Monitoring seizure cycles with seizure diaries

Abstract

Objective: The periodicity of seizures, ranging from circadian to circannual cycles, is increasingly recognized as a significant opportunity to advance epilepsy management. Current methods for detecting seizure cycles rely on intrusive techniques or specialised biomarkers, limiting their accessibility. This study evaluates a non-invasive seizure cycle detection method using seizure diaries and compares its accuracy with cycles identified from intracranial electroencephalography (iEEG) seizures and interictal epileptiform discharges (IEDs). Approach: Using data from a previously published first in-human iEEG device trial (n=10), we analysed seizure cycles identified through diary reports, iEEG seizures and IEDs. Cycle similarities across diary reports, iEEG seizures and iEDs were evaluated at periods of 1 to 45 days using spectral coherence, accuracy, precision and recall scores. Main results: Spectral coherence of the raw signals averaged over frequencies and participants indicated moderately similar frequency components between diary seizures/day and iEEG seizures/day (Median=0.43, IQR=0.68). In contrast, there was low coherence between diary seizures/day and IEDs/day (Median=0.11, IQR=0.18) and iEEG seizures/day and IEDs/day (Median=0.12, IQR=0.19). Mean accuracy, precision and recall of iEEG seizure cycles from diary seizure cycles was significantly higher than chance across all participants (Accuracy: Mean=0.95, SD=0.02; Precision: Mean=0.56, SD=0.19; Recall: Mean=0.56, SD=0.19). Accuracy, precision and recall scores between seizures cycles using diary or iEEG compared to IED cycles did not perform above chance, on average. Recall scores were compared across good diary reporters, under-reporters and over-reporters, with recall scores generally performing better in good reporters and under-reporters (Mean=0.74, SD=0.02) compared to over-reporters (Mean=0.37, SD=0.06). Significance: These findings suggest that iEEG seizure cycles can be identified with diary reports, even in both under- and over-reporters. This approach offers a practical, accessible alternative for monitoring seizure cycles compared to more invasive methods.