Reduced orienting to audiovisual synchrony in infancy predicts autism diagnosis at 3 years of age

Background: Effective multisensory processing develops in infancy and is thought to be important for the perception of unified and multimodal objects and events. Previous research suggests impaired multisensory processing in autism, but its role in the early development of the disorder is yet uncertain. Here, using a prospective longitudinal design, we tested whether reduced visual attention to audiovisual synchrony is an infant marker of later-emerging autism diagnosis. Methods: We studied 10-month-old siblings of children with autism using an eye tracking task previously used in studies of preschoolers. The task assessed the effect of manipulations of audiovisual synchrony on viewing patterns while the infants were observing point light displays of biological motion. We analyzed the gaze data recorded in infancy according to diagnostic status at 3 years of age (DSM-5). Results: Ten-month-old infants who later received an autism diagnosis did not orient to audiovisual synchrony expressed within biological motion. In contrast, both infants at low-risk and high-risk siblings without autism at follow-up had a strong preference for this type of information. No group differences were observed in terms of orienting to upright biological motion. Conclusions: This study suggests that reduced orienting to audiovisual synchrony within biological motion is an early sign of autism. The findings support the view that poor multisensory processing could be an important antecedent marker of this neurodevelopmental condition. Keywords: Autism spectrum disorder; infancy; multisensory processing; biological motion; biomarker; scientific replication

Parent-infant interaction in infant siblings at risk of autism

Recent models of the early emergence of autism spectrum disorder (ASD) propose an interaction between risk susceptibility and the infant's social environment, resulting in a progressively atypical developmental trajectory. The infant's early social environmental experience consists mostly of interaction with caregivers, yet there has been little systematic study of early parent-infant interaction in infants at risk of ASD. This study examined the global characteristics of parent-infant interaction in 6- to 10-month-old infants with an older sibling diagnosed with ASD (at-risk sibs), in comparison with a group of infants with no family history of ASD (low-risk sibs). As part of the British Autism Study of Infant Siblings (BASIS), 6-min videotaped unstructured play interactions of mother-infant dyads (45 at-risk sibs and 47 low-risk sibs) were rated on global aspects of parent-infant interaction, blind to participant information. Differences in global characteristics of interaction were observed in both infant and parent contributions in the at-risk group compared to low-risk controls. In analyses adjusted for age and developmental level, at-risk sib infants were less lively, and their parents showed higher directiveness, and lower sensitive responding (as a trend after adjustment). Level of infant liveliness was independent of other interactive behaviour. Consistent with reports in previous literature in older children with autism and in other neurodevelopmental disorders, our findings may suggest that infants at genetic risk are exposed to a more directive interactive style relatively early in infancy. We discuss possible explanations for these findings and implications for further developmental study and intervention. (C) 2012 Elsevier Ltd. All rights reserved.</p

Atypical modulation of face-elicited saccades in autism spectrum disorder in a double-step saccade paradigm

Atypical development of face processing is a major characteristic in autism spectrum disorder (ASD), which could be due to atypical interactions between subcortical and cortical face processing. The current study investigated the saccade planning towards faces in ASD. Seventeen children with ASD and 17 typically developing (TD) children observed a pair of upright or inverted face configurations flashed sequentially in two different spatial positions. The reactive saccades of participants were recorded by eye-tracking. The results did not provide evidence of overall impairment of subcortical route in ASD, However, the upright, but not the inverted, face configuration modulated the frequency of vector sum saccades (an index of subcortical control) in TD, but not in ASD. The current results suggest that children with ASD do not have overall impairment of the subcortical route, but the subcortical route may not be specialized to face processing

Face engagement during infancy predicts later face recognition ability in younger siblings of children with autism

Face recognition difficulties are frequently documented in children with autism spectrum disorders (ASD). It has been hypothesized that these difficulties result from a reduced interest in faces early in life, leading to decreased cortical specialization and atypical development of the neural circuitry for face processing. However, a recent study by our lab demonstrated that infants at increased familial risk for ASD, irrespective of their diagnostic status at 3 years, exhibit a clear orienting response to faces. The present study was conducted as a follow-up on the same cohort to investigate how measures of early engagement with faces relate to face-processing abilities later in life. We also investigated whether face recognition difficulties are specifically related to an ASD diagnosis, or whether they are present at a higher rate in all those at familial risk. At 3 years we found a reduced ability to recognize unfamiliar faces in the high-risk group that was not specific to those children who received an ASD diagnosis, consistent with face recognition difficulties being an endophenotype of the disorder. Furthermore, we found that longer looking at faces at 7 months was associated with poorer performance on the face recognition task at 3 years in the high- risk group. These findings suggest that longer looking at faces in infants at risk for ASD might reflect early face-processing difficulties and predicts difficulties with recognizing faces later in life

Neurocognitive and observational markers: prediction of autism spectrum disorder from infancy to mid-childhood

Background Prospective studies of infants at high familial risk for autism spectrum disorder (ASD) have identified a number of putative early markers that are associated with ASD outcome at 3 years of age. However, some diagnostic changes occur between toddlerhood and mid-childhood, which raises the question of whether infant markers remain associated with diagnosis into mid-childhood. Methods First, we tested whether infant neurocognitive markers (7-month neural response to eye gaze shifts and 14-month visual disengagement latencies) as well as an observational marker of emerging ASD behaviours (the Autism Observation Scale for Infants; AOSI) predicted ASD outcome in high-risk (HR) 7-year-olds with and without an ASD diagnosis (HR-ASD and HR-No ASD) and low risk (LR) controls. Second, we tested whether the neurocognitive markers offer predictive power over and above the AOSI. Results Both neurocognitive markers distinguished children with an ASD diagnosis at 7 years of age from those in the HR-No ASD and LR groups. Exploratory analysis suggested that neurocognitive markers may further differentiate stable versus lost/late diagnosis across the 3 to 7 year period, which will need to be tested in larger samples. At both 7 and 14 months, combining the neurocognitive marker with the AOSI offered a significantly improved model fit over the AOSI alone. Conclusions Infant neurocognitive markers relate to ASD in mid-childhood, improving predictive power over and above an early observational marker. The findings have implications for understanding the neurodevelopmental mechanisms that lead from risk to disorder and for identification of potential targets of pre-emptive intervention

Diminished socially selective neural processing in 5-month-old infants at high familial risk of autism

The social and communicative difficulties that characterize autism spectrum disorder (ASD) are considered the most striking fea-ture of the disorder. Research has reported that individuals with ASD show abnormalities in the brain regions associated with theprocessing of social information. Importantly, a recent study using functional near-infrared spectroscopy (fNIRS) found the firstevidence of atypicalities in the neural processing of social information in 4- to 6-month-old infants at high familial risk of ASD.These findings provide an important step in the search for early markers of ASD and highlight the potential for neuroimaging tech-niques to detect atypical patterns of neural activity prior to the manifestation of most behavioural symptoms. This study aimed toextend the findings of reduced neural sensitivity to social stimuli in an independent cohort. Twenty-nine 5-month-old infants (13low-risk infants, 16 high-risk infants) were presented with social and non-social visual stimuli, similar to the previous experiment.Importantly, a non-social dynamic motion control condition was introduced allowing the comparison between social dynamic andnon-social, static, as well as dynamic stimuli. We found that while low-risk infants showed activation to social stimuli in the rightposterior temporal cortex, this activation was reduced in infants at high risk of ASD. Although the current sample size was rela-tively small, our results replicate and extend previous work and provide evidence for a social processing difference in infants atrisk of autism. Future research will determine whether these differences relate to an eventual ASD diagnosis or may rather reflectthe broader autism phenotype

Functional near infrared spectroscopy (fNIRS) to assess cognitive function in infants in rural Africa

Cortical mapping of cognitive function during infancy is poorly understood in low-income countries due to the lack of transportable neuroimaging methods. We have successfully piloted functional near infrared spectroscopy (fNIRS) as a neuroimaging tool in rural Gambia. Four-to-eight month old infants watched videos of Gambian adults perform social movements, while haemodynamic responses were recorded using fNIRS. We found distinct regions of the posterior superior temporal and inferior frontal cortex that evidenced either visual-social activation or vocally selective activation (vocal > non-vocal). The patterns of selective cortical activation in Gambian infants replicated those observed within similar aged infants in the UK. These are the first reported data on the measurement of localized functional brain activity in young infants in Africa and demonstrate the potential that fNIRS offers for field-based neuroimaging research of cognitive function in resource-poor rural communities

Global prevalence of autism and other pervasive developmental disorders

We provide a systematic review of epidemiological surveys of autistic disorder and pervasive developmental disorders (PDDs) worldwide. A secondary aim was to consider the possible impact of geographic, cultural/ethnic, and socioeconomic factors on prevalence estimates and on clinical presentation of PDD. Based on the evidence reviewed, the median of prevalence estimates of autism spectrum disorders was 62/10 000. While existing estimates are variable, the evidence reviewed does not support differences in PDD prevalence by geographic region nor of a strong impact of ethnic/cultural or socioeconomic factors. However, power to detect such effects is seriously limited in existing data sets, particularly in low-income countries. While it is clear that prevalence estimates have increased over time and these vary in different neighboring and distant regions, these findings most likely represent broadening of the diagnostic concets, diagnostic switching from other developmental disabilities to PDD, service availability, and awareness of autistic spectrum disorders in both the lay and professional public. The lack of evidence from the majority of the world's population suggests a critical need for further research and capacity building in low- and middle-income countries

The eye contact effect: mechanisms and development

The ‘eye contact effect’ is the phenomenon that perceived eye contact with another human face modulates certain aspects of the concurrent and/or immediately following cognitive processing. In addition, functional imaging studies in adults have revealed that eye contact can modulate activity in structures in the social brain network, and developmental studies show evidence for preferential orienting towards, and processing of, faces with direct gaze from early in life. We review different theories of the eye contact effect and advance a ‘fast-track modulator’ model. Specifically, we hypothesize that perceived eye contact is initially detected by a subcortical route, which then modulates the activation of the social brain as it processes the accompanying detailed sensory information