Greta Macorig1, Arielle Crespel2, Annacarmen Nilo3, Ngoc Phuong Loc Tang4, Mariarosaria Valente5, Gian Luigi Gigli6, Philippe Gélisse7. 1. Gui de Chauliac Hospital, Epilepsy Unit, Montpellier, France; San Giovanni di Dio Hospital, Neurology Unit, Gorizia, Italy. 2. Gui de Chauliac Hospital, Epilepsy Unit, Montpellier, France; Institut National de la Santé et de la Recherche Médicale (INSERM), Unité de Recherche sur les Comportements et Mouvements Anormaux, Montpellier, France. 3. Gui de Chauliac Hospital, Epilepsy Unit, Montpellier, France; S. Maria della Misericordia University Hospital, Clinical Neurology Unit, Udine, Italy. 4. Gui de Chauliac Hospital, Epilepsy Unit, Montpellier, France. 5. S. Maria della Misericordia University Hospital, Clinical Neurology Unit, Udine, Italy; University of Udine, Department of Medicine, Udine, Italy. 6. S. Maria della Misericordia University Hospital, Clinical Neurology Unit, Udine, Italy; University of Udine, Department of Mathematics, Computer Science and Physics, Udine, Italy. 7. Gui de Chauliac Hospital, Epilepsy Unit, Montpellier, France; Institut National de la Santé et de la Recherche Médicale (INSERM), Unité de Recherche sur les Comportements et Mouvements Anormaux, Montpellier, France. Electronic address: p-gelisse@chu-montpellier.fr.
Abstract
OBJECTIVES: To study the prevalence of benign EEG variants (BEVs) in the sleep-wake cycle among 1163 consecutive patients. METHODS: Prospective, observational EEG study using the 10-20 system with systematically two additional anterior-temporal electrodes. Depending on clinical indications, other electrodes were added. REM sleep identification was based on its characteristic EEG grapho-elements and rapid eye movements, clearly detectable with the additional anterior-temporal and fronto-polar electrodes due to eye proximity. The video-EEG monitoring duration was between 24hours and eight days. RESULTS: We identified 710 patients (61%) with BEVs. Positive occipital sharp transients of sleep (POSTs) were observed in 36.4% of participants, mu rhythm in 22.4%, lambda waves in 16.7%, wicket spikes (WS) in 15%, 14- and 6-Hz positive bursts in 8.3%, benign sporadic sleep spikes (BSSS) in 3.3%, rhythmic mid-temporal theta burst of drowsiness (RMTD) in 2.15%, midline theta rhythm in 2.1% and six-Hz spike and wave (SW) bursts in 0.1%. WS and RMTD were present during wakefulness, NREM (14.1%, 1.3%, respectively) and REM sleep (3.3%, 1.1%, respectively). Mu rhythm was also observed during NREM (1.5%) and REM sleep (7.7%). Fourteen- and 6-Hz positive bursts were present during NREM (4.5%) and REM sleep (6.5%). BSSS and six-Hz SW bursts were only observed during NREM sleep. CONCLUSIONS: The prevalence of BEVs is much higher than current estimates. POSTs and WS can no longer be considered as unusual patterns but physiological patterns of NREM sleep. RMTD and mu rhythm may be observed during NREM and REM sleep.
OBJECTIVES: To study the prevalence of benign EEG variants (BEVs) in the sleep-wake cycle among 1163 consecutive patients. METHODS: Prospective, observational EEG study using the 10-20 system with systematically two additional anterior-temporal electrodes. Depending on clinical indications, other electrodes were added. REM sleep identification was based on its characteristic EEG grapho-elements and rapid eye movements, clearly detectable with the additional anterior-temporal and fronto-polar electrodes due to eye proximity. The video-EEG monitoring duration was between 24hours and eight days. RESULTS: We identified 710 patients (61%) with BEVs. Positive occipital sharp transients of sleep (POSTs) were observed in 36.4% of participants, mu rhythm in 22.4%, lambda waves in 16.7%, wicket spikes (WS) in 15%, 14- and 6-Hz positive bursts in 8.3%, benign sporadic sleep spikes (BSSS) in 3.3%, rhythmic mid-temporal theta burst of drowsiness (RMTD) in 2.15%, midline theta rhythm in 2.1% and six-Hz spike and wave (SW) bursts in 0.1%. WS and RMTD were present during wakefulness, NREM (14.1%, 1.3%, respectively) and REM sleep (3.3%, 1.1%, respectively). Mu rhythm was also observed during NREM (1.5%) and REM sleep (7.7%). Fourteen- and 6-Hz positive bursts were present during NREM (4.5%) and REM sleep (6.5%). BSSS and six-Hz SW bursts were only observed during NREM sleep. CONCLUSIONS: The prevalence of BEVs is much higher than current estimates. POSTs and WS can no longer be considered as unusual patterns but physiological patterns of NREM sleep. RMTD and mu rhythm may be observed during NREM and REM sleep.