Sleep benefit (SB) is a prominent spontaneous, apparently unpredictable, transitory improvement in motor function reported by around 50% of patients affected by Parkinson's Disease (PD) after sleep and before taking their first dose of dopaminergic medications. The aim of this study is to test the hypothesis that objective and/or subjective improvement of motor function might be due to a carry-over effect of Rapid Eye Movements (REM) sleep at awakening from this sleep phase.

The "Awake & Move" study is the second part of the Sleep, Awake & Move project. This study will be conducted in a subgroup of unselected, consecutive patients having completed the part I of the Sleep, Awake & Move project (i.e. the "Sleep & Move" study). The investigators plan to explore the carry-over effect of REM sleep on motor function in a subgroup of PD subjects p. In this interventional study the investigators expect to induce SB by awakening the subjects from nocturnal REM sleep in a sleep laboratory setting, but not from Non-Rapid Eye Movements (NREM) sleep (control intervention).

Inclusion Criteria:

• Diagnostic criteria of idiopathic Parkinson's disease (UKPDBB)
• Mild to moderate disease (Hoehn & Yahr score ≥ 1 and < 3)
• Mentally and physically capable to give informed consent
• Stable antiparkinsonian and psychotropic therapy for the last 30 days

Exclusion Criteria:

• Atypical parkinsonian syndrome
• Cognitive impairment (MMSE ≥ 26)
• Deep brain stimulation
• History of cerebro-vascular disease, epilepsy, or other disabling neurological diseases
• Psychiatric disorders, excepting mild depression
• Alcohol abuse
• Other clinically significant severe concomitant disease states
• Inability to follow the procedures of the study (e.g. due to language problems, psychological disorders, etc.)
• Participation in another study with investigational drug within the 60 days preceding and during the present project.
• subjects with (a) sleep-disordered breathing [Respiratory Disorder Index (RDI)≥ 5] and (b) with no clear-cut distinction of REM and NREM sleep, based on a video-polysomongraphical recording.

The sleep technician in charge to apply the study intervention was the only person to be aware of the sleep phase the patient was awaken from.