agent for Educational Quality of Life (EQOL), in several aspects of educational decision-making. In light of this knowledge, this study endeavored to fill this gap in the educational research literature. In this research, we take a qualitative, deductive approach to exploring students' interpretations of 'visual clutter' in the classroom, to seek to improve EQOL.

METHODS

Through Arts-informed methodology, this study sought students' interpretations of 'visual clutter' in the classroom. The study was conducted in three stages using photo elicitation, draw and talk, and semi-structured interviews.

RESULTS

In seeking three students' voices regarding their personal interpretations of 'visual clutter' in classrooms, light was shed on four themes: color palette, feature congestion, affordances, and spatial size, which were each shown to elicit negative emotional responses from the students. We analyzed the drawings of one child in depth as an exemplar for the qualitative methodology used.

CONCLUSION

Student voice is central to educational quality of life. In seeking student voice, students are given the opportunity to convey the scope of their adaptive responses to incoming visual input, thus providing personal context to support measures. In doing so, student voice is given meaning in another facet of educational decision-making. This can include implications for classroom design.

What Happened to Paul? Manifestation of Abnormal Pain Response for Individuals With Autism Spectrum Disorder

During the progression of a pilot nutrition intervention designed to teach cooking skills to young adults with autism spectrum disorder (ASD), one participant-Paul-fell in the parking lot. Prior to the accident, Paul had been making significant gains in the program and had communicated in a number of ways his enthusiasm. After his accident, which resulted in broken and dislocated bones in his ankle, his demeanor was dramatically altered, program gains were lost, and staff noted the appearance of many new challenging behaviors. This article analyzes Paul's behavior in reference to the pain response in autism. For some time, it was believed that many individuals with ASD did not experience pain based on anecdotal reports of how individuals responded to injury with seeming indifference. This view has given way of late to a more nuanced understanding of how atypical sensory processing and stimulus over-selectivity spill over into pain pathways and pain amplification mechanisms. The consequence is not a reduction in pain sensation, but a different expression of pain, determined by that individual's particular communicative, cognitive, or physiological challenges. From this perspective, many of the disruptive and harmful behaviors that emerged after Paul's accident can be seen as a delayed response to the incident. This article concludes by arguing that professionals across all domains of health care need to begin to see behavior as communicative for those with ASD. This is particularly true of changes in behavior, which can be significant indicators of health care problems rather than something to be dismissed as another manifestation of the condition.

Development of the anxiety scale for children with autism spectrum disorder (ASC-ASD)

Many children with autism spectrum disorder (ASD) experience high levels of anxiety. A widely used measure for typically developing children is the Revised Child Anxiety and Depression Scale (RCADS). However, such anxiety measures may require adaptation to accommodate characteristics of those with ASD. An adapted version of the RCADS was created based on empirical evidence of anxiety phenomenology in ASD, which included additional items related to sensory anxiety, intolerance of uncertainty, and phobias. Content validity was refined during focus groups with parents. Polychoric factor analysis was undertaken on data from 170 children with ASD, aged 8-16, and their parents. This process resulted in the creation of a new 24 item scale (self and parent report) each with four subscales: Performance Anxiety, Uncertainty, Anxious Arousal, and Separation Anxiety, with evidence of good reliability and validity. The freely available Anxiety Scale for Children - ASD, Parent and Child versions (ASC-ASD) has promising psychometric properties including good internal consistency, validity, and 1 month test-retest reliability. Autism Res 2016, 9: 1205-1215. © 2016 International Society for Autism Research, Wiley Periodicals, Inc.

Atypical cortical representation of peripheral visual space in children with an autism spectrum disorder

A key feature of early visual cortical regions is that they contain discretely organized retinotopic maps. Titration of these maps must occur through experience, and the fidelity of their spatial tuning will depend on the consistency and accuracy of the eye movement system. Anomalies in fixation patterns and the ballistics of eye movements are well documented in autism spectrum disorder (ASD), with off-center fixations a hallmark of the phenotype. We hypothesized that these atypicalities might affect the development of visuo-spatial maps and specifically that peripheral inputs might receive altered processing in ASD. Using high-density recordings of visual evoked potentials (VEPs) and a novel system-identification approach known as VESPA (visual evoked spread spectrum analysis), we assessed sensory responses to centrally and peripherally presented stimuli. Additionally, input luminance was varied to bias responsiveness to the magnocellular system, given previous suggestions of magnocellular-specific deficits in ASD. Participants were 22 ASD children (7-17 years of age) and 31 age- and performance-IQ-matched neurotypical controls. Both VEP and VESPA responses to central presentations were indistinguishable between groups. In contrast, peripheral presentations resulted in significantly greater early VEP and VESPA amplitudes in the ASD cohort. We found no evidence that anomalous enhancement was restricted to magnocellular-biased responses. The extent of peripheral response enhancement was related to the severity of stereotyped behaviors and restricted interests, cardinal symptoms of ASD. The current results point to differential visuo-spatial cortical mapping in ASD, shedding light on the consequences of peculiarities in gaze and stereotyped visual behaviors often reported by clinicians working with this population.

Electrophysiological evidence of atypical visual change detection in adults with autism

Although atypical change detection processes have been highlighted in the auditory modality in autism spectrum disorder (ASD), little is known about these processes in the visual modality. The aim of the present study was therefore to investigate visual change detection in adults with ASD, taking into account the salience of change, in order to determine whether this ability is affected in this disorder. Thirteen adults with ASD and 13 controls were presented with a passive visual three stimuli oddball paradigm. The findings revealed atypical visual change processing in ASD. Whereas controls displayed a vMMN in response to deviant and a novelty P3 in response to novel stimuli, patients with ASD displayed a novelty P3 in response to both deviant and novel stimuli. These results thus suggested atypical orientation of attention toward unattended minor changes in ASD that might contribute to the intolerance of change.

Atypical visual change processing in children with autism: an electrophysiological study

Children with Autism Spectrum Disorder (ASD) may display atypical behaviors in reaction to unattended changes that occur in all sensory modalities. Atypical automatic auditory change processing has been highlighted in ASD via the analysis of mismatch negativity (MMN). The present study investigated visual deviancy detection in children with ASD in order to determine whether unusual reactions to change operate in other sensory modalities. Twelve children with ASD were presented with a passive visual oddball paradigm using dynamic stimuli. Compared to controls, children with ASD showed an earlier visual mismatch response, suggesting a hypersensitivity to visual deviancy. This study is thus consistent with the hypothesis of the existence of "general" atypical change detection processing in children with ASD that might contribute to their intolerance of change.

Autobiographical accounts of sensing in Asperger syndrome and high-functioning autism

Sensory experiences in Asperger syndrome (AS) or high-functioning autism (HFA) were explored by qualitative content analysis of autobiographical texts by persons with AS/HFA. Predetermined categories of hyper- and hyposensitivity were applied to texts. Hypersensitivity consists of strong reactions and heightened apprehension in reaction to external stimuli, sometimes together with overfocused or unselective attention. It was common in vision, hearing, and touch. In contrast, hyposensitivity was frequent in reaction to internal and body stimuli such as interoception, proprioception, and pain. It consists of less registration, discrimination, and recognition of stimuli as well as cravings for specific stimuli. Awareness of the strong impact of sensitivity is essential for creating good environments and encounters in the context of psychiatric and other health care.

High-frequency oscillatory response to illusory contour in typically developing boys and boys with autism spectrum disorders

Illusory contour (IC) perception, a fruitful model for studying the automatic contextual integration of local image features, can be used to investigate the putative impairment of such integration in children with autism spectrum disorders (ASD). We used the illusory Kanizsa square to test how the phase-locked (PL) gamma and beta electroencephalogram (EEG) responses of typically developing (TD) children aged 3-7 years and those with ASD were modulated by the presence of IC in the image. The PL beta and gamma activity strongly differentiated between IC and control figures in both groups of children (IC effect). However, the timing, topography, and direction of the IC effect differed in TD and ASD children. Between 40 msec and 120 msec after stimulus onset, both groups demonstrated lower power of gamma oscillations at occipital areas in response to IC than in response to the control figure. In TD children, this relative gamma suppression was followed by relatively higher parieto-occipital gamma and beta responses to IC within 120-270 msec after stimulus onset. This second stage of IC processing was absent in children with ASD. Instead, their response to IC was characterized by protracted (40-270 msec) relative reduction of gamma and beta oscillations at occipital areas. We hypothesize that children with ASD rely more heavily on lower-order processing in the primary visual areas and have atypical later stage related to higher-order processes of contour integration.

Associating neural alterations and genotype in autism and fragile x syndrome: incorporating perceptual phenotypes in causal modeling

We have previously described (see companion paper, this issue) the utility of using perceptual signatures for defining and dissociating condition-specific neural functioning underlying early visual processes in autism and FXS. These perceptually-driven hypotheses are based on differential performance evidenced only at the earliest stages of visual information processing, mediated by local neural network functioning. In this paper, we first review how most large-scale neural models are unable to address atypical low-level perceptual functioning in autism, and then suggest how condition-specific, local neural endophenotypes (described in our companion paper) can be incorporated into causal models to infer target candidate gene or gene clusters that are implicated in autism's pathogenesis. The usefulness of such a translational research approach is discussed.