[Comparison of two different methods for measuring interoception of obstructions in asthma patients]

For measuring the interoception of airway resistance, bronchial obstructions are often simulated by flow-resistive loads applied externally (i.e. outside the body) into the respiratory flow. However, it is open to doubt whether interoception characteristics obtained in this manner are really related to the clinical pattern of complaints of asthmatic patients. Possibly such externally applied resistance simulates merely an aspect of the physics of apnoea but not a clinical and hence also psychological aspect of the same. To estimate the significance of these aspects for the perception of obstructions, this ability was measured in 25 asthmatic patients first by means of external added loads; this test was then repeated by noting the subjective assessment of bronchial obstructions caused during a routine histamine provocation test. Both interoception parameters correlated only slightly (rxy = 0.31) which is discussed as a pointer to the assumption that, among other parameters, psychological factors may considerably modify the perception of flow resistivity. No correlations were seen between the characteristic interoception value obtained by means of mesh resistivities and the different variables of the clinical pattern of symptoms. On the other hand, the interoception parameter measured on the basis of bronchial obstructions revealed significant connections with several clinical variables: the greatly increased incidence of respiratory distress at night or during certain external conditions, coping medication, physical exercise and style. It is concluded that only such parameters of perception of obstructions are clinically relevant for patients suffering from asthma, which consider not only the somaticophysical but also the psychic component of asthmatic respiratory distress.