A study on the relationship between non-epileptic fast (40 – 200 Hz) oscillations in scalp EEG and development in children

Abstract

ObjectivePhysiological gamma and ripple activities may be linked to neurocognitive functions. This study investigated the relationship between development and non-epileptic, probably physiological, fast (40–200 Hz) oscillations (FOs) including gamma (40 – 80 Hz) and ripple (80 – 200 Hz) oscillations in scalp EEG in children with neurodevelopmental disorders. MethodsParticipants were 124 children with autism spectrum disorder (ASD) and/or attention deficit/hyperactivity disorder (ADHD). Gamma and ripple oscillations were explored from 60-second-long sleep EEG data in each subject using a semi-automatic detection tool supplemented with visual confirmation and time–frequency analysis. ResultsGamma and ripple oscillations were detected in 25 (20.2%) and 22 (17.7%) children, respectively. The observation of one or more occurrence(s) of ripple oscillations, but not gamma oscillations, was significantly related to lower age at EEG recording (odds ratio, OR: 0.727 [95% confidence interval, CI: 0.568–0.929]), higher intelligence/developmental quotient (OR: 1.041, 95% CI: 1.002–1.082), and lack of a diagnosis with ADHD (OR: 0.191, 95% CI: 0.039 – 0.937) according to a binominal logistic regression analysis that included diagnosis with ASD, sex, history of perinatal complications, history of febrile seizures, and use of a sedative agent for the EEG recording as the other non-significant parameters. Diagnostic group was not related to frequency or power of spectral peaks of FOs. ConclusionThe production of non-epileptic scalp ripples was confirmed to be associated with brain development and function/dysfunction in childhood. Further investigation is necessary to interpret all of the information on higher brain functions that may be embedded in scalp FOs.