32414
Event-Related Brain Dynamics of Auditory Cognitive Control in Adults with Autism Spectrum Disorder
Atypical sensory reactivity in autism spectrum disorder (ASD) is a core diagnostic feature. It is also one of the earliest and most persistent indicators to be behaviorally observed in this clinical population. Yet, a basic understanding of the neural mechanisms that mediate these behaviors remains unclear. Event-related neural oscillatory activity plays a key role in brain function and is easily evaluated by electroencephalography (EEG), which provides a high-temporal resolution of brain dynamics. Specifically, theta- (4-8 Hz), alpha- (8–12 Hz), and gamma-band (25-50 Hz) activity, are important for sensory processing, sensory integration, and working memory. Additionally, these bands have been observed as atypical in ASD and have been associated with deficits in cortical inhibition. In neurotypical controls, event-related spectral dynamics associated with target detection in the oddball paradigm have been used to examine the functional integrity of brain circuits. However, this relationship has not been well-characterized among adults with ASD.
Objectives:
In participants with ASD and age- and IQ-matched neurotypical controls, event-related spectral dynamics during attentional processing in an auditory oddball task will be evaluated. The relationship between sensory reactivity and average band power will also be examined.
Methods:
Adults with ASD (N=12) and age- and IQ-matched control controls (N=12) completed a modified 3-stimulus (target, non-target, and distractor) oddball task, as well as being assessed by the Adolescent/Adult Sensory Profile (AASP) and Kaufman Brief Intelligence Test (KBIT-2). During the oddball task, scalp-level EEG was recorded as the stimuli was binaurally presented, this included: randomly infrequent pure tone targets (1000 Hz, probability = .12) presented at 0° midline and frequent non-targets/distractors (probability = .88) with an inter-stimulus interval of 2000ms (~60dB, 200ms duration, 200 stimuli/block, 8 blocks total). EEG data was filtered, segmented into 2-s epochs, and edited for artifacts. Time/frequency analysis was performed using the standard frequency band ranges: Delta: 1- 4 Hz; Theta: 4 - 8 Hz, Alpha: 8 - 12 Hz; Beta: 12 - 25 Hz; Gamma: 25 - 50 Hz; and High Gamma: 50 - 80Hz. A 2x5 ANOVA (threshold p<.05) was used to compare power spectra across bands and between groups.
Results:
Average power at low perceptual loads were significantly different between groups (p=0.015). Adults with ASD demonstrated decreased theta and alpha-band power as well as increased gamma-band power (p=0.0127, p=0.06, p=0.044). Changes in spectral power in those with ASD were correlated with atypical reactivity (r=0.851).
Conclusions:
In adults with ASD increased sensory reactivity were related to changes in spectral power in low-and high-frequency bands compared to neurotypical controls. This atypical EEG pattern in auditory target detection is a potentially distinct profile of neural circuits functionality in sensory processing and top-down cognitive control between in adults with ASD.