Abstracts

Rationale: Sleep disordered breathing is a common medical condition. It can lead to excessive daytime sleepiness, neuropsychological slowing, lapses of consciousness and accidents that can be misinterpreted as epileptic phenomena. Moreover, patients with documented epilepsy commonly exhibit similar symptomatology due to undiagnosed sleep apnea. Therefore a large proportion of patients referred to the EEG lab primarily to confirm or refute the diagnosis of epilepsy could suffer from latent sleep apnea and the routine EEG has the potential to divulge it. Methods: We retrospectively evaluated the reporting of sleep apnea symptomatology in routine inpatient and outpatient adult EEG studies performed in our institution over the past 12 years. Comparisons were performed with the medical records to ascertain the co-existence of objectively diagnosed sleep disordered breathing with polysomnography before or after the EEG study and the importance of reporting variations in assisting with the diagnosis. Results: 69 EEG studies were identified. The mean age of the subjects at EEG was 64 years (range 30-89) and 55 (80%) were male. 36% of them suffered from known epilepsy. Snoring was the most commonly reported sign in 48 (70%), followed by arousals in 29 (42%), apnea in 16 (23%), excessive drowsiness in 13 (19%), gasping/deep breath in 9 (13%) and desaturation in 7 (10%). A sleep disorder was suggested in 25 (36%) of the interpretations and a direct recommendation for a sleep study was made in 22 of them (32%). This interpretation was included in the impression of the report in 21 (30%) of the cases, in the detail in 20 (30%) of the cases and in both in 28 (40%). 14 (20%) patients were formally diagnosed with sleep disordered breathing through polysomnography. 7 (50%) of them were diagnosed with obstructive sleep apnea, 2 (14%) with central sleep apnea, 3 (22%) with both, 1 (7%) with upper airways resistance syndrome and 1 (7%) with primary snoring. From these 14 patients, 9 (64%) were diagnosed with a sleep study performed after the EEG, 4 (29%) before the EEG interpretation and 1 (7%) had a repeat study after the EEG. In the adjusted analysis performed, with the exception of the presence of arousals (OR=4.63, p=0.033), none of the aforementioned symptomatology or the reporting of suspicion for sleep disordered breathing or the location (impression vs. detail) of the reporting was significantly associated with the completion of a sleep study. Conclusions: Routine EEG offers a unique opportunity of direct clinical observation along with electrophysiologic and cardiac monitoring. When sleep is recorded, it can help identify clinical and electrographic features of sleep apnea and prompt confirmation with a polysomnogram. It can therefore serve as a valuable, adjunctive screening tool for the diagnosis of sleep disordered breathing. Our data highlight that potential but unveil its decreased utilization in the neurology community. Increased awareness is required by the EEG technologists, interpreting neurologists and referring physicians, regarding reporting and utilizing sleep apnea features on the EEG.