Brain Signatures of Early and Late Neural Measures of Auditory Habituation and Discrimination in Autism and Their Relationship to Autistic Traits and Sensory Overresponsivity.

Sensory differences are included in the DSM-5 criteria of autism for the first time, yet it is unclear how they relate to neural indicators of perception. We studied early brain signatures of perception and examined their relationship to sensory behaviors and autistic traits. Thirteen autistic children and 13 Typically Developing (TD) children matched on age and nonverbal IQ participated in a passive oddball task, during which P1 habituation and P1 and MMN discrimination were evoked by pure tones. Autistic children had less neural habituation than the TD comparison group, and the MMN, but not P1, mapped on to sensory overresponsivity. Findings highlight the significance of temporal and contextual factors in neural information processing as it relates to autistic traits and sensory behaviors.

Barriers to an Autistic Identity: How RRBs may Contribute to the Underdiagnosis of Females.

Background: Autistic females are frequently underdiagnosed, misdiagnosed, and/or diagnosed later in life. Restricted and Repetitive Behaviors (RRBs) are increasingly critical for diagnosis and yet are commonly rated lower in females. Whether this reflects genuinely lower levels of these traits, or if female-typical RRBs have a different phenotypic presentation that may not register on current quantitative measurement tools is unclear. Methods: Twenty-one autistic females and 21 autistic males matched on chronological age and FSIQ completed the AQ, ADOS-2, and ADI-R. Items from the ADOS-2 and ADI-R were selected that were relevant to the four areas of restricted and repetitive behavior in the DSM-5 diagnostic criteria of autism. Using a mixed-methods analytical approach, scores and comments on these measures were compared between sexes to better characterize RRBs in autistic females. Results: There were no sex differences on the AQ, which broadly assesses autistic traits. When analyzed by the four DSM-5 RRB criteria, there were no sex differences on the ADI-R when using traditional algorithm scoring that narrows questions down to those that are more sensitive and specific in capturing autism in research samples with a high proportion of males. When incorporating additional items relevant to the DSM-5 to identify sex changes in a broader pool of items, females scored higher on stereotyped movements and speech. Females also engaged in more sensory behaviors during the ADOS-2. Qualitative analyses indicated that females were more likely to engage in stereotyped body rocking and spinning, stereotyped behaviors when anxious, to show major reactions to changes, repetitive language including listing and counting, and sensory behaviors, especially in the tactile domain. Conclusion: Exploratory findings highlight sex differences in RRBs that may help enhance diagnostic clarity for females. Higher tactile sensory behaviors in females suggests there may be increased diagnostic sensitivity for females with the updated DSM-5 that now includes sensory components as part of the diagnostic criteria.

A Preliminary Study Characterizing Subcortical and Cortical Auditory Processing and Their Relation to Autistic Traits and Sensory Features.

This study characterizes the subcortical auditory brainstem response (speech-ABR) and cortical auditory processing (P1 and Mismatch Negativity; MMN) to speech sounds and their relationship to autistic traits and sensory features within the same group of autistic children (n = 10) matched on age and non-verbal IQ to their typically developing (TD) peers (n = 21). No speech-ABR differences were noted, but autistic individuals had larger P1 and faster MMN responses. Correlations revealed that larger P1 amplitudes and MMN responses were associated with greater autistic traits and more sensory features. These findings highlight the complexity of the auditory system and its relationships to behaviours in autism, while also emphasizing the importance of measurement and developmental matching.