High-frequency oscillations in idiopathic partial epilepsy of childhood
Katsuhiro Kobayashi1, Harumi Yoshinaga, Yoshihiro Toda
1Department of Child Neurology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences and Okayama University Hospital, Okayama, Japan. k_koba@md.okayama-u.ac.jp
Insights
High-frequency oscillations (HFOs) detected in pediatric epilepsy EEG are linked to active seizure periods. These HFOs may offer deeper insights into epileptogenicity and potentially indicate a poorer prognosis in childhood epilepsy.
Area of Science:
- Neurology
- Pediatric Neurology
- Epileptology
Background:
- Idiopathic partial epilepsy (IPE) of childhood presents diagnostic challenges.
- Understanding the underlying pathologic mechanisms of IPE is crucial for effective management.
- Scalp sleep electroencephalography (EEG) is a key tool in epilepsy diagnosis.
Purpose of the Study:
- To explore high-frequency oscillations (HFOs) in sleep EEG of children with IPE.
- To enhance understanding of the pathologic mechanisms contributing to IPE.
- To investigate the relationship between HFOs, spikes, and seizure activity.
Main Methods:
- Analysis of 136 EEG records from 45 pediatric patients with IPE (32 with benign childhood epilepsy with centrotemporal spikes [BCECTS], 13 with Panayiotopoulos syndrome [PS]).
- Utilized temporal expansion, trace filtering, and time-frequency spectral analysis to detect HFOs.
- Investigated the association of HFOs with spikes and their correlation with seizure occurrence and patient age.
Main Results:
- HFOs (93.8–152.3 Hz) were detected in 71.3% of records, often associated with spikes.
- Spike-related HFOs were significantly more common when EEG recordings were closer to the last seizure (p = 0.006).
- Peak power of HFOs negatively correlated with time from last seizure (R(2) = 0.122, p < 0.001), but not with age.
Conclusions:
- Spike-related HFOs are closely linked to active seizure periods in IPE, suggesting they may reflect epileptogenicity more than spikes alone.
- The prominence of HFOs in IPE compared to more severe conditions like epilepsy with continuous spike-waves during slow-wave sleep (CSWS) suggests a potential prognostic value.
- Intense spike-related HFOs might indicate a poorer prognosis in pediatric epilepsy, especially when considering the spectrum from BCECTS to CSWS.
Purpose:
We explored high-frequency oscillations (HFOs) in scalp sleep electroencephalography (EEG) studies of patients with idiopathic partial epilepsy (IPE) of childhood in order to obtain a better understanding of the pathologic mechanisms underlying IPE.
Methods:
The subjects were 45 patients, including 32 with benign childhood epilepsy with centrotemporal spikes (BCECTS) and 13 with Panayiotopoulos syndrome (PS). A total of 136 EEG records were investigated through temporal expansion and filtering of traces and time-frequency spectral analysis.
Key Findings:
HFOs with frequency of 93.8-152.3 Hz (mean 126.2 ± 13.6 Hz) in the band of ripples were detected in association with spikes in 97 records (71.3%). Time from last seizure to the EEG recording was significantly shorter in those with spike-related HFOs than in the EEG recordings with spikes without HFOs (p = 0.006). Although time from last seizure reflects age, age at the time of recording was not significantly different between EEG studies with and without HFOs. Peak-power values of the high-frequency spots in time-frequency spectra were significantly negatively correlated with time from last seizure (R(2) = 0.122, p < 0.001) but not with age at the time of recording. Peak frequencies of the high-frequency spectral spots were not significantly correlated with age at the time of recording or with time from last seizure.
Significance:
The close relationship between the generation of spike-related HFOs and the period of active seizure occurrence indicated that HFOs may tell us more about epileptogenicity in IPE than the spikes themselves. Because there is a spectrum of pediatric epileptic disorders extending from the benign end of BCECTS to the encephalopathic end of epilepsy with continuous spike-waves during slow-wave sleep (CSWS), and HFOs that have already been detected in association with CSWS were more prominent than HFOs in IPE, intense spike-related HFOs may indicate poor prognosis.
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