High frequency oscillations and seizure frequency in patients with focal epilepsy.
High frequency oscillations (HFOs) have been associated with epileptogenicity. In rats, the extent of HFOs (>200 Hz) is correlated with seizure frequency. We studied whether the same applies to patients with focal epilepsy. Thirty-nine patients with intracerebral EEG sampled at 2000 Hz were studied for interictal ripples (80-250 Hz), fast ripples (FR, 250-500 Hz) and spikes. Seizure frequency before implantation was compared to numbers of channels with HFOs (>1/min). Analyses were repeated for HFO rates of >5, >10 and >20. Separate analyses were done for 25 patients with temporal lobe epilepsy only and for a selection of similar unilateral temporal channels in 12 patients. No linear correlation or trend was found relating the number of channels with HFOs and seizure frequency. There was a linear positive correlation between the number of channels with more than 20 FRs/min and seizure frequency. The hypothesis that the more tissue generating HFOs, the higher the seizure frequency, was not confirmed, though there might be a correlation for high FR rates.
Zijlmans
Maeike
M
Montreal Neurological Institute and Hospital, McGill University, 3801 University Street, Montreal (Québec), Canada H3A 2B4. g.j.m.zijlmans@umcutrecht.nl
Jacobs
Julia
J
Zelmann
Rina
R
Dubeau
François
F
Gotman
Jean
J
D000328:Adult; D003627:Data Interpretation, Statistical; D004569:Electroencephalography; D004828:Epilepsies, Partial / Q000453:epidemiology / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D012640:Seizures / Q000453:epidemiology* / Q000503:physiopathology; D013702:Temporal Lobe / Q000503:physiopathology