Early and late stage processing abnormalities in autism spectrum disorders: An ERP study

Preliminary observations on the associations between sensory processing abnormalities and event-related potentials in adults with autism spectrum disorder

Aim

Autism spectrum disorder (ASD) is a neurodevelopmental disorder that is thought to involve a variety of neurophysiological characteristics. Event-related potentials (ERPs) reflect cognitive functions in the brain's cognitive processing. In this study, we investigated differences in P300 and N100 of ERPs between ASD and typically developing groups and focused on the relationship between the components of ERPs and measures of autistic traits and sensory processing characteristics.

Methods

ERPs were measured in 96 subjects in the ASD group and 62 subjects in the age- and sex-adjusted typically developing group. Correlations between each component and the scores of the Autism-Spectrum Quotient Japanese version (AQ-J) and the Adolescent and Adult Sensory Profile (AASP) were also evaluated.

Results

The ASD group showed a significant decrease in the amplitude of N100 at C3. Furthermore, a negative correlation was found between lower amplitude at C3 of N100 and low registered sensory scores in both groups.

Conclusion

Our findings imply that the N100 amplitude at C3 could be a potential indicator for examining the neurophysiological traits of ASD; however, these results should be interpreted with caution due to their preliminary nature. These tentative insights into sensory processing anomalies may be discernible in specific subsets of the ASD population, providing a foundation for future investigative pathways.

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.

Attribution of intentions in autism spectrum disorder: A study of event-related potentials

Autism spectrum disorder (ASD) is characterized by social cognition deficits, including difficulties inferring the intentions of others. Although deficits in attribution of intentions (AI) have been consistently replicated in ASD, their exact nature remains unexplored. Here we registered the electrophysiological correlates of a nonverbal social cognition task to investigate AI in autistic adults. Twenty-one male autistic adults and 30 male neurotypical volunteers performed a comic strips task depicting either intentional action (AI) or physical causality with or without human characters, while their electroencephalographic signal was recorded. Compared to neurotypical volunteers, autistic participants were significantly less accurate in correctly identifying congruence in the AI condition, but not in the physical causality conditions. In the AI condition a bilateral posterior positive event-related potential (ERP) occurred 200-400 ms post-stimulus (the ERP intention effect) in both groups. This waveform comprised a P200 and a P300 component, with the P200 component being larger for the AI condition in neurotypical volunteers but not in autistic individuals, who also showed a longer latency for this waveform. Group differences in amplitude of the ERP intention effect only became evident when we compared autistic participants to a subgroup of similarly performing neurotypical participants, suggesting that the atypical ERP waveform in ASD is an effect of group, rather than a marker of low-task performance. Together, these results suggest that the lower accuracy of the ASD group in the AI task may result from impaired early attentional processing and contextual integration of socially relevant cues. LAY SUMMARY: To understand why autistic people have difficulties in inferring others' intentions, we asked participants to judge the congruence of the endings of comic strips depicting either intentional actions (e.g., fetching a chair to reach for something) or situations solely following physical rules (e.g., an apple falling on someone's head), while their electrical brain activity was recorded. Autistic individuals had more difficulties in inferring intentions than neurotypical controls, which may reflect impaired attention and contextual integration of social cues.

Enhancing neural markers of attention in children with ADHD using a digital therapeutic

Attention deficit hyperactivity disorder (ADHD) is a prevalent neurodevelopmental condition characterized by diminished attentional control. Critically, these difficulties are related to negative consequences in real-life functioning both during development and into adulthood. There is now growing evidence that modulating the underlying neural circuits related to attention can improve behavior and brain function in children with ADHD. We have previously shown that game-based digital therapeutics targeting a key neural marker of attention-midline frontal theta (MFT)-yield positive effects on attentional control in several populations. However, the effects of such digital therapeutics in children with ADHD and no other comorbidities has not been yet examined. To address this gap, we assessed a sample of 25 children with ADHD (8-12 years old) on neural, behavioral, and clinical metrics of attention before and after a 4-week at-home intervention on an iPad targeting MFT circuitry. We found that children showed enhancements on a neural measure of attention (MFT power), as well as on objective behavioral measures of attention and parent reports of clinical ADHD symptoms. Importantly, we observed relationships between the neural and behavioral cognitive improvements, demonstrating that those children who showed the largest intervention-related neural gains were also those that improved the most on the behavioral tasks indexing attention. These findings provide support for using targeted, digital therapeutics to enhance multiple features of attentional control in children with ADHD. Study registration: ClinicalTrials.gov registry (NCT03844269) https://clinicaltrials.gov/ct2/show/NCT03844269.

Unconstrained multivariate EEG decoding can help detect lexical-semantic processing in individual children

In conditions such as minimally-verbal autism, standard assessments of language comprehension are often unreliable. Given the known heterogeneity within the autistic population, it is crucial to design tests of semantic comprehension that are sensitive in individuals. Recent efforts to develop neural signals of language comprehension have focused on the N400, a robust marker of lexical-semantic violation at the group level. However, homogeneity of response in individual neurotypical children has not been established. Here, we presented 20 neurotypical children with congruent and incongruent visual animations and spoken sentences while measuring their neural response using electroencephalography (EEG). Despite robust group-level responses, we found high inter-individual variability in response to lexico-semantic anomalies. To overcome this, we analysed our data using temporally and spatially unconstrained multivariate pattern analyses (MVPA), supplemented by descriptive analyses to examine the timecourse, topography, and strength of the effect. Our results show that neurotypical children exhibit heterogenous responses to lexical-semantic violation, implying that any application to heterogenous disorders such as autism spectrum disorder will require individual-subject analyses that are robust to variation in topology and timecourse of neural responses.

Pathogenetical and Neurophysiological Features of Patients with Autism Spectrum Disorder: Phenomena and Diagnoses

Autism spectrum disorder (ASD) is a neurodevelopmental disorder that is accompanied by social deficits, repetitive and restricted interests, and altered brain development. The majority of ASD patients suffer not only from ASD itself but also from its neuropsychiatric comorbidities. Alterations in brain structure, synaptic development, and misregulation of neuroinflammation are considered risk factors for ASD and neuropsychiatric comorbidities. Electroencephalography has been developed to quantitatively explore effects of these neuronal changes of the brain in ASD. The pineal neurohormone melatonin is able to contribute to neural development. Also, this hormone has an inflammation-regulatory role and acts as a circadian key regulator to normalize sleep. These functions of melatonin may play crucial roles in the alleviation of ASD and its neuropsychiatric comorbidities. In this context, this article focuses on the presumable role of melatonin and suggests that this hormone could be a therapeutic agent for ASD and its related neuropsychiatric disorders.

Auditory event-related potentials demonstrate early cognitive impairment in children with subclinical hypothyroidism

Background The aim of this study was to examine the cognitive functions of children with subclinical hypothyroidism (SH) and healthy children with the use of auditory event-related potentials (AERPs) and neuropsychological tests. Methods Twenty children aged between 8 and 17 years, diagnosed with SH, and 20 age-matched healthy controls were included in this study. A classical auditory oddball paradigm was applied during the electroencephalography (EEG) recordings, and event-related potentials (ERPs) were evaluated between the 0.5- and 20-Hz frequency intervals. P1, N1, P2, N2 and P3 amplitudes and latencies were measured in Fz, FCz, Cz, CPz, Pz and Oz electrodes. Additionally, a number of neuropsychological tests evaluating the reaction time and various cognitive functions were carried out. Results In children with SH, P3 amplitudes in FCz, Cz and CPz electrodes were significantly lower than those in controls (p < 0.05). In addition to this, the P1N1 and N1P2 peak-to-peak amplitude values were also found to be smaller for children with SH than controls (p < 0.05). With regard to the neuropsychological tests, no significant difference was observed between the SH and control groups on any of the cognitive test parameters, reaction time or correct response rates. Conclusions In the present study, while children with SH did not differ from controls with respect to their cognitive functions evaluated via neuropsychological tests, cognitive differences were detected via electrophysiological investigations. This result implies that implicit changes in cognition which are not yet overtly reflected on neuropsychological tests may be detected at an early stage in children with SH.

Diagnostic Assessment Techniques and Non-Invasive Biomarkers for Autism Spectrum Disorder

Autism spectrum disorder (ASD) is a complex heterogeneous neurological disorder that has led to a spectrum of diagnosis techniques. The screening instruments, medical and technological tools initiate the diagnosis process. Clinicians and psychologists propose therapies depending on the examination done by these methodologies. The literature has accounted dozens of diagnostic methods and alternative and complementary therapies but still lack in highlighting the proper biomarker for early detection and intervention. The emerging multi-modal neuro-imaging techniques have correlated the brain's functional and structural measures and diagnosed ASD with more sensitivity than individual approaches. The purpose of this review article is: (i) to provide an overview of the emerging ASD diagnosis methods and different markers and; (ii) to present the idea of integrating all the individual methods in to a multi-modal diagnostic system to enhance detection sensitivity. This system possesses the potential to diagnose and predict ASD clinically, neurologically & objectively with high detection sensitivity.

Minimally-verbal children with autism show deficits in theta and gamma oscillations during processing of semantically-related visual information

To acquire language, children must build phonemic representations of their native language, learn to associate auditory words to visual objects and assemble a lexicon. It is not clear however, whether the limited linguistic ability seen in minimally-verbal (MV) children with Autism Spectrum Disorder (ASD) relates to deficits in cortical representation of an object and/or in linking an object to its semantic information. This EEG-based study investigated neural mechanisms underlying visual processing of common objects in MV-ASD and control children. Ten MV-ASD children, 4- to 7- years-old and 15 age/gender-matched controls, were presented with a picture-word matching paradigm. Time-frequency analyses were conducted at the sources generating the event-related responses at both early and late visual processing. Permutation testing identified spectral power and phase coherence clusters that significantly differed between the groups. As compared to controls, MV-ASD children exhibited smaller amplitudes and longer source latencies; decreased gamma and theta power with less theta phase coherence in occipital regions, and reduced frontal gamma power. Our results confirm that visual processing is altered in MV-ASD children and suggest that some of the linguistic differences observed in these children arise from impaired object/label cortical representations and reduced allocation of attention, which would impact lexical acquisition.