Epilepsy Information

American Epilepsy Society Poster (Abst. 1.131)

The diagnostic yield of video-eeg in the inpatient versus ambulatory settings in adults with episodes of unclear nature

Authors: Evan Fertig, Enrique Feoli, Jomard Sabri, Christos Lambrakis, Olgica Laban-Grant, Salah Mesad, Jeffrey Politsky and Marcelo Lancman

In 2007, the International League Against Epilepsy (ILAE) recommended utilization of inpatient video-EEG (VEEG) for several indications including electro-clinical characterization of habitual seizures and differentiation of epileptic from non-epileptic conditions. Recently, advances in technology have enabled the recording of simultaneous digital video and digital EEG in the ambulatory setting. Ambulatory video-EEG (AVEEG) can provide quality comparable to inpatient VEEG studies. Since AVEEG permit flexibility of the recording environment, it can be performed at home, allowing for greater convenience and comfort for the patient as well as potentially being more cost-effective. An important limitation of AVEEG is that reductions in antiepileptic drugs (AEDs), which is a common occurrence in the inpatient video-EEG setting, are typically not advised given the lack of direct medical supervision. The purpose of this study is to compare the diagnostic yield and subsequent influence on clinical management of inpatient VEEG versus outpatient AVEEG for adults referred for paroxysmal episodes of unclear type. Additionally, the influence of prior prescribed AEDs on procedure selection and results will be examined.


A retrospective review was performed of 253 adults referred to evaluate paroxysmal events of unclear nature. Studies to quantify seizure frequency or to evaluate for epilepsy surgery were excluded. Study selection was based on physician and patient choice and insurance factors. Relevant clinical data was abstracted from the chart, including if results lead to change in AEDs or management overall (e.g., driving restrictions or referral to psychiatrist).

In analysis of the sample so far, 70 adults had inpatient and 183 had outpatient studies: the respective mean duration was 90.6 vs. 61.5 hrs (Mann-Whitney U=5064.5, p=.010). A new diagnosis was made in 52.9% vs. 31.1% (χ<+>2<+>=10.22, p=0.001), AEDs changed in 74.3% vs. 14.8% (χ<+>2<+>=73.35, n=234, p<0.001) and overall management changed in 84.3% vs. 28.4% (χ<+>2<+>=53.87, p<0.001). Those on AEDs prior were equally likely to have either study (χ<+>2<+>=0.004, p=.951), but with a higher diagnostic yield (RR=1.92, 95% CI [1.26, 2.92].

Inpatient VEEG was significantly more likely than ambulatory VEEGs to lead to a diagnosis and change in management, but at the expense of being significantly longer. Prior AEDs did not influence test choice, but were associated for both types of studies with a higher diagnostic rate. Analysis of a larger sample is ongoing which will include factors such as time to first diagnostic event.