The Capacity of Children with and Without Asthma to Detect External Resistive Loads on Breathing

Clinical observations and research with adults consistently showed that subjective symptoms of asthma poorly reflect actual airway obstruction. The lack of accurate symptom perception poses a problem for medication and management of asthma. The accuracy of airflow detection was studied in 46 children with and 46 without asthma (aged 7-18 years). They breathed through a facemask and responded to load stimuli of different intensity. Sessions consisted of 10 blocks of 5 min, each with 10 stimuli presented. Experiment 1: Loads of increasing intensity presented to 36 children with and 36 without asthma. Seven asthmatics had a reliable detection threshold (just noticeable difference, jnd) analogous to 64% fall in forced expiratory volume in 1 sec (FEV1). Ten normal controls had a jnd of 39% fall. Experiment 2: Loads randomly presented to 10 children with and 10 without asthma. Four asthmatics had a jnd of 64% fall in FEV1. Six normal controls had a jnd of 39% fall. The results demonstrated that children generally were poorly perceiving load stimuli and that asthmatics were less accurate.