Abstract
Objective
We aim to determine whether automatically detected ripple rate (ADRR) of ten-minute scalp electroencephalography (EEG) during slow-wave sleep can be a useful tool for rapid epilepsy differentiation and seizure activity assessment, and analyze the clinical factors that may affect it.
Methods
We retrospectively included 336 patients who underwent long-term video EEG with a sampling rate ≥1000 Hz, and three groups were established based on their final clinical diagnosis (non-epilepsy; non-active epilepsy [epilepsy being seizure free for at least one year]; and active epilepsy [epilepsy with one or more seizures in the past year]). ADRRs between groups were compared and diagnostic thresholds set according to the maximum of Youden Index with receiver operating characteristic curve.
Results
The 336 patients comprised 49 non-epilepsy and 287 epilepsy patients (95 non-active epilepsy and 192 active epilepsy). The median ADRR of the epilepsy group was significantly greater than in the non-epilepsy group, with a diagnostic threshold of 4.25 /min (specificity 89.8%, sensitivity 47.74%, p<0.001). Following stratification by age, the area under the curve was greatest in the 0–20 years subgroup, threshold 4.10 /min (specificity 100%, sensitivity 52.47%, p<0.001). Regarding distinguishing active epilepsy from non-active epilepsy patients, the area under the curve was also greatest in patients aged 0–20 years, threshold 13.05 /min (specificity 98.36%, sensitivity 35.64%, p<0.001). Following stratification by epilepsy type, the diagnostic efficiency was best in children with developmental and epileptic encephalopathies / epileptic encephalopathies (DEEs/EEs) (threshold 5.20 /min, specificity 100%, sensitivity 100%) and self-limited focal epilepsies (SeLFEs) (threshold 5.45 /min, specificity 80%, sensitivity 100%). Multivariate analysis revealed that the influential factors of ADRRs were age, depth of epileptogenic lesion and seizure frequency.
Significance
ADRR of scalp EEG can be a rapid and specific method to differentiate epilepsy and evaluate seizure activity. This method is especially suitable for young patients.
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