Realization of a double biofeedback to control breathing activity.

A devise giving a double respiratory movements biofeedback signal has been build. The transducers are two mercury strain gauge, giving a linear electrical resistance change with length variations; they can be applied to the thorax and abdomen by belts, or simply fixed to any two parts of the thorax. The electrical signals are converted in acoustical signals: one like an air blow, the other like a siren: the frequencies of the signals are proportional to the movements amplitude: as a result the patient is informed simultaneously of the respiratory movements of two different sites and can easily control the relative amplitude.