Abstracts

Rationale: Diagnosis of seizures and spells remains challenging and frequently requires prolonged EEG recording. Inpatient Video EEG monitoring is considered the gold standard but requires hospitalization and significant cost. Ambulatory EEG can provide similar information but is felt to be more limited and result in lower diagnsotic yield. We sought to determine the outcomes from ambulatory EEG and the factors affecting obtaining climnically useful information.Methods: We reviewed all patients undergoing ambulatory EEG monitoring over nine month period from September 2014 to May 2015. Medical records were reviewed to determine spell frequency, percentage of studies providing diagnosis and length of recording time needed to capture spells.Results: 67% studies resulted in positive findings potentially useful for clinical diagnosis. These included epileptiform abnormalities in 53% and recording of typical spell in 31 %. The duration of recording ranged from 1 to 5 days. The time to capture of first spell ranged from 1 to 2 days with a mean of 1.2 days.Conclusions: Ambulatory EEG provides useful information in the majority of patients with spells not sufficiently characterized by history. The duration of recording needed to record abnormalities may be shorter than inpatient VEEG recording. Our results suggest that optimal duration of ambulatory recordings is usually 1-2 days. Further studies are needed to determine the comparative utility of ambulatory EEG to inpatient VEEG recording.