Congenital central hypoventilation syndrome (CCHS) is a neuro-respiratory disease characterized by lifethreatening sleep-related hypoventilation involving an alteration of CO2/H+ chemosensitivity. This suggests cortical activity during awakening to maintain breathing. Cortical activity to keep breathing is usually associated with breathing discomfort ; this is the case in healthy subjects under non invasive ventilation (NIV) or with expiratory charge as well as in patients with amyotrophic lateral sclerosis. This can suggest that CCHS may be breathless at rest and this discomfort could be reduced by NIV.

The objective is to evaluate dyspnea with a multi dimensional score, MDP, in CCHS patient at rest in every day life and during 1H session of NIV.

The investigators will perform a prospective, including 20 CCHS patients. MDP scores will be measure before and after 1H-non invasive ventilation as well as a visual scale of 100mm in order to evaluate variation of breathing discomfort before/after NIV.

The investigators expect that CCHS patients don't have rest dyspnea but NIV would improve breathing discomfort that would mean they have latent rest dyspnea.

Inclusion Criteria:

• patients with CCHS confirmed by genetic test
• patients with long term non invasive ventilation
• no recent condition that could impact breathing sensations such as infection, pulmonary embolism, heart failure

Exclusion Criteria:

• pregnancy
• phrenic nerve stimulation

Adults with CCHS who already require long terme NIV but not phrenic nerve stimulation