Respiratory resistance feedback in the treatment of bronchial asthma in adults.

Two studies evaluated feedback of total respiratory resistance of the airways (TRR) as a treatment for adults with moderate to severe chronic bronchial asthma. Respiratory function tests and questionnaires were used to select the patients and to assess treatment effects. Study I provided eight biofeedback sessions in four weeks (each session containing four, 3-min training trials) plus three pre-treatment and three post-treatment sessions. Over the eight treatment sessions biofeedback failed to produce any significant improvements, although overall the nine patients showed lower mean initial TRR values at the three post-treatment sessions compared with the three pre-treatment sessions. Patients consistently showed improvement following bronchodilator administration at the end of every session. In study II, biofeedback was provided in one intensive session of 20, 2-min trials. While careful instruction about biofeedback was provided to subjects, and more post-treatment measures were included, no significant improvements were shown following biofeedback, but were shown following bronchodilator administration.