Assistant proffesor University of Florida Gainesvile, Florida
This abstract has been invited to present during the Better Patient Outcomes through Diversity Platform poster session
Rationale: The scalp EEG is one of the main tools used in the diagnosis, classification, and pre-surgical evaluation of epilepsy. The objective of this study is to identify scalp EEG correlates of hippocampal spikes in patients with mesial temporal lobe epilepsy (mTLE). Methods: We recorded scalp and intracranial EEG simultaneously in 20 consecutive surgical candidates with mTLE. Hippocampal spikes were identified from depth electrodes during the first hour of stage I and II sleep on the first night of recording in our epilepsy monitoring unit, and their scalp EEG correlates were identified. Results: Hippocampal spiking rates varied widely from 101 to 2,187 spikes per hour among the subjects. A total of 16,398 hippocampal spikes were observed. When propagated to anterior and/or basolateral neocortex, only 475 (2.9%) hippocampal spikes were associated with conventional scalp interictal epileptiform discharges (IEDs) including spikes and sharp waves. Hippocampal spikes with mesiobasal temporal propagation were often associated with small sharp spikes (SSS) and sharp transients. SSS were not associated with independent neocortical spikes. Conclusions: Scalp EEG correlates of hippocampal spikes are morphologically heterogeneous with a spectrum of patterns including SSS, sharp transients, sharp slow waves, spikes and sharp waves, reflecting variable extents of propagation of hippocampal spikes to basal, anterior and lateral temporal neocortex. Scalp IEDs are associated with a minority of hippocampal spikes. SSS, but not scalp spikes and sharp waves, differentiate the mesial from neocortical temporal spiking sources. Funding: Please list any funding that was received in support of this abstract.: NA Click here to view image/table
