Abstract

Background: Traumatic brain injury (TBI) is an important cause of focal epilepsy. Animal experiments indicate that disruption of the blood-brain barrier (BBB) plays a critical role in the pathogenesis of post-traumatic epilepsy (PTE).

Objective: To investigate the frequency, extent and functional correlates of increased BBB permeability following in PTE patients.

Methods: 32 head trauma patients were included in the study, with 17 suffering from PTE. Patients underwent brain magnetic resonance imaging (bMRI) and were evaluated for BBB disruption, using a novel semi-quantitative technique. Cortical dysfunction was measured using electroencephalography (EEG), and localized using standardized low resolution brain electromagnetic tomography (sLORETA).

Results: Spectral EEG analyses revealed significant slowing in TBI patients with no significant differences between epileptic and non-epileptic patients. While bMRI revealed that PTE patients were more likely to present with intracortical lesions (p=0.02), no differences in the size of the lesion were found between the groups (p=0.19). Increased BBB permeability was found in 76.9% of PTE compared to 33.3% of non-epileptic patients (p=0.047), and could be observed years following the trauma. Cerebral cortex volume with BBB disruption was larger in PTE patients (p=0.001). In 70% of patients, slow (delta band) activity was co-localized, by sLORETA, with regions showing BBB disruption.

Conclusions: Lasting BBB pathology is common in mild TBI patients, with increased frequency and extent in PTE patients. A correlation between disrupted BBB and abnormal neuronal activity is suggested.