Interictal Epileptiform Discharges Impair Performance Across Cognitive Domains
Abstract number :
2.023
Submission category :
3. Neurophysiology / 3C. Other Clinical EEG
Year :
2022
Submission ID :
2204337
Source :
www.aesnet.org
Presentation date :
12/4/2022 12:00:00 PM
Published date :
Nov 22, 2022, 05:24 AM
Authors :
Alexander Silva, BS – University of California San Francisco; Yulia Oganian, PhD – University Tübingen, Tübingen, Germany; Matt Leonard, PhD – University of California, San Francisco, CA, USA; Devon Krish, High School – University of California, San Francisco, CA, USA; Edward Chang, MD – University of California, San Francisco, CA, USA; Jonathan Kleen, MD, PhD – University of California, San Francisco, CA, USA
Rationale: Cognitive dysfunction is a common and severe comorbidity associated with long term epilepsy. Previous research has shown that interictal bursts of abnormal neural activity, termed interictal epileptiform discharges (IEDs), temporarily impair memory. However, studies of this transient cognitive impartment (TCI) phenomenon are usually limited to short-term memory, particularly episodic memory tasks assessing free recall of information presented in the same session. Yet, diverse types of cognitive impairments are associated with epilepsy, and thus an outstanding question is whether TCI generalizes to other cognitive domains in the same patient cohort. Here, we compare the effects of IEDs across free recall, repetition, and auditory naming tasks, and hypothesize that TCI in humans would extend to additional cognitive domains depending on where (anatomically) IEDs occur.
Methods: We used high-density intracranial EEG to record from deep brain and superficial cortical structures in participants with epilepsy (N=22) being monitored for clinical purposes. These patients volunteered to perform 3 tasks in order: auditory naming (eg., An animal that says meow → “cat”), free recall (as a positive control), and simple word repetition. IEDs were detected using a linelength-based algorithm coupled with manual verification, then grouped into five anatomical regions: hippocampus/mesial temporal lobe (MTL), supralateral temporal (MTG/STG), inferior temporal gyrus, precentral gyrus, and prefrontal cortex. We applied generalized linear mixed effects models to predict the effects of IEDs in each anatomical region on reaction time across the three tasks and correct responses in auditory naming.
Results: We first confirmed prior research using the free recall task, in which MTL IEDs were associated with decreased encoding and retrieval of stimuli (p < 0.005 for both). In the repetition task, STG/MTG IEDs increased reaction time (P < 0.005) but not IEDs in the other four regions. Strikingly, in the auditory naming task, IEDs in the MTL (but no other region tested) decreased probability of a correct response (P < 0.005). IEDs in both the STG/MTG and prefrontal regions increased reaction time in this same task (P < 0.05).
Neurophysiology