Abnormal auditory mismatch fields in adults with autism spectrum disorder

Area of Science:

• Neuroscience
• Auditory Processing
• Autism Spectrum Disorder Research

Background:

• Auditory mismatch fields (MMF) are crucial for pre-attentive auditory discrimination and inhibitory processing.
• Previous studies noted MMF abnormalities in children with ASD, linked to language comprehension deficits.
• Limited research exists on MMF responses to vowel stimuli in adults with ASD.

Purpose of the Study:

• To investigate neurophysiological mechanisms of auditory language discrimination in adults with ASD.
• To measure MMFs to contrasting vowel stimuli using magnetoencephalography (MEG).
• To compare MMFs between adults with ASD and typically developing (TD) individuals.

Main Methods:

• Magnetoencephalography (MEG) was employed to record MMFs.
• An auditory oddball paradigm with /a/ and /u/ vowel stimuli was used.
• Participants included nine high-functioning right-handed males with ASD and sixteen TD right-handed males.

Main Results:

• Adults with ASD exhibited delayed MMF latency (188.90 ms) compared to TD participants (173.08 ms).
• An earlier component, M100, was also delayed in adults with ASD (108.59 ms) versus TD participants (94.60 ms).
• TD participants showed leftward MMF amplitude lateralization, while ASD participants displayed rightward lateralization.

Conclusions:

• Adults with ASD demonstrate temporally abnormal auditory discrimination processing.
• Hemispheric differences in MMF amplitude lateralization suggest altered brain organization in ASD.
• These auditory processing abnormalities are distinct from earlier cortical response mechanisms in ASD.