Mechanical ventilation is one of the only treatment that has improved survival of patients with neuromuscular respiratory failure. As disease progresses, some patients may require longer ventilation period. Non invasive mechanical ventilation is the preferred method of ventilation but it may interfere with speech and communication of patients who require ventilation throughout the day. The investigators are evaluating the effect on speech and communication of a ventilation device which allows patients to momentarily and voluntarily withhold ventilation if they want to speak. This should allow the patients to have a more fluid speech.

Inclusion Criteria:

• Patient with restrictive respiratory failure secondary to a neuromuscular disorder, without any bulbar involvement.
• Age greater than or equal to 18.
• Hospitalization in Home Ventilation Unit of the intensive care department of R. Poincaré Hospital.
• Non invasive mechanical ventilation for a duration equal or above 14h per day.
• Patient in a steady state at the time of the study
• written informed consent

Exclusion Criteria:

• patient's refusal to participate to the study
• Inability to read the selected text
• Inability to use the ventilator switch
• Inability to cooperate
• Hemodynamic instability
• Acute respiratory failure
• No affiliation to social security