Abstracts

Rationale: To determine the incidence and clinical implications of small sharp spikes (SSS) in patients in the adult epilepsy monitoring unit (EMU). Methods: Two electrophysiologists reviewed the video-EEG records of consecutive patients from Mar 2013 to Feb 2019 in the adult EMU at University of Chicago Medical Center. SSS, interictal and ictal epileptiform discharges were identified. The clinical data of patients were extracted from the medical records. Results: A total of 909 patients were screened, with a mean age of 39.9±15.3 (mean±SD) and 354 (38.9%) were male. SSS were observed in 110 patients (12.10%), of which 32 (29.09%) were male with a mean age of 41.9±14.4. Of the 544 patients with definitive epilepsy based on standard interictal and ictal EEG patterns, 103 (18.9%) had SSS, whereas of the 365 patients without epilepsy, only 7 (1.9%) had SSS. There was a strong association between SSS and epilepsy (P<0.05). Five (11.1%) of the 45 patients with generalized epilepsy had SSS, whereas 96 (19.7%) of the 488 patients with focal epilepsies had SSS. Two (20%) of 10 patients with both generalized and focal epilepsies had SSS. Eighty-nine (21.7%) of 411 patients with temporal lobe epilepsy had SSS. Six (10.5%) of the 57 patients with frontal lobe epilepsy had SSS. One (11.1%) of the 9 patients with multifocal onset of seizures had SSS. None of the 8 patients with parietal lobe epilepsy or the 3 with occipital lobe epilepsy had SSS. Conclusions: There is a statistically significant association between SSS and epilepsy. SSS are more common in patients with temporal lobe epilepsy than in other epilepsies. These findings suggest that SSS might be an epileptic EEG marker, rather than a benign EEG variant as commonly believed. Funding: No funding