Spike detection in the wild: Screening of suspected temporal lobe epilepsy cases using a tailored 2-channel wearable EEG.

Abstract

Objective: To clinically validate the contribution of a custom-built EEG wearable device (waEEG) compared to a full 10-20 electrode array ambulatory EEG (aEEG) for screening epilepsy cases in patients with suspected temporal lobe epilepsy (TLE) but negative routine EEGs.

Methods: Patients (aged 16-91 years) with clinically suspected TLE who were referred for a 24 h aEEG were fitted with an additional 2-channel bipolar waEEG device and prospectively enrolled in the study until 20 TLE diagnoses were confirmed by aEEG. 41 patients were included and their waEEG was blindly reviewed by two experienced clinical neurophysiologists and a semi-automated spike detection software to categorize patients into TLE (spikes present) and non-TLE (no spikes) groups.

Results: The experts achieved good sensitivity (95%-100%) and accuracy (98%-93%) with excellent interrater agreement (kappa>0.80) in patient labelling. The semi-automated software performed poorly (40% sensitivity, 68% accuracy) and failed to classify TLE in more than half the cases. Classification was not affected by restricting spike detection to the evening and night time, which reduced the average length of the analyzed EEG from 23.4 to 10.4 h. Three false-positive spike detections were thoroughly analyzed and reclassified as artifacts due to eye and body movements and electrocardiographic contamination. To better control cardiac artifacts, the addition of an ECG channel to the waEEG is recommended.

Significance: Detection of spikes with waEEG allows accurate detection of epilepsy in suspected TLE cases, with less technical and professional effort and improved acceptance. This screening tool could improve the yield of follow-up with a conventional aEEG and provide an accessible method for monitoring interictal epileptiform activity in TLE.

Plain language summary: Epilepsy is a chronic short circuit in the brain. In adults, it most often affects the temporal lobes, resulting in temporal lobe epilepsy (TLE). Seizures are infrequent but difficult to treat. Electroencephalography (EEG) is the best method to detect the electrical disturbances and is crucial to distinguish epilepsy from other non-epileptic disorders. Developing simple, inexpensive and easily accessible portable EEG methods that complement in-hospital assessment could significantly impact patient care. Our study aims to clinically validate a wearable epilepsy screening device to aid in TLE management, reduce delays in diagnosis and enable straightforward assessment of epileptic activity.