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

Abstract

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.

Key Words:

• Airway obstruction
• Asthma
• Children
• External resistive loads
• Signal detection
• Symptom perception