PERCEPTION SCORING OF INDUCED BRONCHOCONSTRICTION AS AN INDEX OF AWARENESS OF ASTHMA SYMPTOMS

Perception of asthma symptoms shows a wide interindividual variability. Poor perception of airflow obstruction may lead to undertreatment of asthma. We reviewed the possibility of using a simple test to detect poor perceivers of bronchoconstriction as part of the investigation of asthmat. We studied 150 consecutive subjects referred for assessment of airway responsiveness. All had a histamine PC20 within the asthmatic range (<16 mg/ml) and a fall in FEV(1) of <20 percent after saline inhalation. On histamine challenge, before each FEV(1) measurement, perception of dyspnea was assessed on a modified Borg scale. A perception score of breathlessness at 20 percent fall in FEV(1)(PS20) was obtained by interpolation of the two last points on the perception/fall in FEV(1) curve. It was concluded that in a hyperreactive population, PS20 (1) showed a normal distribution pattern; (2) was similar in both genders; and (3) increased with age due to high postcontrol saline inhalation scores. Hypoperceivers or hyperperceivers were similar for age, sea, baseline FEV(1), and PC20. The PS20 determination may be a useful additional parameter to obtain during provocation tests to assess perception of symptoms associated with bronchoconstriction. Its correlation with clinical outcome remains, however, to be determined.