Seizure-related differences in biosignal 24-h modulation patterns

Abstract

A seizure likelihood biomarker could improve seizure monitoring and facilitate adjustment of treatments based on seizure risk. Here, we tested differences in patient-specific 24-h-modulation patterns of electrodermal activity (EDA), peripheral body temperature (TEMP), and heart rate (HR) between patients with and without seizures. We enrolled patients who underwent continuous video-EEG monitoring at Boston Children's Hospital to wear a biosensor. We divided patients into two groups: those with no seizures and those with at least one seizure during the recording period. We assessed the 24-h modulation level and amplitude of EDA, TEMP, and HR. We performed machine learning including physiological and clinical variables. Subsequently, we determined classifier performance by cross-validated machine learning. Patients with seizures (n = 49) had lower EDA levels (p = 0.031), EDA amplitudes (p = 0.045), and trended toward lower HR levels (p = 0.060) compared to patients without seizures (n = 68). Averaged cross-validated classification accuracy was 69% (AUC-ROC: 0.75). Our results show the potential to monitor and forecast risk for epileptic seizures based on changes in 24-h patterns in wearable recordings in combination with clinical variables. Such biomarkers might be applicable to inform care, such as treatment or seizure injury risk during specific periods, scheduling diagnostic tests, such as admission to the epilepsy monitoring unit, and potentially other neurological and chronic conditions.

Figure 1

Individual recordings of EDA, TEMP, HR (from top to bottom) averaged over 10-min segments of no-seizure (teal left panel) and seizure patients (purple middle panel) are displayed over 24 h. The right panel shows the mean curves of respective autonomic modalities for no-seizure (green) and seizure (purple) patient groups.

Figure 2

Schematic illustration of data collection and analysis steps, including (from left to right) recording with the wearable wristband, raw data processing, averaging of data over 10-min-segments, 24-h pattern modulation modeling (cycle start: 2 pm), amplitude and level calculation, adding clinical variables, and classification into a seizure or a non-seizure recording.