High amplitude high frequency oscillations during posttraumatic epileptogenesis

Abstract

Background: The aim of the present study was to investigate if high amplitude high frequency oscillations (haHFOs) could be a biomarker of posttraumatic epileptogenesis. Methods: After an initial craniotomy of rats and inducement of traumatic brain injury (TBI) through a fluid percussion, recording microelectrodes were implanted bilaterally in different brain areas. Wideband brain electrical activity was recorded intermittently from Day 1 of TBI and continued till week 21. HaHFO analysis was performed during the first 4 weeks to investigate whether the occurrence of this brain activity predicted development of epilepsy or not. Results: Of the 21 rats which received the TBI, 9 became epileptic (E+) and 12 did not (E−). HaHFOs were observed in the prefrontal and perilesional cortices, hippocampus, and striatum in both E+ and E− group. In comparison to the rats in E−, the E+ group showed a significant increase in the rate of haHFO from weeks 1 to 4 after TBI. Conclusion: The results indicate that an increase in the rate of haHFOs after TBI could be an electroencephalographic biomarker of posttraumatic epileptogenesis.