Patients with Parkinson's disease (PD) frequently experience upper gastrointestinal disorders. During the disease, weight loss is often noticed. Recently, many studies have demonstrated that STN-DBS improved extrapyramidal symptoms. Interestingly, PD patients gain weight after STN-DBS, at least in part due to a decrease in resting energy expenditure.

Purpose: To evaluate benefits of STN-DBS on upper gastrointestinal symptoms and motility.

Patients et method: PD patients waiting for STN-DBS, will be assessed in a preoperative time (2 times at, at least, 3 month intervals, to evaluate the natural history of the disease on upper gastrointestinal symptoms and motility) and in a postoperative time, after 6 months of chronic STN-DBS. Each assessment will include : 1/ questionnaires about frequency and severity of upper gastrointestinal symptoms; 2/ a nutritional assessment (body mass index, dietary assessment); 3/ the gastric emptying measurement with the 13C-octanoic acid breath test; 4/ the colorectal transit time measurement with radio-opaque markers 5/ an indirect calorimetry to estimate resting energy expenditure; 6/ and plasmatic leptin and ghrelin concentrations, hormones involved in the homeostatic regulation of appetite.

Perspectives: This physiopathological study should allow us to understand the mechanisms of the effects of STN-DBS on upper gastrointestinal symptoms and weight regulation in PD patients.

Inclusion Criteria:

• Parkinson's disease
• Electrode implantation for deep brain stimulation in progress
• Age <70 yr
• Motor fluctuations and dyskinesias
• Motor symptoms improvement with L-dopa > 50%
• No dementia
• No depression
• No major psychiatric symptom
• Normal brain MRI

Exclusion Criteria:

• Contra-indication of neurosurgery
• Pregnancy
• Diabetes
• Obesity
• Compulsive eating disorders
• Organic digestive disease
• Gastrointestinal resection
• Prokinetic treatment
• Coagulopathy