Abstracts

Rationale: Ambulatory EEG is an effective diagnostic test to determine seizure type and location of onset. While the ambulatory EEG can make testing more convenient for children and their families, it does not replace the utility of inpatient video EEG monitoring because characterization with video of event semiology is important for diagnosis and seizure localization. Ambulatory video-EEG (AVEEG) is now possible, but its diagnostic yield and impact on subsequent clinical care has not previously been examined. Methods: A retrospective review of 80 consecutive studies in patients 18 years old and younger was performed. A 72 hour AVEEG was acquired with synchronized digital video and EEG (non-invasive, scalp, 10/20 system) with a button provided to mark subjective events. Relevant clinical data was abstracted from the chart, including the indication, and if results lead to change in AEDs or management overall (e.g. withdrawal of medication). Results: The age of the patients at the time of study ranged between 9-18 years old, with a mean of 15.35 years of age. Forty-two AVEEGs were ordered to assess spells without a previous epilepsy diagnosis (A), 20 to assess response to treatment for epilepsy (B), 4 to assess new spells with a previous epilepsy diagnosis (C), 7 studies to guide the decision to reduce or withdraw AEDs in pts with prolonged seizure freedom (D), and 7 unclassified (E). Studies revealed: interictal epileptiform abnormalities (IEDs) in 33 (41%); focal slowing in 4 (5%), events of any type in 34 (43%). Of studies with events, 4 (12%) had electroclinical seizures, 1 (3%) had syncope, and 13 (38%) had behavioral events. Seven studies had events solely off video (21%). None of the AVEEGs captured subclinical seizures, clinical-only seizures, or psychogenic non-epileptic seizures (PNES). 41% of patients sent for a diagnostic study (A+C) captured an event. In addition, 39% of all the diagnostic studies yielded a new diagnosis. For all studies, AED changed in 24% and management in 29%. There was a trend demonstrating AED change associated with the presence of IED (p=0.0127) and electroclinical seizures (p=0.0312). Conclusions: Almost one-third of AVEEG studies lead to a change in management. There is a trend demonstrating the presence of IEDs and electroclinical seizures as predictors for change to AED regimen. AVEEG should be could be considered a useful diagnostic tool to assist the clinician in management decisions.