The clinical significance of small sharp spikes: A retrospective study of 909 patients in epilepsy monitoring unit

Abstract

ObjectivesTo determine the incidence and clinical significance of small sharp spikes (SSS) in the patient population of the adult Epilepsy Monitoring Unit (EMU). MethodsThis is a retrospective study of EEG data and medical records from consecutive patients who underwent video-EEG recording in the adult EMU from March 2013 to February 2019. SSS, interictal epileptiform discharges (IEDs), and ictal patterns were identified. ResultsOf the 909 patients reviewed, SSS were observed in110 (12.1 %) patients. Epilepsy was present in 101 of the 110 (91.8 %) patients with SSS and in 441 of the 799 (55.2 %) patients without SSS. The incidence of epilepsy was significantly higher in patients with SSS than in those without SSS (OR = 9.1, 95 % CI: 4.5–18.3, P < 0.01). The sensitivity of SSS for epilepsy was 18.6 % and the specificity was 97.5 %. The incidence of SSS was strongly correlated with the frequency of IEDs (OR 1.89; 95 %CI: 1.60–2.24, P < 0.01). When both present, SSS and IEDs were co-lateralized in the same hemisphere. ConclusionsThere is a statistically significant association between SSS and focal epilepsy. SSS have similar clinical implications to IEDs in the lateralization and localization of temporal lobe seizures. SSS can be an epileptiform EEG pattern for temporal lobe epilepsy.