Abstract: A face mask having a perimeter for sealing against the face of a user is incorporated in a continuous positive airway pressure mask (CPAP) for treatment of central and obstructive sleep disorders. An elongate flexible pneumatic cushion seal is formed around the perimeter of the mask. An air passageway is coupled to the pneumatic air cushion. An inflatable expandable balloon chamber is coupled in open communication through the air passageway to the elongate pneumatic cushion seal. The balloon chamber is inflated to a desired pressure for passage of air between the pneumatic cushion seal and the expandable balloon chamber at said pressure. The pneumatic cushion seal is maintained against the face of a user and follows the changing contours of a user's face by passage of air between the pneumatic cushion seal and the expandable balloon chamber at the desired pressure. This changing volume of air in the pneumatic cushion seal assures that the seal is maintained.