Abstracts

RATIONALE: Distinguishing epileptic from non-epileptic events (NEE) in patients with cognitive handicaps or mental retardation (MR) is often challenging. Patients with MR have an increased incidence of epilepsy and associated medical conditions that can be confused with epilepsy. In addition, they often have repetitive behaviors, and limited verbal skils to report symptoms. We investigated the proportion of NEE confused as epilepsy in this population by use of video-EEG telemetry.
METHODS: We prospectively followed patients admitted for video-EEG monitoring to our institution for suspected seizures for one year. Clinical history of the events was obtained by the referring physician, from family members or guardians, and reviewed on admission by the medical and EEG staff. Only events suggestive of potential seizures were documented and reviewed on digital video and EEG monitoring which were then read by the authors. Additional information on the patients[ssquote] history were obtained from the medical charts.
RESULTS: 164 patients were admitted to Columbus Children[ssquote]s Hospital for video-EEG monitoring over a one year period to characterize new or existing seizure types, and of these, 75 (46%) had MR. 25/75 (33%) were diagnosed as having NEE. Of these patients, 21/25 (84%) had abnormal interictal EEGs. 19/25 (76%) had concurrent epilepsy, of which 12 (48%) were medically intractable. 21 (84%) were being treated with anti-epileptic drugs (AEDs) (mean=1.6; range= 0-5). 17/25 (68%) had more than 1 symptom or episode (mean=2, range= 1-4).
51total symptoms/events were then analyzed. The majority (51%) consisted of abnormal movements such as eye and mouth movements and tonic posturing. 35% had behavorial events (staring, self-stimulation, stereotypies). The remainder had sleep disturbances (5) or other manifestations (oxygen desaturation and dizziness - 2).
After video-EEG diagnosis of NEE, the majority of patients (56%) had no additional AEDs added. 28% had their AED therapy decreased or discontinued. 4 patients had not been treated with AEDs prior to the study, and remained off AED therapy.
CONCLUSIONS: In the cognitively handicapped population, NEE could not be predicted based on interictal EEG findings or the clinical characteristics of the events. These results are similar to previous studies in this population (Donat et al., 1990; Holmes et al., 1983). In contrast to those earlier studies, however, a far greater proportion of patients with MR now referred for video-EEG monitoring have concurrent epilepsy (76% in this study compared to 40% in the previous studies), of which 50% were intractable. This finding demonstrates the importance of video-EEG monitoring in patients with MR, a population in which stereotypical behaviors, abnormal interictal EEGs, and underlying epilepsy are frequently present.
[Supported by: Children[ssquote]s Hospital, Columbus, Ohio]; (Disclosure: Grant - Glaxo-Wellcome, Elan Pharmaceuticals, UCB Pharmaceuticals, Consulting - Glaxo-Wellcome, Elan Pharmaceuticals, X-Cell Pharmaceuticals, Ortho-MacNeill, UCB Pharmaceuticals, Novartis, Honoraria - Glaxo-Wellcome, Elan Pharmaceuticals, X-Cell Pharmaceuticals, Ortho-MacNeill, UCB Pharmaceuticals, Novartis)