Abstracts

Rationale: Traumatic brain injury (TBI) is a well-known risk factor for the development of epileptic seizures (ES), and is particularly relevant to Veterans due to the risk of military TBI. Retrospective studies have suggested that TBI may also be associated with the development of psychogenic non-epileptic seizures (PNES). We studied TBI as the proposed cause of seizures in Veterans with ES and PNES. Methods: The COVE (Characteristics of Veterans with Epilepsy) study prospectively evaluated all consenting Veterans entering the epilepsy monitoring units (EMUs) of the Portland Oregon, San Francisco California, and Madison Wisconsin VA Epilepsy Centers of Excellence. All patients underwent continuous video-EEG monitoring. Final EMU seizure diagnoses followed previously established research criteria. For this study we included only patients diagnosed with ES and PNES. Patients with mixed disorders were excluded. Research evaluations were performed in the EMU, prior to final diagnosis and patient debriefing. Evaluations included the Patient Seizure Etiology Questionnaire (PSEQ), a validated self-report instrument for determining whether patients attributed their seizures to civilian TBI(s), military TBI(s), or other causes. For patients with a proposed TBI seizure etiology, additional interview information included total number of TBIs, and maximum TBI severity (DoD classification). Psychiatric diagnoses were obtained using the Structured Clinical Interview for DSM IV (SCID). Severity of current post-traumatic stress disorder (PTSD) symptoms were measured using the PTSD checklist (PCL). Group statistical comparisons utilized Wilcoxon and Fisher’s exact tests. Results: The study included 71 patients with EMU verified ES, and 81 patients with EMU verified PNES. Based on PSEQ scores 25% of Veterans with ES indicated that TBI was the primary cause of their seizures, vs. 47% of Veterans with PNES (p ES) differences were significant for both civilian and military TBI (each p < 0.05). The median number of reported TBIs was higher in the PNES group (2, vs 1 in the ES group; p < 0.01). We compared patients with PNES who attributed seizures to a TBI (N=38) with those who did not (N=43). TBI patients had a longer length of military service (p < 0.05) and were more likely to have been deployed to a war theatre (p < 0.05). Age and gender were similar in the two groups, as were psychiatric diagnoses (SCID). Although PTSD was more frequent in patients with PNES vs. ES (64% vs. 13%; p < 0.001), PTSD diagnosis and PCL scores were similar in PNES patients with or without TBI. Conclusions: In this multicenter study, attribution of TBI as the primary cause of seizures was more common in Veterans ultimately diagnosed with PNES than in those diagnosed with ES. Patients with PNES also reported a higher total number of TBIs. The relatively high TBI prevalence reported in recent U.S. military conflicts represents a significant risk factor for both ES and PNES. Funding: Funded by the Department of Veterans Affairs