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Thursday, May 7, 2009
Northwest Hall (Chicago Hilton)
12:00 PM
Background:
One of the most exciting and rapidly evolving areas of research on ASD is the identification of risk markers that can be identified in the infancy period. Zwaigenbaum et al. provide the rationale for employing prospective longitudinal designs of infants at risk (basis of an older diagnosed sibling), an approach that is now being followed by a growing number of research groups. At 9-10 months, differences between high and low risk infants were found in visual disengagement, and in response to direct and averted eye gaze (Elsabbagh et al., in press a, b) using eye-tracking and ERP measures.
Objectives:
We are investigating differences in neurobehavioral markers of risk in visual processing systems that can be detected between 6 and 12 months. This is a highly significant developmental stage because during this time development of both language and social perception depend on critical socially-embedded learning experiences. Our research program focuses on identifying neurobehavioral indices of social attention as well as general measures of cognitive and brain development using a combination of behavioral, eye-tracking and neurophysiological (EEG; ERP) measures.
Methods:
In the current project we employ high-density event-related potentials (ERPs) and eye tracking to examine risk-markers for ASD among infants at high risk for autism (HRA) (by virtue of having one affected sibling). Infants are being studied at 6, 9 and 12 months. Using ERPs and eye tracking, we are examining the processing of mother vs. stranger.
Results:
On the ERP data we have collected to date we conducted statistical analyses. At 6 months, the peak amplitude for the N290 yielded a significant group x region interaction; similar findings were obtained for the mean amplitude. We also analyzed the Nc and at 6 months there was a significant group x person interaction for latency: the low risk group latencies were shorter to the mother, whereas the HRA group latencies were shorter to the stranger; latencies for this group were overall, longer. Behaviorally, the infants with preliminary diagnostic outcomes of ASD look proportionately less at their mothers at both 6 and 9 months. No significant effects were found at 12 months. The second figure shows the proportion of time looking at the eyes at 6, 9, and 12 months. The infants with ASD preliminary outcomes show a sharp decline in time spent looking at the eyes between 9 and 12 months. Reduced attention to the eyes in the HRA infants is consistent with findings from other labs.
Conclusions:
These data suggest that there are interesting group differences at 6 months in brain regions processing, and in neural markers of attention to familiar and unfamiliar faces. We speculate that the absence of group effects at 12 months may be the result of increased heterogeneity in the neurophysiology of face processing in the HRA infants.
One of the most exciting and rapidly evolving areas of research on ASD is the identification of risk markers that can be identified in the infancy period. Zwaigenbaum et al. provide the rationale for employing prospective longitudinal designs of infants at risk (basis of an older diagnosed sibling), an approach that is now being followed by a growing number of research groups. At 9-10 months, differences between high and low risk infants were found in visual disengagement, and in response to direct and averted eye gaze (Elsabbagh et al., in press a, b) using eye-tracking and ERP measures.
Objectives:
We are investigating differences in neurobehavioral markers of risk in visual processing systems that can be detected between 6 and 12 months. This is a highly significant developmental stage because during this time development of both language and social perception depend on critical socially-embedded learning experiences. Our research program focuses on identifying neurobehavioral indices of social attention as well as general measures of cognitive and brain development using a combination of behavioral, eye-tracking and neurophysiological (EEG; ERP) measures.
Methods:
In the current project we employ high-density event-related potentials (ERPs) and eye tracking to examine risk-markers for ASD among infants at high risk for autism (HRA) (by virtue of having one affected sibling). Infants are being studied at 6, 9 and 12 months. Using ERPs and eye tracking, we are examining the processing of mother vs. stranger.
Results:
On the ERP data we have collected to date we conducted statistical analyses. At 6 months, the peak amplitude for the N290 yielded a significant group x region interaction; similar findings were obtained for the mean amplitude. We also analyzed the Nc and at 6 months there was a significant group x person interaction for latency: the low risk group latencies were shorter to the mother, whereas the HRA group latencies were shorter to the stranger; latencies for this group were overall, longer. Behaviorally, the infants with preliminary diagnostic outcomes of ASD look proportionately less at their mothers at both 6 and 9 months. No significant effects were found at 12 months. The second figure shows the proportion of time looking at the eyes at 6, 9, and 12 months. The infants with ASD preliminary outcomes show a sharp decline in time spent looking at the eyes between 9 and 12 months. Reduced attention to the eyes in the HRA infants is consistent with findings from other labs.
Conclusions:
These data suggest that there are interesting group differences at 6 months in brain regions processing, and in neural markers of attention to familiar and unfamiliar faces. We speculate that the absence of group effects at 12 months may be the result of increased heterogeneity in the neurophysiology of face processing in the HRA infants.