Chronic bilateral subthalamic stimulation leads a spectacular clinical improvement in patients with motor complications. However, the post-operative body weight gain involved may limit the benefits of surgery and induce critical metabolic disorder. The aim of this study to determine the energy expenditure in usual conditions of life.

Patients will be studied before (between 3 and 1 months) and after (1 month) STN-DBS surgery. Each time the same measurements will be taken. The principal ones will be :

• Clinical examination
• Autoevaluation dietary questionnaire
• Biological tests
• Study in calorimetry chamber (only in Clermont-Ferrand centre)
• Heart rate recorded during 7 days in usual conditions of life
• Energy expenditure recorded during 14 days in usual conditions of life with normalized water (18O 10 %) and Deuterium oxide (99.94 %D)
• Acute Ldopa challenge (in both conditions of dopa and stim)
• Apathy evaluation
• Body weight, and body compositions measurements

Inclusion Criteria:

• Aged between 18 and 70 years old
• Diagnosis of Parkinson' disease established for 5 years at least
• Ldopa effect > 50 %
• Hoehn and Yarh score > 2.5 in On phase

Exclusion Criteria:

• Metabolism disorder
• Biological analysis abnormal