Summary:Purpose: Prospective evaluation of risk factors for posttraumatic epilepsy (PTE) by using clinical, EEG, and brain computed tomography (CT) data in four assessments from the head injury (HI) acute phase to 1 year later; and evaluation of the possible epileptogenic role of hemosiderin as shown by brain magnetic resonance imaging (MRI).Methods: Risk factors for PTE were evaluated by using Kaplan-Meier curves, log-rank test, and the Cox model in 137 consecutively enrolled adult inpatients. Percentage differences of patients with brain hyperintense and/or hemosiderin areas shown by MRI 1 year after HI were statistically evaluated by univariate tests considering two subgroups [e.g., patients with (FTE) and without (WLS) late seizures].Results: The PTE subgroup included 18 patients with at least two seizures between the second and twelfth months. KaplanMeier curves demonstrated that Glasgow Coma Scale low score, early seizures, and single brain CT lesions are PTE risk factors, as is the development of an EEG focus 1 month after HI. No significant percentage difference was found between PTE and WLS patients with hemosiderin spots shown by MRI 1 year after HI.Conclusions: the Cox model indicates that, for HI patients with early seizures and brain CT single temporal or frontal lesions in the acute phase, the PTE risk is 8.58 and 3.43 times higher, respectively, than for those without. An EEG focus 1 month after HI is a risk factor 3.49 times higher than for patients without such EEG changes. One year after HI, a higher percentage of PTE than WLS patients had cortical MRI hyperintense areas including hemosiderin. Key Words: Posttraumatic epilepsy-Clinical-Brain CT-MRI-EEG follow-upHemosiderin.Posttraumatic epilepsy (PTE), known since the time of Hippocrates, is still a puzzle because of the variety of methods used in the different studies and the wide range of their results. Dalmady-Israel and Zasler ( I ) provided a critical analysis of the literature on PTE emphasizing the lack of standardized definitions of both epilepsy and head injury (HI). Differences in inclusion/exclusion criteria and inadequacy in the follow-up of patients generate inconclusive or controversial results on incidence and risk factors.Many of the retrospective studies evaluated outcome when there was no standardized way of managing the
Electroencephalographic (EEG) patterns were analyzed in a group of ambulatory patients who ranged in age and sex using spectral analysis as well as Directed Transfer Function, a method used to evaluate functional brain connectivity. We tested the impact of window size and choice of reference electrode on the identification of two or more peaks with close frequencies in the spectral power distribution, so called “split alpha.” Together with the connectivity analysis, examination of spatiotemporal maps showing the distribution of amplitudes of EEG patterns allowed for better explanation of the mechanisms underlying the generation of split alpha peaks. It was demonstrated that the split alpha spectrum can be generated by two or more independent and interconnected alpha wave generators located in different regions of the cerebral cortex, but not necessarily in the occipital cortex. We also demonstrated the importance of appropriate reference electrode choice during signal recording. In addition, results obtained using the original data were compared with results obtained using re-referenced data, using average reference electrode and reference electrode standardization techniques.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.