Breathlessness is an important symptom of respiratory disease and its quantification is useful, especially during exercise testing. However, measures of perceived breathlessness are not readily understood by children and are somewhat subjective. We studied an objective score: the 15-count breathlessness score, in which subjects take a deep breath and then count out loud to 15; the number of breaths taken to complete the count is the score. Fifty-four children with cystic fibrosis (CF) performed a standard 6-min walk and 3-min step test (30 steps/min for 3 min). The 15-count score was compared with the modified Borg scale after exercise. A further 45 children with CF and 33 healthy schoolchildren underwent an incremental step test (20, 30, and then 40 steps/min for 2 min each), using the 15-count score, then the Borg scale, and then a standard visual analogue score between increments. The 15-count score was significantly increased after both the walk and the step test (P < 0.0001), although the step test made children significantly more breathless than the walk test (P < 0.0001). At baseline, there were no differences in any of the breathlessness scores between the CF and normal children. After the full 6 min of the incremental step test, CF children were significantly more breathless than the normal children, as measured by 15-count (P < 0.0001), Borg (P < 0.0005), and visual analogue scores (P < 0.0005). All scores increased significantly as exercise intensity increased over time, but the slope estimates were significantly greater for CF patients than for normal children (P < 0.0005). The 15-count score has been evaluated as an objective measure of breathlessness. It is easy to explain and perform, and can be used by any child capable of counting fluently to 15 in any language. It is best used in conjunction with a subjective score, and either the Borg scale or a visual analogue score is appropriate.
Copyright 2000 Wiley-Liss, Inc.