Multisensory Integration Deficits Research Articles

The dissociating effects of fear and disgust on multisensory integration in autism: evidence from evoked potentials.

Deficits in Multisensory Integration (MSI) in ASD have been reported repeatedly and have been suggested to be caused by altered long-range connectivity. Here we investigate behavioral and ERP correlates of MSI in ASD using ecologically valid videos of emotional expressions. In the present study, we set out to investigate the electrophysiological correlates of audiovisual MSI in young autistic and neurotypical adolescents. We employed dynamic stimuli of high ecological validity (500 ms clips produced by actors) that depicted fear or disgust in unimodal (visual and auditory), and bimodal (audiovisual) conditions. We report robust MSI effects at both the behavioral and electrophysiological levels and pronounced differences between autistic and neurotypical participants. Specifically, neurotypical controls showed robust behavioral MSI for both emotions as seen through a significant speed-up of bimodal response time (RT), confirmed by Miller's Race Model Inequality (RMI), with greater MSI effects for fear than disgust. Adolescents with ASD, by contrast, showed behavioral MSI only for fear. At the electrophysiological level, the bimodal condition as compared to the unimodal conditions reduced the amplitudes of the visual P100 and auditory P200 and increased the amplitude of the visual N170 regardless of group. Furthermore, a cluster-based analysis across all electrodes revealed that adolescents with ASD showed an overall delayed and spatially constrained MSI effect compared to controls. Given that the variables we measured reflect attention, our findings suggest that MSI can be modulated by the differential effects on attention that fear and disgust produce. We also argue that the MSI deficits seen in autistic individuals can be compensated for at later processing stages by (a) the attention-orienting effects of fear, at the behavioral level, and (b) at the electrophysiological level via increased attentional effort.

Multisensory integration deficits in Schizophrenia and Autism evidenced in behaviour but not event related potentials

The process of integrating information from different sensory channels, known as multisensory integration (MSI) was assessed in two disorders, Autism Spectrum Disorder (ASD) and Schizophrenia (SCZ). 32 healthy controls (HC), 35 SCZ patients, and 23 ASD patients performed an audiovisual (AV) synchronous target detection task while reaction time (RT) and scalp recorded electrophysiological (EEG) activity were measured. MSI in the AV condition resulted in faster and less variable RTs compared to the unimodal conditions. Using our novel bootstrap method, MSI gain was observed in 78 % of HC, 26 % of ASD, and 48 % of SCZ patients. At the neural level, MSI in the AV condition resulted in larger amplitude of sensory evoked responses and cognitive P3 response compared to the corresponding unimodal conditions. These neural effects of MSI were not related to the behavioural MSI gain identified at the individual level and could not explain the deficits in behavioural MSI of patient groups. In conclusion, a robust MSI gain deficit in RT was observed in both patient groups that was not reflected in early perceptual and cognitive electro-cortical responses, suggesting that behavioural MSI deficits in ASD and SCZ may arise at late processing stages such as response selection.

Sex Differences in Low-Level Multisensory Integration in Developmental Dyslexia.

Reading acquisition involves the integration of auditory and visual stimuli. Thus, low-level audiovisual multisensory integration might contribute to disrupted reading in developmental dyslexia. Although dyslexia is more frequently diagnosed in males and emerging evidence indicates that the neural basis of dyslexia might differ between sexes, previous studies examining multisensory integration did not evaluate potential sex differences nor tested its neural correlates. In the current study on 88 adolescents and young adults, we found that only males with dyslexia showed a deficit in multisensory integration of simple nonlinguistic stimuli. At the neural level, both females and males with dyslexia presented smaller differences in response to multisensory compared to those in response to unisensory conditions in the N1 and N2 components (early components of event-related potentials associated with sensory processing) than the control group. Additionally, in a subsample of 80 participants matched for nonverbal IQ, only males with dyslexia exhibited smaller differences in the left hemisphere in response to multisensory compared to those in response to unisensory conditions in the N1 component. Our study indicates that deficits of multisensory integration seem to be more severe in males than females with dyslexia. This provides important insights into sex-modulated cognitive processes that might confer vulnerability to reading difficulties.

Perception of audio-visual synchrony in infants at elevated likelihood of developing autism spectrum disorder.

Findings suggest that early deficits in multisensory integration may impair language development among infants with elevated likelihood of developing ASD. •Perceptual integration of auditory and visual cues within speech is important for language development. •Prior work suggests that children with ASD are less sensitive to the temporal synchrony within audio-visual speech. •In this study, infants at elevated likelihood of developing ASD showed a larger temporal binding window for adynamic social event (Speaking Face) than TD infants, suggesting less efficient multisensory integration.

Characterization of visual processing in temporomandibular disorders using functional magnetic resonance imaging.

Many patients with chronic pain report hypersensitivity not only to noxious stimuli, but also to other modalities including innocuous touch, sound, and light, possibly due to differences in the processing of these stimuli. The goal of this study was to characterize functional connectivity (FC) differences between subjects with temporomandibular disorders (TMD) and pain-free controls during a visual functional magnetic resonance imaging (fMRI) task that included an unpleasant, strobing visual stimulus. We hypothesized the TMD cohort would exhibit maladaptations in brain networks consistent with multisensory hypersensitivities observed in TMD patients. This pilot study included 16 subjects, 10 with TMD and 6 pain-free controls. Clinical pain was characterized using self-reported questionnaires. Visual task-based fMRI data were collected on a 3T MR scanner and used to determine differences in FC via group independent component analysis. Compared to controls, subjects with TMD exhibited abnormally increased FC between the default mode network and lateral prefrontal areas involved in attention and executive function, and impaired FC between the frontoparietal network and higher order visual processing areas. The results indicate maladaptation of brain functional networks, likely due to deficits in multisensory integration, default mode network function, and visual attentionandengendered by chronic pain mechanisms.

Multichannel Perception of Emotion in Speech, Voice, Facial Expression, and Gesture in Individuals With Autism: A Scoping Review.

Numerous studies have identified individuals with autism spectrum disorder (ASD) with deficits in unichannel emotion perception and multisensory integration. However, only limited research is available on multichannel emotion perception in ASD. The purpose of this review was to seek conceptual clarification, identify knowledge gaps, and suggest directions for future research. We conducted a scoping review of the literature published between 1989 and 2021, following the 2005 framework of Arksey and O'Malley. Data relating to study characteristics, task characteristics, participant information, and key findings on multichannel processing of emotion in ASD were extracted for the review. Discrepancies were identified regarding multichannel emotion perception deficits, which are related to participant age, developmental level, and task demand. Findings are largely consistent regarding the facilitation and compensation of congruent multichannel emotional cues and the interference and disruption of incongruent signals. Unlike controls, ASD individuals demonstrate an overreliance on semantics rather than prosody to decode multichannel emotion. The existing literature on multichannel emotion perception in ASD is limited, dispersed, and disassociated, focusing on a variety of topics with a wide range of methodologies. Further research is necessary to quantitatively examine the impact of methodological choice on performance outcomes. An integrated framework of emotion, language, and cognition is needed to examine the mutual influences between emotion and language as well as the cross-linguistic and cross-cultural differences. https://doi.org/10.23641/asha.19386176.

Maladaptive reorganization following SCI: The role of body representation and multisensory integration.

In this review we focus on maladaptive brain reorganization after spinal cord injury (SCI), including the development of neuropathic pain, and its relationship with impairments in body representation and multisensory integration. We will discuss the implications of altered sensorimotor interactions after SCI with and without neuropathic pain and possible deficits in multisensory integration and body representation. Within this framework we will examine published research findings focused on the use of bodily illusions to manipulate multisensory body representation to induce analgesic effects in heterogeneous chronic pain populations and in SCI-related neuropathic pain. We propose that the development and intensification of neuropathic pain after SCI is partly dependent on brain reorganization associated with dysfunctional multisensory integration processes and distorted body representation. We conclude this review by suggesting future research avenues that may lead to a better understanding of the complex mechanisms underlying the sense of the body after SCI, with a focus on cortical changes.

People With High Autistic Traits Show Fewer Consensual Crossmodal Correspondences Between Visual Features and Tastes.

Crossmodal correspondences between visual features (e.g., color/shape) and tastes have been extensively documented in recent years. Visual colors and shapes have been shown to consensually match to specific tastes. Meanwhile, individuals with autism spectrum disorder are reported to have atypical sensory processing and deficits in multisensory integration. However, the influence of autistic traits on the formation of such correspondences is relatively unknown. Here, we examined whether autistic traits could influence visual–taste associations using an online questionnaire survey among Japanese participants. The results showed that the participants exhibited strong color–taste, shape–taste, and shape–color associations, and the proportions of choosing the consensual color–taste/shape–color associations were significantly associated with autistic traits. The participants with higher autistic quotient scores chose fewer of the consensual color–taste/shape–color associations while there was no difference in choosing shape–taste associations. We interpreted the results as statistical learning with a reduced prior knowledge effect in participants with higher autistic quotient scores.

Striatal GABA level is associated with sensory integration ability in individuals with low levels of negative schizotypy

Recent studies suggest that altered gamma-aminobutyric acidergic (GABAergic) function may result in multisensory integration deficits in schizophrenia. However, it is unclear whether the GABA level is abnormal in individuals with high levels of schizotypal traits and how it would correlate with sensory integration ability in these individuals. This study aimed to compare the GABA level between individuals with high and low levels of negative schizotypy, and examine the relationship between GABA levels and sensory integration ability in each group. In vivo GABA+ and N-acetylaspartate (NAA) levels in the striatum were measured using proton magnetic resonance imaging in 19 participants with high levels of negative schizotypy and 21 participants with low levels of negative schizotypy. The Sensory Integration subscale of the abridged version of the Cambridge Neurological Inventory was used. We examined the group differences in GABA+/NAA levels, and the correlation between striatal GABA+/NAA levels and sensory integration ability in each group. The two groups showed comparable levels of in-vivo GABA+/NAA. In-vivo GABA+/NAA levels were negatively correlated with sensory integration score in participants with low levels of negative schizotypy, but not in participants with high levels of negative schizotypy. Our findings indicate that the increased GABA level is correlated with better sensory integration ability in individuals with low levels of negative schizotypy, implicating the role of GABAergic function in multisensory integration. Unlike schizophrenia patients, individuals with high levels of schizotypy do not exhibit any abnormality in their GABAergic system and sensory integration ability.

Gamma oscillation: An important biomarker reflecting multisensory integration deficits in autism spectrum disorders

<p id="C2">Multi-sensory integration (MSI) refers to a comprehensive process of selecting, connecting, unifying, and interpreting different sensory information. It involves coordination among various brain regions to achieve temporal binding of multiple sensory information and global predictive encoding. On the other hand, gamma oscillation plays vital roles in MSI, due to its versatile functions in reflecting excitation/inhibition balance of interneuron, implementing temporal binding of multi-sensory information, and participating in global predictive encoding via a cross-frequency coupling mechanism. Multisensory integration deficits are typical symptoms of patients with autism spectrum disorders (ASD). Research shows that patients with ASD usually exhibit abnormal gamma oscillations caused by structural and functional abnormalities in GABA interneurons. In turn, these abnormal gamma oscillations disrupt temporal binding and predictive encoding, and eventually lead to MSI deficits in ASD. As a result, future research could use gamma rhythm neural oscillation as a biofeedback indicator, in combination with non-invasive and reversible intervention technologies, to develop scientific and systematic clinical intervention treatments.

Late attentional processes potentially compensate for early perceptual multisensory integration deficits in children with autism: evidence from evoked potentials

Sensory processing deficits and altered long-range connectivity putatively underlie Multisensory Integration (MSI) deficits in Autism Spectrum Disorder (ASD). The present study set out to investigate non-social MSI stimuli and their electrophysiological correlates in young neurotypical adolescents and adolescents with ASD. We report robust MSI effects at behavioural and electrophysiological levels. Both groups demonstrated normal behavioural MSI. However, at the neurophysiological level, the ASD group showed less MSI-related reduction of the visual P100 latency, greater MSI-related slowing of the auditory P200 and an overall temporally delayed and spatially constrained onset of MSI. Given the task design and patient sample, and the age of our participants, we argue that electro-cortical indices of MSI deficits in ASD: (a) can be detected in early-adolescent ASD, (b) occur at early stages of perceptual processing, (c) can possibly be compensated by later attentional processes, (d) thus leading to normal MSI at the behavioural level.

Multisensory Audiovisual Processing in Children With a Sensory Processing Disorder (II): Speech Integration Under Noisy Environmental Conditions.

Background: There exists a cohort of children and adults who exhibit an inordinately high degree of discomfort when experiencing what would be considered moderate and manageable levels of sensory input. That is, they show over-responsivity in the face of entirely typical sound, light, touch, taste, or smell inputs, and this occurs to such an extent that it interferes with their daily functioning and reaches clinical levels of dysfunction. What marks these individuals apart is that this sensory processing disorder (SPD) is observed in the absence of other symptom clusters that would result in a diagnosis of Autism, ADHD, or other neurodevelopmental disorders more typically associated with sensory processing difficulties. One major theory forwarded to account for these SPDs posits a deficit in multisensory integration, such that the various sensory inputs are not appropriately integrated into the central nervous system, leading to an overwhelming sensory-perceptual environment, and in turn to the sensory-defensive phenotype observed in these individuals.Methods: We tested whether children (6–16 years) with an over-responsive SPD phenotype (N = 12) integrated multisensory speech differently from age-matched typically-developing controls (TD: N = 12). Participants identified monosyllabic words while background noise level and sensory modality (auditory-alone, visual-alone, audiovisual) were varied in pseudorandom order. Improved word identification when speech was both seen and heard compared to when it was simply heard served to index multisensory speech integration.Results: School-aged children with an SPD show a deficit in the ability to benefit from the combination of both seen and heard speech inputs under noisy environmental conditions, suggesting that these children do not benefit from multisensory integrative processing to the same extent as their typically developing peers. In contrast, auditory-alone performance did not differ between the groups, signifying that this multisensory deficit is not simply due to impaired processing of auditory speech.Conclusions: Children with an over-responsive SPD show a substantial reduction in their ability to benefit from complementary audiovisual speech, to enhance speech perception in a noisy environment. This has clear implications for performance in the classroom and other learning environments. Impaired multisensory integration may contribute to sensory over-reactivity that is the definitional of SPD.

T26. VISUO-TACTILE TRANSFER AND AUDIO-VISUAL INTEGRATION IMPAIRMENT AS A NEW VULNERABILITY MARKER IN CHILDREN-AT-RISK OF SCHIZOPHRENIA, BIPOLAR DISORDER OR RECURRENT DEPRESSIVE DISORDER

BackgroundMajor psychiatric disorders (MPD) such as schizophrenia, bipolar disorder and recurrent major depression have shared neurodevelopmental vulnerability due to early neuronal and sensory defect as revealed by sensory and cognitive endophenotypes observed in our cohorts (e.g. Gagné et al., Schizophr. Res., 2019). There is considerable evidence that a harmonious self-development - known to be disrupted in MPDs - requires a synchronized multisensory perception and an adequate integration of sensory afferences (e.g. tactile, visual, auditory and proprio / interoception) with cognition. Early impairment in intermodal transfer (IMT) and multisensory integration (MSI) may jeopardize a stable and unified self’s and world’s representation and then would undermine self-development and represent a risk factor for MPD. IMT is the capability to transfer a percept coming exclusively from a sensory modality (e.g. tactile) to another modality (e.g. visual). MSI is the ability to integrate sensory inputs from different modalities (e.g. visual and auditory) to have a better information processing. This study shows that impairment in IMT/MSI may be a vulnerability marker in children genetically at-risk.MethodsSample: Forty-four offspring (21 girls) of patients suffering from a MPD and thus genetically at-risk for MPD (GatR) aged from 9–15 years old (mean age = 12.06) were recruited from the cohort study INTERCEPT through the HoPE program of the CIUSSS de la Capitale-Nationale. Twenty-five controls (19 girls) with no family history of MPD and no DSM-V disorder aged from 9–15 years old (mean age = 12.87) were recruited using advertisements or control bank.IMT Task:Each condition has 12 trials and the shapes are hidden from sight during palpation.- T-T condition: The subject has to palpate a 3D target shape for 10s and must then recognize it by touch from among a distractor.- Condition T-V: The subject has to palpate a 3D target shape for 10s and must then recognize it visually from among a distractor.- V-T Condition: A 3D target shape is presented visually for 10s and the subject must then recognize it by touch from among a distractor.MSI Task: - Simple reaction time (RT) task comprising 80 trials with unimodal stimuli (Auditory OR Visual) and 40 trials with AV (Auditory and Visual simultaneously) multimodal stimuli presented randomly.- The Race model calculates the expected response probability for each RT knowing that AV RT could not be shorter than the shorter unimodal RT, if the sensory modalities are indeed separated channels (no MSI).- RTs shorter than those predicted by the Race model (best unimodal RT) are presumed to show multisensory facilitation which reflects MSI. The percentage of AV facilitation (AV – Race) is calculated for each reaction time.ResultsIMT task: When compared to controls, GatR were impaired in the three conditions (T-T: 9.77 vs. 10.32, T-V: 9.89 vs. 9.96, V-T: 9,11 vs. 9.92) with significant impairments both for T-T (t(60.53) = 2.18, p = 0.017) and V-T (t (57.28) = 2.33, p = 0.012) conditions.MSI task: GatR showed a deficit in MSI for almost all RT ranges (except for a peak at 185 ms), while control participants showed MSI facilitation for ranges from 150 to 200 ms.DiscussionDevelopmentally genetically high-risk children would show significant impairments both in IMT and MSI that might enter into the group of indicators of brain dysfunctions, or risk endophenotypes, that both children at risk and adult patients carry (Paccalet et al., Schizophr. Res., 2016; Maziade, New Eng J Medicine, 2017). In addition, the two tasks would be valid and sensitive to the early sensory alterations in self-development. Finally, the battery is brief, user-friendly and playful for children.

4.70 SENSORIMOTOR INTEGRATION AND ABC-MOVEMENT 2 ASSESSMENT IN ABNORMAL CONNECTIVITY SPECTRUM DISORDERS (ASD, ADHD, TOURETTE’S DISORDER) VERSUS CONTROL SUBJECTS: A CROSS-SECTIONAL STUDY

Multisensory integration deficits in children may affect postural control in static/dynamic conditions. Standing balance requires the ability to integrate sensory inputs form visual, somatosensory, and vestibular systems. Although previous studies have examined balance performances in developmental disorders, sensorimotor integration processes have not been compared in different diagnostic groups. In our study, we intend to perform a cross-sectional analysis of postural strategies under 6 sensory conditions in diagnostic groups (ASD, ADHD, and Tourette’s disorder) compared with control subjects.

Sensory-to-Cognitive Systems Integration Is Associated With Clinical Severity in Autism Spectrum Disorder

Impaired multisensory integration in autism spectrum disorder (ASD) may arise from functional dysconnectivity among brain systems. Our study examines the functional connectivity integration between primary modal sensory regions and heteromodal processing cortex in ASD, and whether abnormalities in network integration relate to clinical severity. We studied a sample of 55 high-functioning ASD and 64 healthy control (HC) male children and adolescents (total n= 119, age range 7-18 years). Stepwise functional connectivity analysis (SFC) was applied to resting state functional magnetic resonance images (rsfMRI) to characterize the connectivity paths that link primary sensory cortices to higher-order brain cognitive functional circuits and to relate alterations in functional connectivity integration with three clinical scales: Social Communication Questionnaire, Social Responsiveness Scale, and Vineland Adaptive Behavior Scales. HC displayed typical functional connectivity transitions from primary sensory systems to association areas, but the ASD group showed altered patterns of multimodal sensory integration to heteromodal systems. Specifically, compared to the HC group, the ASD group showed the following: (1) hyperconnectivity in the visual cortex at initial link step distances; (2) hyperconnectivity between sensory unimodal regions and regions of the default mode network; and (3) hypoconnectivity between sensory unimodal regions and areas of the fronto-parietal and attentional networks. These patterns of hyper- and hypoconnectivity were associated with increased clinical severity in ASD. Networkwise reorganization in high-functioning ASD individuals affects strategic regions of unimodal-to-heteromodal cortical integration predicting clinical severity. In addition, SFC analysis appears to be a promising approach for studying the neural pathophysiology of multisensory integration deficits in ASD.

Children can optimally integrate multisensory information after a short action-like mini game training.

Combining information across different sensory modalities is of critical importance for the animal's survival and a core feature of human's everyday life. In adulthood, sensory information is often integrated in a statistically optimal fashion, so that the combined estimates of two or more senses are more reliable than the best single one. Several studies have shown that young children use one sense to calibrate the others, which results in unisensory dominance and undermines their optimal multisensory integration abilities. In this study we trained children aged 4-5years with action-like mini games, to determine whether it could improve their multisensory as well as their visuo-spatial skills. Multisensory integration abilities were assessed using a visuo-haptic size discrimination task, while visuo-spatial attention skills were investigated using a multiple object tracking task (MOT). We found that 2-weeks training were sufficient to observe both optimal multisensory integration and visuo-spatial enhancements selectively in the group trained with action-like mini games. This plastic change persisted up to 3months, as assessed in a follow-up. Our novel findings reveal that abilities that are commonly known to emerge in late childhood can be promoted in younger children through action-like mini games and have long-lasting effects. Our data have clinical implications, in that they suggest that specific trainings could potentially help children with multisensory integration deficits.

Being socially uninterested versus not having social prediction skills: The impact of multisensory integration deficits on social skills in autism

Abstract Jaswal &amp; Akhtar in their target article convincingly argue that subjects with autism do not have diminished social motivation. However, they still recognize that autistic people behave socially in an unusual way. Why? Here we suggest that these behaviours are the results of a multisensory integration deficit. Viewed from this perspective, the assumption that autistic people's unusual behaviours indicate diminished social motivation has to be replaced by the one that they have diminished social prediction skills.

Psychophysical Evaluation of Sensory Reweighting in Bilateral Vestibulopathy.

Perception of spatial orientation is thought to rely on the brain’s integration of visual, vestibular, proprioceptive, and somatosensory signals, as well as internal beliefs. When one of these signals breaks down, such as the vestibular signal in bilateral vestibulopathy, patients start compensating by relying more on the remaining cues. How these signals are reweighted in this integration process is difficult to establish, since they cannot be measured in isolation during natural tasks, are inherently noisy, and can be ambiguous or in conflict. Here, we review our recent work, combining experimental psychophysics with a reverse engineering approach, based on Bayesian inference principles, to quantify sensory noise levels and optimal (re)weighting at the individual subject level, in both patients with bilateral vestibular deficits and healthy controls. We show that these patients reweight the remaining sensory information, relying more on visual and other nonvestibular information than healthy controls in the perception of spatial orientation. This quantification approach could improve diagnostics and prognostics of multisensory integration deficits in vestibular patients, and contribute to an evaluation of rehabilitation therapies directed toward specific training programs.

A Computational Analysis of Neural Mechanisms Underlying the Maturation of Multisensory Speech Integration in Neurotypical Children and Those on the Autism Spectrum.

Failure to appropriately develop multisensory integration (MSI) of audiovisual speech may affect a child's ability to attain optimal communication. Studies have shown protracted development of MSI into late-childhood and identified deficits in MSI in children with an autism spectrum disorder (ASD). Currently, the neural basis of acquisition of this ability is not well understood. Here, we developed a computational model informed by neurophysiology to analyze possible mechanisms underlying MSI maturation, and its delayed development in ASD. The model posits that strengthening of feedforward and cross-sensory connections, responsible for the alignment of auditory and visual speech sound representations in posterior superior temporal gyrus/sulcus, can explain behavioral data on the acquisition of MSI. This was simulated by a training phase during which the network was exposed to unisensory and multisensory stimuli, and projections were crafted by Hebbian rules of potentiation and depression. In its mature architecture, the network also reproduced the well-known multisensory McGurk speech effect. Deficits in audiovisual speech perception in ASD were well accounted for by fewer multisensory exposures, compatible with a lack of attention, but not by reduced synaptic connectivity or synaptic plasticity.

Temporal synchrony and audiovisual integration of speech and object stimuli in autism

BackgroundIndividuals with Autism Spectrum Disorders (ASD) have been shown to have multisensory integration deficits, which may lead to problems perceiving complex, multisensory environments. For example, understanding audiovisual speech requires integration of visual information from the lips and face with auditory information from the voice, and audiovisual speech integration deficits can lead to impaired understanding and comprehension. While there is strong evidence for an audiovisual speech integration impairment in ASD, it is unclear whether this impairment is due to low level perceptual processes that affect all types of audiovisual integration or if it is specific to speech processing. MethodHere, we measure audiovisual integration of basic speech (i.e., consonant-vowel utterances) and object stimuli (i.e., a bouncing ball) in adolescents with ASD and well-matched controls. We calculate a temporal window of integration (TWI) using each individual’s ability to identify which of two videos (one temporally aligned and one misaligned) matches auditory stimuli. The TWI measures tolerance for temporal asynchrony between the auditory and visual streams, and is an important feature of audiovisual perception. ResultsWhile controls showed similar tolerance of asynchrony for the simple speech and object stimuli, individuals with ASD did not. Specifically, individuals with ASD showed less tolerance of asynchrony for speech stimuli compared to object stimuli. In individuals with ASD, decreased tolerance for asynchrony in speech stimuli was associated with higher ratings of autism symptom severity. ConclusionsThese results suggest that audiovisual perception in ASD may vary for speech and object stimuli beyond what can be accounted for by stimulus complexity.