Diagnostic Approach with Quantitative Analysis of Polysomnography in REM Sleep Behavior Disorder

Abstract

Received October 25, 2012 Revised December 20, 2012 Accepted December 20, 2012 Address for correspondence Kee Hyung Park, MD, PhD Department of Neurology, Gachon University, Gil Medical Center, 1198 Guwol-dong, Namdong-gu, Incheon 405-760, Korea Tel: +82-32-460-3346 Fax: +82-32-460-3344 E-mail: khpark@gachon.ac.kr Objectives: Rapid eye movement sleep behavior disorder (RBD) is characterized by the intermittent absence of electromyogram (EMG) atonia during rapid eye movement (REM) sleep and the increase of motor activity associated with dream mentation. However, ICSD-2 criteria did not suggest validated diagnostic criteria and previous studies had no consistency with value ranged 10-20% of REM sleep without atonia (RSWA) in polysomnography (PSG). We investigated standard value about RSWA of Korean RBD patients. Methods: Thirty one patients diagnosed with RBD and 31 normal ageand sex-matched controls were selected. All RBD patients and normal controls were studied using PSG from 2007 to 2012. ICSD-2 criteria was used to select RBD patients and RSWA. We defined RSWA as increasing amplitude by 4 times that of baseline EMG and occupying at least 50% of each epoch or five 3 second mini-epochs. Results: PSG findings showed increased N1 sleep, periodic leg movement index and decreased N2 sleep in RBD patients compared to normal controls. Mean RSWA was 19.21% [±9.93, standard deviation (SD)], with a range of 5.21-38.22% in RBD patients, whereas the mean RSWA in normal control was 0.43% (±0.74, SD) with a range of 0-2.3%. Conclusions: We quantitatively figured out the characteristics of PSG and RSWA in Korean RBD patients. The outcome shows definite differences between RBD patients and normal controls. This study suggest that we may diagnose RBD who have RSWA over 5% of the REM sleep periods. J Korean Sleep Res Soc 2012;9:46-51