Symptoms of blood pressure dysregulation, impaired swallowing and digestion are common amongst parkinson patients. The overall aim of this study is to examine blood pressure regulation and esophageal motility and gastric emptying in Parkinson's disease (PD) patients.

The investigators hypothesize that - compared to age-matched controls - PD patients display an altered regulation of blood pressure, altered gastroesophageal motility, and delayed gastric emptying. These symptoms occur already early in the disease process, but aggravate with progression of the disease.

The investigators will perform a 7-day blood pressure measurement, measurement of central blood pressure and pulse wave velocity, assessment of pulse variability, Schellong tests to assess orthostatic function, high resolution manometry assessments during swallowing acts, and a 13C-sodium octanoate breath test to assess gastric emptying, in 18 PD patients (9 each Hoehn&Yahr stages 1,2) and 12 age- and gender-matched healthy controls. Results will be interpreted in relation to the severity of PD motor symptoms.

The investigators anticipate that blood pressure dysregulation and gastroesophageal motility disturbances will be present only in PD subjects, but not in matched controls without neurological disorders and without any extrapyramidal motor signs. Furthermore, the investigators expect to find an association between motor impairment and the severity of these autonomic symptoms, however, that according to the Braak staging, subtle disturbances must already be present in the early stages of PD.

Inclusion criteria: - informed, written & formal consent for participation

• male/female subjects, aged 50-70 years
• PD patients (9 subjects each in Hoehn & Yahr stage 1 & 2)

Exclusion criteria: - Antihypertensive treatment

• medication influencing gastrointestinal motility for at least the elimination half life of the drug
• medication interfering with blood-pressure regulation for at least the elimination half life of the drug
• significant systemic illness
• BMI < 18 or > 30kg/m2
• symptoms or a history of GI disease or surgery
• with any evidence of infectious disease
• evidence or history of drug or alcohol abuse
• diabetes mellitus

Subjects included in this trial must fulfil the he following criteria:

• informed, written & formal consent for participation

• male / female subjects, aged 50-70 years

  18 PD patients

• 9 subjects Hoehn & Yahr stage 1, disease duration <4 years

• 9 subjects Hoehn & Yahr stage 2; disease duration 4-8 years

  12 healthy control subjects

• age- and gender-matched

• without signs or history of neurological disorders

• without significant systemic comorbidities (malignant / cardiovascular)