Auras localized to the temporal lobe disrupt verbal memory and learning — Causal evidence from direct electrical stimulation of the hippocampus

Abstract

Auras (focal aware seizure; FAS) are subjective ictal events with retained consciousness. Epileptiform activities can disrupt cognitive tasks, but studies are limited to seizures with impaired awareness. As a proof of concept, we examined the cognitive effects of direct electrical stimulation to the left hippocampus which induced a habitual FAS in a patient with left mesial temporal lobe epilepsy. During the induced habitual FAS, verbal memory performance declined significantly as compared to pre-stimulation testing. Tasks measuring auditory working memory and psychomotor processing speed were not affected by the stimulation. The study confirms that FAS can impair episodic verbal memory and learning.

Long-term seizure freedom following intracranial sEEG monitoring: Therapeutic benefit of a diagnostic technique

“…Patient 1 had also undergone extra-operative direct cortical stimulation of the hippocampal electrode for functional mapping of the memory with sustained stimulation [14,15]. It is unclear if this approach had any contribution to seizure remission [16].…”

Validation of direct cortical stimulation in presurgical evaluation of epilepsy

“…The primary objectives of DCS are the definition of the EZ and cortical mapping (Bank et al, 2014, Kovac et al, 2016, Huang et al, 2019Boido et al, 2014;Dionisio et al, 2019;Sarubbo et al, 2020;David et al, 2008David et al, , 2010David et al, and 2013Rahimpour et al, 2019;Boyer et al, 2020;Pizarro et al, 2018;Bartolomei et al, 2004;Kahane et al, 2003;Ojemann et al, 2008). For the evaluation of the EZ, most centers use high-frequency stimulations (50 Hz), while others also apply lowfrequency pulses at 1 Hz for longer periods.…”