Abstracts

Rationale: EEG-video monitoring is the mainstay of epilepsy centers, but epilepsy monitoring units frequently have long backlogs and waiting periods. Most literature on ambulatory EEG refer to studies without video, and EEG-video is assumed to imply the inpatient setting. However, in the last decade, technology has made ambulatory EEG-video possible. The purpose of this study was to review the yield of ambulatory EEG-video monitoring. Methods: We retrospectively reviewed 200 consecutive unselected ambulatory EEG-video monitoring performed by a single company (RSC Diagnostic Services, Richardson, TX) between January 12, and May 1, 2018. Studies were reviewed and processed by certified long-term monitoring EEG technologists, and interpreted by neurologists. Children younger than 12 years were not included. Results: There were 130 females and 70 males, with ages ranging from 12 to 101 years (mean 45).  Duration of the studies ranged from 23 to 175 hours (mean 76.6). In 110 (55%) studies, clinical events were recorded. Time from study start to first event recorded ranged from 1 to 115 hours (average 21.8). Of the 110 studies with events recorded, 101 (92%) had events recorded on camera.Outcome: was as follows:94 studies (47%), were conclusive, with a definite diagnosis (event on camera). The conclusion was epileptic in 19, and nonepileptic in 75.29 studies (14.5%) were partially conclusive: events recorded without EEG correlate but interictal epileptiform discharges (4); events recorded but not on camera (8); no events but clear interictal epileptiform abnormalities (17).70 studies (35%) were inconclusive: no events and normal EEG (59); no events with abnormal {non-epileptiform} EEG (11).Others miscellaneous outcomes: Atypical event without EEG correlate (4); uninterpretable (3). Conclusions: When an event was recorded, 92% of the time it was captured on video.A definite diagnosis could be obtained ~50% of the time.Obtaining a definite diagnosis of non-epileptic events (37.5%) is useful and could  obviate or prioritize the need for inpatient EEG-video monitoring.The relatively high proportion of inconclusive studies (35%) can be explained by the fact that many studies were not ordered with the intent of recording an event. Ambulatory EEG-video monitoring is a useful alternative to inpatient monitoring. Funding: None