Myotonic dystrophy type 1 is a myopathy with complex respiratory pattern and at risk to develop respiratory failure. Classical mode of ventilation are sometimes not tolerated or ineffective in this population. New modes of nocturnal ventilation by combining both volumetric and barometric advantages. The aim of this study is to compare effect of AVAPS mode to bilevel pressure support.

Justification of study

Respiratory abnormalities are complex in Myotonic dystrophy type 1. Some patients presented with isolated alveolar hypoventilation and breathe rhythm irregularity. Nocturnal ventilation is usually proposed but usual modes of ventilation can't provide enough respiratory assistance for patients especially during REM sleep or too much respiratory assistance increasing the risk of asynchrony. The goal of this study is to evaluate the effect of the mode AVAPS (a mode permitting a pressure support with guaranteed volume and offering advantage of volume and pressure support with Bipap A30 Phillips Respironics) compared to bilevel pressure support.

Main Objective To evaluate efficacy of AVAPS Mode at day 7 on arterial PCO2 under ventilation after launching ventilation.

Secondary Objectives To evaluate efficacy of AVAPS Mode at day 90 on daytime arterial PCO2 after launching ventilation.

To evaluate compliance to ventilation at day 7 and 90. To evaluate clinical efficacy on respiratory symptoms, dyspnea and sleepiness at day 1 and 90.

To evaluate quality of life at day 1 and 90. To evaluate effect of AVAPS on polysomnography, nocturnal SaO2, nocturnal PtCO2.

To evaluate Multiple sleep latency and Maintenance of wakefulness tests at day 90.

To evaluate effect of AVAPS on respiratory parameters VC and mouth maximal pressures.

Type of study: Prospective, monocentre, randomized, controlled single blind study on 2 parallel group.

Number of subjects: 32 patients recruited in home ventilation unit of Raymond Poincaré hospital.

Selection criteria : Patients with Myotonic dystrophy presenting at least one clinical signs : effort or rest dyspnea, orthopnea, sleepiness, morning headache or VC<50% or Pi max< 60 cm H2O or time of SaO2<90% more than 5 minutes and Hypercapnia > 6.0 kPa.

Study process Preceding screening period within the 3 months before inclusion. Day 1 to day 3 baseline evaluation. Day 3 Inclusion and Randomisation Day 3 to 8 Launch of ventilation Day 8 Home discharge Day 90 Evaluation of efficacy (secondary objectives) and observance.

Duration Participation of a patient 3 months. Period of inclusion 24 months. Total duration of study 30 months.

Inclusion Criteria:

• Men or women aged > 18 years
• Written consent
• DM1 myotonic dystrophy
• One clinical signs dyspnea rest/effort, orthopnea, daytime sleepiness (Epworth> 10), morning headache.

Or restrictive syndrome: VC< 50 % or Pi max <60 cm H2O Or time of nocturnal saturation < 90 %, > 5 minutes. AND Hypercapnia > 6.0 kPa Pregnancy test negative or use of contraception for women in age of procreation

Exclusion Criteria:

• Patient using previously home ventilation within the 6 months before entering the study
• Patient denying home ventilation
• Refusal to sign consent
• impossibility to be followed during 3 months
• Impossibility to apply ventilation at home
• No social/health coverage
• Patient under tutelage