The main aim of this study is therefore to evaluate the impact of Prader Willi Syndrome (PWS) on lung and thoracoabdominal volumes, respiratory muscle strength and awake ventilatory pattern, and to quantify and localize the PWS-induced respiratory restriction.

The aim is to study lung function in obese PWS patients using both volitional (spirometry, nitrogen wash-out, and maximal pressure measurements (MIP and MEP)) and non-volitional (awake ventilatory pattern by opto-electron plethysmography) tests, both in sitting and supine positions.

Spirometry, nitrogen wash-out, and MIP and MEP measurements are comprehensive assessments, while optoelectronic plethysmography allows restriction location through accurate measurement of thoracoabdominal volumes.

The results of the study could provide useful information about the calculation of the volumes enclosed by the grid of markers (in particular, the volume of the rib cage, which reflects the action of the intercostal muscles, the volume of the abdomen, which reflects the action of the diaphragm in the inspiratory phase and of the abdominal muscles during exhalation and their sum, which represents the total variation of the thoraco-abdominal wall. All these finds could be useful for respiratory rehabilitation protocols for obese PWS patients.

Patients with Prader Willi Syndrome

Inclusion Criteria:

• Age 20-50 years
• Prader Willi Syndrome
• Body Mass Index > 30 kg/m2

Exclusion Criteria:

• Lack of signed consent form

Control subjects

Inclusion Criteria:

• Age 20-50 years
• Body Mass Index < 25 kg/m2

Exclusion Criteria:

• Lack of signed consent form

Patients with Prader Willi Syndrome and obesity