Interoception of respiratory resistance in asthmatic patients

The interoception of respiratory obstruction was investigated in three different experimental or quasi-experimental studies. In two experiments of the first study, the psychophysics of the perception of externally added flow resistive loads were examined by using a signal detection approach. Asthmatic patients displayed a decreased sensitivity in the discrimination of such loads. The second study assessed the individual consistency of dyspnea ratings at different levels of bronchoconstriction provoked by allergic agents. A great variation in subjects' ability to discriminate consistently between various levels of airway resistance was observed. This ability was found to be relevant for coping with asthma. In the third study the visceral perception hypothesis of J. Brener was examined. This theory states that biofeedback training of voluntary control of respiratory resistance is accompanied by an improvement in perception of airway obstruction. No specific effect on load perception resulted from this training. The results of these three studies are of specific relevance to symptom perception in asthmatic patients. Further experimental studies should be directed towards the interoception of real bronchoconstriction instead of the perception of added loads which only partially models the clinical situation.