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Interictal epileptiform discharges impair word recall in multiple brain areas
Author(s) -
Horak Peter C.,
Meisenhelter Stephen,
Song Yinchen,
Testorf Markus E.,
Kahana Michael J.,
Viles Weston D.,
Bujarski Krzysztof A.,
Connolly Andrew C.,
Robbins Ashlee A.,
Sperling Michael R.,
Sharan Ashwini D.,
Worrell Gregory A.,
Miller Laura R.,
Gross Robert E.,
Davis Kathryn A.,
Roberts David W.,
Lega Bradley,
Sheth Sameer A.,
Zaghloul Kareem A.,
Stein Joel M.,
Das Sandhitsu R.,
Rizzuto Daniel S.,
Jobst Barbara C.
Publication year - 2017
Publication title -
epilepsia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.687
H-Index - 191
eISSN - 1528-1167
pISSN - 0013-9580
DOI - 10.1111/epi.13633
Subject(s) - ictal , recall , temporal lobe , psychology , epilepsy , electroencephalography , neuroscience , audiology , lateralization of brain function , episodic memory , cognitive psychology , cognition , medicine
Summary Objectives Interictal epileptiform discharges ( IED s) have been linked to memory impairment, but the spatial and temporal dynamics of this relationship remain elusive. In the present study, we aim to systematically characterize the brain areas and times at which IED s affect memory. Methods Eighty epilepsy patients participated in a delayed free recall task while undergoing intracranial electroencephalography ( EEG ) monitoring. We analyzed the locations and timing of IED s relative to the behavioral data in order to measure their effects on memory. Results Overall IED rates did not correlate with task performance across subjects (r = 0.03, p = 0.8). However, at a finer temporal scale, within‐subject memory was negatively affected by IED s during the encoding and recall periods of the task but not during the rest and distractor periods (p < 0.01, p < 0.001, p = 0.3, and p = 0.8, respectively). The effects of IED s during encoding and recall were stronger in the left hemisphere than in the right (p < 0.05). Of six brain areas analyzed, IED s in the inferior‐temporal, medial‐temporal, and parietal areas significantly affected memory (false discovery rate < 0.05). Significance These findings reveal a network of brain areas sensitive to IED s with key nodes in temporal as well as parietal lobes. They also demonstrate the time‐dependent effects of IED s in this network on memory.