Patients with neuromuscular disorders and thoracic deformations develop alveolar hypoventilation during their disease progression. At that time, non-invasive ventilation(NIV) can be started as treatment.~Fatigue and daytime sleepiness are typical symptoms of alveolar hypoventilation. NIV has the intention to improve these symptoms but no research has been performed whether these improvements also objectively improve physical activity. Further on, no research has been performed on muscle strength and muscle fatigue.~Patients' physical activity, physical capacity and sleep quality will be measured before NIV initiation, after 3 months and 1 year of NIV use.~To start NIV, patients will be admitted to our sleep laboratory for 5 days/4 nights. Polysomnography will be used during NIV titration.~Physical activity will each time be measured by 2 activity monitors during 5 days.
As fatigue and daytime sleepiness are typical symptoms of alveolar hypoventilation in patients with neuromuscular disorders and thoracic deformations, we hope, by starting non-invasive ventilation and improving these symptoms, to increase their physical activity.