THE INFLUENCE OF EXTERNAL STIMULATION ON AIR-FLOW DETECTION BY CHILDREN WITH ASTHMA

The relevance and significance of the concept of a 'competition of cue s' for the understanding of symptom perception in childhood asthma was investigated during detection of externally applied resistive loads o n breathing. The concept predicts that subjects would respond less fre quently and less accurately during external stimulation. The sample co nsisted of 36 children with and 36 without asthma, aged 7-18 years. De tection of airflow was measured in a neutral and in an external stimul ation condition. The children breathed through a facemask and responde d to changes in airflow by pressing a button. The stimulus presented a nd withdrawn was analogous to a decrease in lung function (Forced Expi ratory Volume in one second) of approximate to 39%. Accuracy of detect ion of airflow was defined as correct minus false positive responses t o load stimuli. The results showed that children with and without asth ma responded significantly less frequently during external stimulation than in the neutral condition. However, the accuracy of detection amo ng non-asthmatics was not affected by external stimulation. Children w ith asthma responded significantly more accurately during external sti mulation. The results are discussed in the light of children's accurac y to perceive actual airways obstruction.