Visual attention in autism families: ‘unaffected’ sibs share atypical frontal activation

Background: In addition to their more clinically evident abnormalities of social cognition, people with autism spectrum conditions (ASC) manifest perturbations of attention and sensory perception which may offer insights into the underlying neural abnormalities. Similar autistic traits in ASC relatives without a diagnosis suggest a continuity between clinically affected and unaffected family members

Change detection in children with autism: an auditory event-related fMRI study

Autism involves impairments in communication and social interaction, as well as high levels of repetitive, stereotypic and ritualistic behaviours, and extreme resistance to change. This latter dimension, whilst required for a diagnosis, has received less research attention. We hypothesise that this extreme resistance to change in autism is rooted in atypical processing of unexpected stimuli. We tested this using auditory event-related fMRI to determine regional brain activity associated with passive detection of infrequently occurring frequency-deviant and complex novel sounds in a no-task condition. Participants were twelve 10 to 15-year-old children with autism, and a group of 12 age- and sex-matched healthy controls

Validation of the repetitive and restricted behaviour scale in autism spectrum disorders

Repetitive and restricted behaviours represent a common problem for various psychiatric syndromes, especially in autistic spectrum disorders, and they include a wide range of heterogeneous behavioural manifestations. An accurate and standardized description of these behaviours is needed to advance the understanding of this complex and heterogeneous clinical dimension of autism. The present article reports the reliability and validity studies of a new assessment scale: the repetitive and restricted behaviour scale. 145 subjects with autism spectrum disorders were assessed using the RRB scale. The RRB scale has good interrater reliability, internal consistency and content validity. Factorial analysis produced four clinically meaningful factors, i.e. “sensorimotor stereotypies”, “reaction to change”, “restricted behaviours” and “modulation insufficiency”. The RRB scale has good psychometric qualities and constitutes a real breakthrough towards a neurofunctional approach to autistic disorders. It should be valuable for research and treatment, and in clinical practice

Les compléments neurophysiologiques du diagnostic

Neurophysiological complements of autism diagnosis Research presented show relationships between behavioral and cognitive disorders and underlying cerebral functional abnormalities, on the basis of non invasive electrophysiological investigations (electroencephalography, cortical evoked potentials). Three types of disturbances are studied: sleep problems, intolerance to change and atypical visual processing of human faces. The complementarity of clinical and neurophysiological approaches is crucial at the levels of functional diagnosis, therapeutic and educative interventions

Neural repetition suppression to vocal and non-vocal sounds

Adaptation to the sensory environment is essential in everyday life, to anticipate future events and quickly detect and respond to changes; and to distinguish vocal variations in congeners, for communication. The aim of the current study was to explore the effects of the nature (vocal/non-vocal) of the information to be encoded, on the establishment of auditory regularities. In electrophysiology, neural adaptation is measured by the ‘Repetition Positivity’ (RP), which refers to an increase in positive potential, with the increasing number of repetitions of a same stimulus. The RP results from the combined variation of several ERP components; the P1, the first positivity (∼100 ms) may reflect the onset of repetition effects. We recorded auditory evoked potentials during a roving paradigm in which trains of 4, 8 or 16 repetitions of the same stimulus were presented. Sequences of vocal and non-vocal complex stimuli were delivered, to study the influence of the type of stimulation on the characteristics of the brain responses. The P1 to each train length, and the RP responses were recorded between 90 and 200 ms, reflecting adaptation for both vocal and non-vocal stimuli. RP was not different between vocal and non-vocal sequences (in latency, amplitude and spatial organization) and was found to be similar to that found in previous studies using pure tones, suggesting that the repetition suppression phenomena is somehow independent of the nature of the stimulus. However, results showed faster stabilization of the P1 amplitude for non vocal stimuli than for vocal stimuli, which require more repetitions. This revealed different dynamics for the establishment of regularity encoding for non-vocal and vocal stimuli, indicating that the richness of vocal sounds may require further processing before full neural adaptation occurs

Functional morphological imaging of autism spectrum disorders: Current position and theories proposed

AbstractAutism is a pervasive disorder of childhood development. Polymorphous clinical profiles combining various degrees of communication and social interaction with restricted and stereotyped behaviour are grouped under the heading of ‘autism spectrum disorders’ (ASD). Many teams are trying to pick out the underlying cerebral abnormalities in order to understand the neuronal networks involved in relationships with others. Here we review the morphological, spectroscopic and functional abnormalities in the amygdala-hippocampal circuit, the caudate nuclei, the cerebellum, and the frontotemporal regions, which have been described in subjects with ASD. White matter abnormalities have also been described in diffusion tensor imaging, leading to suspected damage to the subjacent neural networks, such as mirror neurones or the social brain

Disorder-specific functional abnormalities during sustained attention in youth with Attention Deficit Hyperactivity Disorder (ADHD) and with Autism

Attention Deficit Hyperactivity Disorder (ADHD) and Autism Spectrum Disorder (ASD) are often comorbid and share behavioural-cognitive abnormalities in sustained attention. A key question is whether this shared cognitive phenotype is based on common or different underlying pathophysiologies. To elucidate this question, we compared 20 boys with ADHD to 20 age and IQ matched ASD and 20 healthy boys using functional magnetic resonance imaging (fMRI) during a parametrically modulated vigilance task with a progressively increasing load of sustained attention. ADHD and ASD boys had significantly reduced activation relative to controls in bilateral striato–thalamic regions, left dorsolateral prefrontal cortex (DLPFC) and superior parietal cortex. Both groups also displayed significantly increased precuneus activation relative to controls. Precuneus was negatively correlated with the DLPFC activation, and progressively more deactivated with increasing attention load in controls, but not patients, suggesting problems with deactivation of a task-related default mode network in both disorders. However, left DLPFC underactivation was significantly more pronounced in ADHD relative to ASD boys, which furthermore was associated with sustained performance measures that were only impaired in ADHD patients. ASD boys, on the other hand, had disorder-specific enhanced cerebellar activation relative to both ADHD and control boys, presumably reflecting compensation. The findings show that ADHD and ASD boys have both shared and disorder-specific abnormalities in brain function during sustained attention. Shared deficits were in fronto–striato–parietal activation and default mode suppression. Differences were a more severe DLPFC dysfunction in ADHD and a disorder-specific fronto–striato–cerebellar dysregulation in ASD

Attitudes of the autism community to early autism research

Investigation into the earliest signs of autism in infants has become a significant sub-field of autism research. This work invokes specific ethical concerns such as: use of ‘at-risk’ language; communicating study findings to parents; and the future perspective of enrolled infants when they reach adulthood. The current study aimed to ground this research field in an understanding of the perspectives of members of the autism community. Following focus groups to identify topics, an online survey was distributed to autistic adults, parents of children with autism, and practitioners in health and education settings across eleven European countries. Survey respondents (n=2317) were positively disposed towards early autism research and there was significant overlap in their priorities for the field, and preferred language to describe infant research participants. However there were also differences including overall less favourable endorsement of early autism research by autistic adults relative to other groups and a dislike of the phrase ‘at-risk’ to describe infant participants, in all groups except healthcare practitioners. The findings overall indicate that the autism community in Europe is supportive of early autism research. Researchers should endeavour to maintain this by continuing to take community perspectives into account

Measuring the Behavioral Response to Spatial Audio within a Multi-Modal Virtual Reality Environment in Children with Autism Spectrum Disorder

Virtual Reality (VR) has been an active area of research in the development of interactive interventions for individuals with autism spectrum disorder (ASD) for over two decades. These immersive environments create a safe platform in which therapy can address the core symptoms associated with this condition. Recent advancements in spatial audio rendering techniques for VR now allow for the creation of realistic audio environments that accurately match their visual counterparts. However, reported auditory processing impairments associated with autism may affect how an individual interacts with their virtual therapy application. This study aims to investigate if these difficulties in processing audio information would directly impact how individuals with autism interact with a presented virtual spatial audio environment. Two experiments were conducted with participants diagnosed with ASD (n = 29) that compared: (1) behavioral reaction between spatialized and non-spatialized audio; and (2) the effect of background noise on participant interaction. Participants listening to binaural-based spatial audio showed higher spatial attention towards target auditory events. In addition, the amount of competing background audio was reported to influence spatial attention and interaction. These findings suggest that despite associated sensory processing difficulties, those with ASD can correctly decode the auditory cues simulated in current spatial audio rendering techniques