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Parkinson’s Disease
Volume 2014, Article ID 852965, 8 pages
Research Article

Polysomnographic Features of Sleep Disturbances and REM Sleep Behavior Disorder in the Unilateral 6-OHDA Lesioned Hemiparkinsonian Rat

1Department of Neurology, Penn State College of Medicine, Hershey, PA 17033, USA
2Division of Engineering, John Brown University, Siloam Springs, AR 72761, USA
3Department of Psychiatry, Penn State College of Medicine, Hershey, PA 17033, USA
4Penn State Milton S. Hershey Medical Center, Mail Code H109, Room C2846, 500 University Drive, Hershey, PA 17033, USA

Received 27 August 2014; Revised 10 December 2014; Accepted 10 December 2014; Published 25 December 2014

Academic Editor: Antonio Pisani

Copyright © 2014 Quynh Vo et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Sleep pattern disruption, specifically REM sleep behavior disorder (RBD), is a major nonmotor cause of disability in PD. Understanding the pathophysiology of these sleep pattern disturbances is critical to find effective treatments. 24-hour polysomnography (PSG), the gold standard for sleep studies, has never been used to test sleep dysfunction in the standard 6-OHDA lesioned hemiparkinsonian (HP) rat PD model. In this study, we recorded 24-hour PSG from normal and HP rats. Recordings were scored into wake, rapid eye movement (REM), and non-REM (NREM). We then examined EEG to identify REM periods and EMG to check muscle activity during REM. Normal rats showed higher wakefulness (70–80%) during the dark phase and lower wakefulness (20%) during the light phase. HP rats showed 30–50% sleep in both phases, less modulation and synchronization to the light schedule , and more long run lengths of wakefulness . HP rats also had more REM epochs with muscle activity than control rats . Our findings that the sleep architecture in the HP rat resembles that of PD patients demonstrate the value of this model in studying the pathophysiological basis of PD sleep disturbances and preclinical therapeutics for PD related sleep disorders including RBD.