Abstracts

Rationale: Ambulatory EEG (AEEG) enables the patient to be studied in a more normal day-to-day environment for long periods of time less expensively than video EEG although with the disadvantage of unexplained artifacts. The current study assessed the efficacy of ambulatory EEG in helping to differentiate epileptic events from children who were referred primarily for staring episodes. Methods: The study was a retrospective chart review. Pediatric patients under the age of 18 years who were referred to the Baystate Medical Center and had undergone 18-channel ambulatory EEGs between January 2005 and December 2007 were identified. Patients referred because of “staring spells” or “transient alteration of awareness” were selected. Any subjects formally diagnosed with epilepsy or on any antiepileptic drugs were excluded. All AEEG reports were read by a single board-certified electroencephalographer/pediatric neurologist. Data was collected by reviewing AEEG reports in the computer chart. These included demographics, abnormal results, correlation between EEG finding and clinical or electrographic events. IRB approval was obtained prior to the chart review. Results: 100 patients (55 male) aged 3 months to 16 years were identified with a mean age of 6.7 years. 69 completed a 24-hour study while 31 completed a 48-hour study. 33/100 had abnormal EEG results. 16/33 demonstrated primary generalized epileptiform discharges while 15/33 demonstrated focal epileptiform discharges, of which 5 were consistent with Benign Rolandic Epilepsy. 2/33 showed nonspecific changes of unclear clinical significance. 7/33 showed definite electrographic seizure activity (6-typical absence seizures, 1-partial onset seizure). 38 parents noted clinical events during AEEG. Only 3 out of 38 parent-recorded events (8%) correlated with electrographic seizures. However, when parents noted more than 4 clinical events during the AEEG, 43% (3/7) correlated with electrographic seizures. Only 3/100 studies ended prematurely (2 - electrodes pulled off, 1 - equipment failure). Conclusions: AEEG detected absence seizures in 6% of children referred because of staring episodes. The majority of clinical events reported by parents (92%) were not epileptic, and presumably were behavioral phenomena. AEEG is well tolerated by children. Finally, AEEG is an invaluable tool in conjunction with clinical history to diagnose epilepsy in children.