Objectives: To test symptom perception in asthma under
natural circumstances and to establish relationships between changes in
airway obstruction as indicated by wheeze, dyspnea, general sensations,
and emotional state.
Design: Continuous in
Method: Symptom perception was
tested in 30 adolescents with severe, unstable asthma. They were
continuously monitored in their homes for 72 h. Symptom perception
was defined as the relation between self-reported dyspnea and airway
obstruction as evident from audible wheeze. Tracheal sounds were
continuously recorded with wireless telemetry for wheeze assessment.
Dyspnea was assessed four times per day on a Likert-type 10-point
scale, as well as four times randomly after pager remote command. The
subjects kept records of use of medication, daily activities, general
symptoms, and mood state in a diary.
were nine subjects with one or two wheeze episodes, another three
subjects with three or four episodes, and one subject with almost
continuous wheeze. The presence of wheeze in general related
significantly to a rise (from individual baseline) in dyspnea of>
2.5 scale points. Acute wheeze was the best predictor of a rise in
dyspnea, but prolonged wheeze correlated significantly with negative
mood and general symptoms.
Conclusion: Patients with
prolonged airway obstruction perceived symptoms less well and were more
vulnerable to negative effects of asthma than patients with acute onset