Application Of Scalp-recorded High Frequency Oscillations In Infantile Spasms

Objective:To investigate the clinical significance of high-frequency oscillations(HFOs)on scalp electroencephalography(EEG)in patients with infantile spasms(IS).Methods: A prospective study of 27 children with IS admitted to Children's Hospital of Chongqing Medical University from January to November 2019 were collected,and 54 normal children of the same age were used as the control group.The power changes of gamma oscillation,ripple oscillation and fast ripple oscillation before and after treatment were quantitatively analyzed by time-frequency analysis.Results:(1)The electroencephalogram(EEG)of the scalp of IS and normal children can record three frequency bands,including gamma oscillation,ripple oscillation and fast ripple oscillation.The sites of IS and normal children were mainly temporal lobe and frontal lobe;(2)The mean power of gamma oscillation in normal children during waking period was significantly higher than that in normal sleeping period(P < 0.01).The average power of no discharge during waking period,discharge duringwaking period was significantly higher than that in the normal waking period(P<0.01).However,there was no significant difference in the mean power of gamma oscillations between the waking discharges period and the sleeping discharges period compared with the non-discharges in the waking period.The mean power of gamma oscillation during the ictal period was significantly higher than that of normal waking period(P < 0.01);(3)The average power of ripple and fast ripple oscillations and gamma oscillations in the normal group had similar changing trends.For children with IS,the average power of the ripple and fast ripple oscillations changed irregularly during the Interictal period and the onset period;(4)The EEG of 14 children were reviewed after 4 weeks,and were divided into effective group and ineffective group according to the clinical efficacy and EEG score of 4weeks,among which 9 were effective group and 5 were ineffective group.There was no significant difference in scalp BASED EEG scores between the effective group and the non-effective group before treatment(P > 0.05).(5).The average power of ripple oscillation and the fast ripple oscillation also have similar change trend.The average power of no discharge in awake period of the ineffective group in fast ripple oscillation is higher than that of the effective group in the same period(P < 0.05).(6)The BASED score of EEG before treatment was higher than that after treatment(P < 0.01).The average power of each stage before treatment was higherthan that of the same stage after treatment,but the difference was not statistically significant(P > 0.05).The average power of ripple oscillation and the average power of fast ripple oscillation also had similar change trend(P > 0.05).Conclusion:(1)Scalp EEG can record HFOs.The frequency of HFOs is not necessary to distinguish between physiological and pathological states.Physiological HFOs and pathological HFOs may have different sleep balance characteristics.(2)Compared with ripple and FRS,Gamma oscillation of the scalp EEG can reflect the severity of epilepsy,and can be used to evaluate the therapeutic effect of epilepsy.(3)Scalp electroencephalogram HFOs can help to detect the susceptibility of epilepsy and predict the onset of epilepsy.