Abstract: In combination with an air mattress, the pressure within which is to be controlled, a first switch for actuation at a first air pressure and a second switch for actuation at a second air pressure higher than the first. The difference between the first and second air pressures defines a zone within which the air pressure in the mattress is not controlled. The first and second switches have air inlets. A source of compressed air has an outlet. An electrically actuated air valve has an air inlet and an air outlet. The first and second switches are coupled across a source of electrical power for controlling the supply of compressed air from the compressed air source to the mattress and exhausting compressed air from the mattress, respectively.

Abstract: A method for simulating speech in a tracheotomized individual includes providing a source of compressed air, regulating the air pressure, and controlling the flow of air from the source between a condition in which airflow is stopped and a condition in which airflow is allowed in response to actuation by the individual. The air flow is supplied to a reed to vibrate it, and the resulting vibration-modulated air flow is introduced into the pharynx of the individual, permitting the individual to articulate audibly comprehensible speech. Apparatus for carrying out this method is also described.