Premium
The progression of electrophysiologic abnormalities during epileptogenesis after experimental traumatic brain injury
Author(s) -
Reid Aylin Y.,
Bragin Anatol,
Giza Christopher C.,
Staba Richard J.,
Engel Jerome
Publication year - 2016
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.13486
Subject(s) - epileptogenesis , epilepsy , medicine , electroencephalography , anesthesia , traumatic brain injury , hippocampal formation , psychology , psychiatry
Summary Objective Posttraumatic epilepsy ( PTE ) accounts for 20% of acquired epilepsies. Experimental models are important for studying epileptogenesis. We previously reported that repetitive high‐frequency oscillations with spikes ( rHFOS s) occur early after lateral fluid percussion injury (FPI) and may be a biomarker for PTE . The objective of this study was to use multiple electrodes in rat hippocampal and neocortical regions to describe the long‐term electroencephalographic and behavioral evolution of rHFOS s and epileptic seizures after traumatic brain injury (TBI). Methods Adult male rats underwent mild, moderate, or severe FPI or sham injury followed by video–electroencephalography ( EEG ) recordings with a combination of 16 neocortical and hippocampal electrodes at an early, intermediate, or late time‐point after injury, up to 52 weeks. Recordings were analyzed for the presence of rHFOS s and seizures. Results Analysis was done on 28 rats with FPI and 7 shams. Perilesional rHFOS s were recorded in significantly more rats after severe (70.3%) than mild (20%) injury or shams (14.3%). Frequency of occurrence was significantly highest in the early (10.8/h) versus late group (3.2/h). Late focal seizures originating from the same electrodes were recorded in significantly more rats in the late (87.5%) versus early period (22.2%), occurring almost exclusively in injured rats. Seizure duration increased significantly over time, averaging 19 s at the beginning of the early period and 27 s at the end of the late period. Seizure frequency also increased significantly over time, from 4.4 per week in the early group to 26.4 per week in the late group. Rarely, rats displayed early seizures or generalized seizures. Significance FPI results in early rHFOS s and later spontaneous focal seizures arising from peri‐lesional neocortex, supporting its use as a model for PTE . Epilepsy severity increased over time and was related to injury severity. The association between early rHFOS s and later focal seizures suggests that rHFOS s may be a potential noninvasive biomarker of PTE.