Electroencephalographic findings and 5-year risk of posttraumatic epilepsy after mild traumatic brain injury: Insights from Second Karabakh War Veterans

Abstract: OBJECTIVE: This study aimed to investigate the long-term risk of posttraumatic epilepsy (PTE) and psychogenic nonepileptic seizures (PNES) following mild traumatic brain injury (mTBI) in combat veterans and to evaluate the predictive value of early electroencephalographic (EEG) abnormalities and the impact of trauma mechanism (blast vs. nonblast). METHODS: A retrospective observational study was conducted in 2000 war veterans followed for 5 years after the Second Karabakh War (2020-2025). Veterans with mTBI (n = 1000), defined by International Classification of Diseases, 10th Revision (ICD-10) code S06.0 and standard clinical criteria (loss of consciousness for ≤30 min, confusion for <24 h, normal computed tomography/magnetic resonance imaging), and controls without TBI (n = 1000) were compared for the incidence of PTE and PNES. Within the mTBI group, cases were stratified by trauma mechanism (blast-related vs. non-blast-related). Early EEGs (≤7 days) were analyzed for abnormalities predictive of PTE. PTE was defined as unprovoked seizures occurring >7 days after injury (ICD-10G40.x) and PNES as F44.5. Statistical analyses included chi-squared tests, Kaplan-Meier analysis, and Cox proportional hazards models. RESULTS: During the 5-year follow-up, epilepsy developed in 4.5% of the mTBI group compared with 1.3% of controls (p < .001). Blast-related injuries had a higher 5-year PTE incidence than nonblast trauma (5.7% vs. 2.3%, p = .019). More than half of PTE cases occurred within the first postinjury year. Early EEG abnormalities were observed in 20% of the mTBI group, and epileptiform discharges were strongly associated with subsequent PTE. PNES occurred in 7.1% of mTBI and 2.4% of controls (p < .001); 65% of PNES cases in the mTBI group were comorbid with PTSD. SIGNIFICANCE: Even mild TBI can induce long-term epileptogenesis, particularly after blast exposure. Early EEG abnormalities, especially epileptiform discharges, serve as strong predictors of PTE. These findings emphasize the need for early electrophysiological screening and long-term neuropsychiatric follow-up in veterans with mild head injury.