The influence of external stimulation on airflow detection by children with asthma

Abstract

The relevance and significance of the concept of a ‘competition of cues’ for the understanding of symptom perception in childhood asthma was investigated during detection of externally applied resistive loads on breathing. The concept predicts that subjects would respond less frequently and less accurately during external stimulation. The sample consisted of 36 children with and 36 without asthma, aged 7-18 years. Detection of airflow was measured in a neutral and in an external stimulation condition. The children breathed through a facemask and responded to changes in airflow by pressing a button. The stimulus presented and withdrawn was analogous to a decrease in lung function (Forced Expiratory Volume in one second) of 39%. Accuracy of detection of airflow was defined as correct minus false positive responses to load stimuli.

The results showed that children with and without asthma responded significantly less frequently during external stimulation than in the neutral condition. However, the accuracy of detection among non-asthmatics was not affected by external stimulation. Children with asthma responded significantly more accurately during external stimulation. The results are discussed in the light of children's accuracy to perceive actual airways obstruction.