Electroencephalogram (EEG) Spike Metrics Discriminate Impending Epileptic Spasms From Other Seizures in Children With Tuberous Sclerosis Complex: A Pilot Study

In data from a multicenter prospective observational study, we assessed whether interictal epileptiform discharge metrics in the pre-seizure onset surveillance scalp electroencephalograms (EEGs) in children with tuberous sclerosis complex could predict seizure outcomes, specifically epileptic spasms. In 16 children with eligible EEG data (7 with epileptic spasms and 9 with other seizure types) and 16 controls, 2 spike metrics were calculated through automated detection followed by expert review: (1) spike rate (spikes per minute) and (2) number of unique spike foci. In patients who developed seizures, a combination of spike rate threshold of ≥2 per minute and ≥2 unique spike foci during sleep was highly predictive of impending epileptic spasms (100% positive predictive value, 2 false negatives). One control patient was falsely predicted to develop epileptic spasms, decreasing the overall positive predictive value to 83.3%. These findings suggest that EEG spike metrics could predict impending epileptic spasms in children with tuberous sclerosis complex, pending larger-scale validation.