Abstracts

Post-traumatic epilepsy (PTE) is a common and frequently disabling complication of moderate and severe traumatic brain injury (TBI). PTE is often refractory to medical treatment and commonly presents diagnostic and therapeutic challenges. This study was undertaken to assess the clinical utility of long-term video-EEG monitoring evaluation of patients with medically refractory PTE.
The records of 1634 patients consecutively referred for video-EEG monitoring from January, 1998 to December, 2002, were reviewed. Patients and family members were questioned as to possible risk factors for epilepsy. Patients were included if they sustained moderate to severe TBI before the onset of epilepsy. Moderate to severe TBI was defined as injury resulting in prolonged ([gt]30 minute) loss of consciousness or amnesia, hospitalization, or neuroradiologic evidence of TBI. All patients underwent surface ictal and interictal video EEG recordings, and data were reviewed by board-certified clinical neurophysiologists. All patients also underwent magnetic resonance imaging (MRI) using a technique sensitive for detecting sclerosis of the mesial temporal structures.
131patients (8% of patients evaluated over 4 years) met inclusion criteria. All were suffering from frequent, disabling spells, which had been diagnosed as epileptic by the referring physicians. All but two were being treated with antiepileptic drugs, in most cases with combinations of these. Video-EEG evaluation was effective in establishing a diagnosis in 108 (82%). The average duration of monitoring was 4.6 days (SD 2.4, median 4), and was not different for the nondiagnostic cases. Of the diagnosed cases, 68 (63%) had epileptic seizures recorded, which were temporal in 35 (32%), frontal in 21 (19%), parietal in 3 (3%), and occipital in 2 (2%). Of the temporal lobe epilepsy cases, 18 (51%) had mesial temporal sclerosis. An additional 7 patients (6%) had generalized epileptic disorders, of which 4 had the clinical features of idiopathic generalized epilepsy. 39 patients (29.7% of the total cohort) had psychogenic nonepileptic seizures (NES) as the exclusive seizure type recorded.
The diagnostic yield of a reasonably short evaluation (average under 5 days) was high. As previously reported from PTE series that did not rely on video-EEG, temporal lobe seizures are most common. Half of temporal lobe cases have mesial temporal sclerosis on MRI, and may be good candidates for surgical therapy. A small but significant fraction of patients have generalized epileptic disorders, a finding which may have therapeutic implications. A subtantial fraction of subjects referred with a diagnosis of medically intractable PTE had psychogenic NES, which requires substantially different treatment. We conclude that video-EEG evaluation is indicated in survivors of moderate to severe TBI who are experiencing disabling seizures.
[Supported by: NIH RO1 AG17869, RO3 MH64889, and NIDRR H133A02052601.]