Aliehs Lee

Background: Autism spectrum disorder (ASD) is a complex neurological condition marked by deficits in executive functioning, motor repetitions, and social interaction⁴. While the etiology of autism spectrum disorder remains unclear, research into potential biomarkers holds promise for improving early diagnosis and intervention^3,4. The primary therapeutic approach for ASD currently involves a combination of cognitive and behavioral therapies. Early intervention is crucial for optimizing outcomes in children with ASD, particularly in addressing cognitive and social deficits⁴. Neurophysiological abnormalities, including mu rhythm slowing, correlate with decreased motor performance in ASD individuals⁶. Previous studies have linked ASD with EEG patterns, especially mu rhythm in the alpha frequency range, associated with various cognitive functions⁶. Alterations in mu rhythm activity has been linked to sensorimotor processing irregularities and social communication challenges in ASD, suggesting its potential as a biomarker for understanding motor skills in ASD⁶.

Objective: This narrative review explores EEG mu rhythm patterns as potential biomarkers for understanding motor skill mechanisms in individuals with ASD.

Search Methods: An online search in the PubMed database from 2018 to 2023 using keywords including “autism spectrum disorder”, “brain waves”, “electroencephalography”, “mu rhythm”, “EEG alpha rhythm”, and “motor activity”.

Results: Studies indicate that participants with ASD display reduced coordination and precision of movement compared to neurotypical controls, suggesting differences in speech production and fine motor skills⁷. Speech and handwriting tasks effectively distinguish between ASD and control participants, demonstrating their potential as ASD biomarkers⁷. Electrophysiological analysis reveal decreased neural synchronization with visual cues in the ASD group, despite intact visual responses, and preserved behavioral temporal prediction following cues². In addition, test-retest reliability of EEG power spectral density profiles was higher in typical developing participants than ASD, suggesting greater neural activity variability in ASD⁵. Collectively, these findings advance understanding of EEG power spectral density reliability for future ASD diagnostic biomarkers^2,5. Modifications in mu rhythm activity are associated with sensorimotor processing irregularities and social communication challenges in ASD individuals¹. Higher autism spectrum traits in the neurotypical sample are associated with mu rhythm slowing⁶. However, further validation through larger studies is needed due to EEG modality limitations in children and clinical populations^1,6.

Conclusion: Ongoing research indicates abnormalities in mu rhythm activity and connectivity, influencing neural mechanisms underlying social and motor challenges in ASD. These studies offer insight into EEG mu rhythm and its association with fine motor control mechanisms, potentially advancing understanding of ASD biomarkers. Yet, further research with larger, diverse samples is necessary to understand how mu rhythm frequencies correlate with autism spectrum traits.

Work Cited:

1. Aaronson B, Estes A, Rogers SJ, Dawson G, Bernier R. The Early Start Denver Model Intervention and Mu Rhythm Attenuation in Autism Spectrum Disorders. J Autism Dev Disord. 2022;52(7):3304-3313. doi:10.1007/s10803-021-05190-7
2. Beker S, Foxe JJ, Molholm S. Oscillatory entrainment mechanisms and anticipatory predictive processes in children with autism spectrum disorder. J Neurophysiol. 2021;126(5):1783-1798. doi:10.1152/jn.00329.2021
3. Frye RE, Vassall S, Kaur G, Lewis C, Karim M, Rossignol D. Emerging biomarkers in autism spectrum disorder: a systematic review. Ann Transl Med. 2019;7(23):792. doi:10.21037/atm.2019.11.53
4. Klin A. Frontiers in the research of autism pathogenesis. Fronteras en la investigación de la patogenia del autismo. Medicina (B Aires). 2022;82 Suppl 1:33-36.
5. Levin AR, Naples AJ, Scheffler AW, et al. Day-to-Day Test-Retest Reliability of EEG Profiles in Children With Autism Spectrum Disorder and Typical Development. Front Integr Neurosci. 2020;14:21. Published 2020 Apr 30. doi:10.3389/fnint.2020.00021
6. Strang CC, Harris A, Moody EJ, Reed CL. Peak frequency of the sensorimotor mu rhythm varies with autism-spectrum traits. Front Neurosci. 2022;16:950539. Published 2022 Aug 5. doi:10.3389/fnins.2022.950539
7. Talkar T, Williamson JR, Hannon D, et al. Assessment of speech and fine motor coordination in children with autism spectrum disorder. IEEE Access. 2020;8:127535-127545. doi:10.1109/ACCESS.2020.3007348