Rapid Eye Movements during REM Sleep Differentiate PSP from Parkinson's Disease.

ABSTRACT

BACKGROUND: Little is known about the characteristics and occurrence frequencies of rapid eye movements (REMs) during REM sleep in movement disorders. OBJECTIVES: The aim of this study was to detect and characterize REMs during polysomnographically defined REM sleep as recorded by electro-oculography (EOG) in 12 patients with progressive supranuclear palsy (PSP), 13 patients with Parkinson's disease (PD) and 12 healthy controls. METHODS: Using a modified EOG montage, we developed an algorithm that automatically detects and characterizes REMs during REM sleep based on their presumptive saccadic kinematics. RESULTS: Compared to PD and healthy controls, REM densities and REM peak velocities were significantly reduced in PSP. These effects were most pronounced in vertical REMs. CONCLUSION: Ocular motor dysfunction, one of the cardinal features of PSP, seems to be equally at play during REM sleep and wakefulness. For future studies, we provide a novel tool for the unbiased analysis of REMs during REM sleep in movement disorders.