Motor Control During Rapid Eye Movement (REM) Sleep Behaviour Disorder

Subthalamic Nuclei (STN) Local Field Potentials to Investigate Motor Control During REM Sleep Behaviour Disorder (TCSP) Secondary to Idiopathic Parkinsons Disease (PD)

To compare the electrical activity of SubThalamic Nuclei (STN), by mean of local field potentials recordings, during the phasic behaviours of RBD with the electrical activity recorded at this level during the execution of voluntary movements during the "off" and the "on" phases in patients with RBD secondary to PD.

Patient with severe Parkinson's disease (PD) with motor fluctuations are akinetic and bradykinetic during the "off" phases. Their motor status dramatically improves during "on" phases, due to the effect of dopaminergic agents.

In the off phases, the plasmatic levels of dopaminergic drugs are the lowest. The plasmatic levels of dopaminergic drugs are also very low during nocturnal sleep.

Nevertheless, PD patients may show vigorous and rapid movements during REM Behaviour Disorder (RBD). Thirty-three to 46% of the patients with PD have RBD.

Akinesia and bradykinesia are the consequence of a hyperactivity of the SubThalamic Nuclei (STN). The electrophysiological correlate of this hyperactivity causing akinesia and bradykinesia is represented by STN beta activity, recorded by local field potentials.

STN beta activity is not present during the execution of a voluntary movement at an "on" phase. Levodopa therapy, which can revert akinesia and bradykinesia, also suppress STN beta activity in PD patients The STN is the surgical target for Deep Brain Stimulation (DBS) of the basal ganglia to improve the motor symptoms of PD.

The STN has bilateral connections with the laterodorsal nucleus/pedunculopontine tegmentum (LDT/PPN), a key structure for REM sleep regulation.

The investigators hypothesize that during the execution of the phasic motor behaviours of RBD the pattern of discharge of STN differs from the one observed during voluntary movements in the "off" phase, in PD patients. In other terms, we expect the STN beta activity to disappear during the execution of phasic motor behaviors of RBD.

Inclusion Criteria:

• Men and women, 35 to 70 years old, with idiopathic PD (UKPDSBB criteria) with motor fluctuations
• having RBD according to the International Classification of Sleep Disorders, 2nd edition (ICSD-2) criteria
• Eligible to neurosurgical treatment of PD by implantation of intracranial electrodes for the DBS of STN
• Giving a written informed consent
• Affiliated to the French social security program

Exclusion Criteria:

• Atypical or secondary parkinsonian syndrome
• Cognitive impairment which may compromise the understanding and patient's participation to the protocol (Mattis dementia rating scale score ≥ 136)
• Patient under guardianship, trusteeship or judicial protection
• Pregnancy or breastfeeding
• Patient participating to another clinical research study in the same period