Developmental Effects on Auditory Neural Oscillatory Synchronization Abnormalities in Autism Spectrum Disorder

Area of Science:

• Neuroscience
• Developmental Psychology
• Audiology

Background:

• Previous research indicates altered 40 Hz auditory activity in adults with Autism Spectrum Disorder (ASD).
• The specificity and developmental course of these auditory processing differences require further investigation across age groups.

Purpose of the Study:

• To investigate the specificity and developmental trajectory of auditory oscillatory activity in children and adults with and without ASD.
• To examine neural responses across a range of frequencies to modulated auditory stimuli.

Main Methods:

• Dense-array electroencephalography (EEG) was used on 15 participants with ASD and 15 typically developing (TD) controls (ages 6-25).
• Participants listened to a tone with frequency-modulated amplitude (0-100 Hz).
• EEG data were analyzed for inter-trial phase coherence (ITPC) and single-trial power (STP).

Main Results:

• Older participants with ASD exhibited significantly reduced low gamma phase-locking compared to TD controls.
• Younger ASD and TD participants did not differ significantly in phase-locking.
• An age-by-diagnosis interaction revealed different developmental trajectories for low gamma power: TD showed a decrease with age, while ASD did not.
• Increased low gamma single-trial power in ASD correlated with higher scores for repetitive behaviors, particularly insistence on sameness.

Conclusions:

• Auditory processing, specifically low gamma neural activity, is altered in Autism Spectrum Disorder (ASD).
• Older individuals with ASD demonstrate more significant deficits, indicating an altered developmental trajectory for auditory processing.
• These findings suggest that altered neural activity in ASD may extend beyond auditory processing and relate to core behavioral symptoms.