A single session of Mechanical Insufflation-Exsufflation (with Cough AssistÒ) may improve airway flow and gas exchange in neuromuscular atrophy patients. The goal of this study is to confirm the beneficial effects of this treatment in a larger neuromuscular population, to study its mechanisms of action and to assess whether the effects observed persist over time. A better knowledge of this treatment should help to define its position in the respiratory management of neuromuscular patients.

30 SMA and DMD adult patients will be recruited in the home ventilation unit of the intensive care department of Raymond Poincaré Hospital (Assistance Publique-Hôpitaux de Paris,Garches, France).

Respiratory parameters and comfort will be evaluated before and after (5min,

1h, 3h) a MI-E session. Vital capacity, maximal inspiratory and expiratory pressures (PImax and PEmax), peak cough flow and peak expiratory flows will be measured. Breathing pattern will be recorded allowing the measurements of respiratory frequency, tidal volume, Inspiratory time (Ti),total breath (Ttot) during tidal breathing and the calculation of tension-time index (TT0.1).

Gas exchange will be evaluated by measuring end tidal CO2, transcutaneous CO2 and pulse oxymetry.

Respiratory comfort will be assessed with a visual analog scale. Optoelectronic plethysmography will be use to perform regional ventilation evaluation. Using chest wall motion analysis we will compute respiratory participation of upper, lower thorax and abdomen, right and left side.

Results should allow to analyse the effects of MI-E on regional ventilation. The mechanisms of action of MI-E on respiration and chest-wall motion will be analysed and the persistence of the beneficial effect of MI-E will be assessed.

Inclusion Criteria:

• Adults aged more than 18 years
• Written consents
• Neuromuscular disorders
• Hemodynamic stability

Exclusion Criteria:

• Pulmonary disorder
• Acute respiratory failure
• Cognitive deficit