Poster C114, Sunday, March 26, 5:00 – 7:00 pm, Pacific Concourse
Differential altered auditory electrocortical responses in young children with and without megalencephaly on the autism spectrum.
Rosanna De Meo1,2, Sevan K. Haroontonian1, Christine Wu Nordahl2, David G. Amaral2, Susan M. Rivera1,2,3, Clifford Saron1,2; 1Center for Mind and Brain, University of California at Davis, Davis, CA, 2MIND Institute, University of California at Davis School of Medicine, Sacramento, CA, 3Department of Psychology, University of California at Davis, Davis, CA
Autism spectrum disorder (ASD), characterized by impairments in social communication and repetitive behavior, also includes unusual responses to sensory input as part of its phenotype. The large heterogeneity within ASD is a challenge for understanding its biological basis. This study, part of a larger multi-disciplinary effort to identify autism subphenotypes, investigated the relation between neuroanatomical differences, based on structural MRI, and electrocortical responses to auditory stimuli of increasing loudness in young (26-46 mos.) typically developing (TD) boys and those with ASD. 61-channel ERPs were elicited by randomly interleaved 50, 60, 70, and 80 dB 50-ms tones (ISI 1-2s, ~300 stim/condition). Analyses included data from 33 age-matched boys, of which 22 were diagnosed with ASD (including 11 with, and 11 without, disproportionate megalencephaly) and 11 were TD children. Significant differences in the scalp-surface global power of the electric field evoked by the different intensities were only found in the TD children (130-160 ms and 410-440 ms post-stimulus). Periods of topographical modulations, and by extension, configuration of intracranial generators, were found between the two ASD groups, as well as with the TD group at most intensities. These results suggest graded, loudness dependent, auditory responses only in TD children. While both ASD groups appear to lack these intensity-related modulations, the ASD groups do differ in the configuration of brain generators involved, suggesting an impact of brain morphometry on auditory processing within the ASD group. These data contribute to the effort to delineate ASD subgroups and further characterize physiological mechanisms underlying observable phenotypes.
Topic Area: PERCEPTION & ACTION: Audition