Abstracts

EEG-video monitoring is critical for epilepsy surgery evaluation and epilepsy diagnosis. The purpose of this study was to determine the sensitivity and limitations of EEG-video monitoring.
We retrospectively reviewed EEG-video data. We determined the median time to first, second and third epileptic seizures and median time to a non-epileptic event. The patient groups were an epilepsy surgery group and a seizure characterization group. We differentiated epileptic seizures from non-epileptic events in the seizure characterization group. We determined the success rate for differentiating epileptic from non-epileptic events.
There were 111 cases (43 males, 68 females; age 2-90 years, median 33 years). The diagnoses were: partial seizures: 66 cases, primary generalized seizures: 7 cases, non-epileptic events: 12 cases, non-epileptic events and epileptic seizures: 2 cases and no diagnosis: 24 cases. There were 52 epilepsy surgery cases and 59 seizure characterization cases. EEG-video monitoring established a diagnosis in 36 (61%) patients in the seizure characterization group. Epileptic seizures were recorded in 47 (90%) patients in the epilepsy surgery group. The median times to record the first, second and third seizures were 26 hours, 48 hours and 54 hours. The median time to record a non-epileptic event was 14 hours. Epileptiform discharges occurred in 65 cases; discharges occurred in 56 (86%) of patients within 1 day of monitoring; in the remaining 9 cases epileptiform discharges occurred within 2-4 days of monitoring.
This study provides detailed information on the diagnostic sensitivity and time estimates to achieve diagnosis of epileptic and non-epileptic events. This data provides a useful guideline for estimating the appropriate lengths of stay for inapatient monitoring. Monitoring may fail to record epileptiform discharges (single day monitoring) or epileptic seizures (multi-day monitoring) in a significant minority of epilepsy patients.