A comparison of the reproducibility and the sensitivity to change of visual analogue scales, Borg scales, and Likert scales in normal subjects duringsubmaximal exercise

Objective: To assess which subjective scale, the visual analogue scale (VAS ), the Borg CR10 (Borg) scale, or the Likert scale (LS), if any, is decided ly more reproducible and sensitive to change in the assessment of symptoms. Design: Prospective clinical study. Setting: Exercise laboratory. Participants: Twenty-three physically active male subjects (mean +/- SD age of 30 +/- 4 years old) were recruited. Intervention: Each subject attended the exercise laboratory on four occasio ns at intervals of 1 week. Three subjective scales were used: (1) the VAS ( continuous scale); (2) the Borg scale (12 fixed points); and (3) the Likert scale (LS; 5 fixed points). Four identical submaximal tests were given (2 min at 60% maximum oxygen uptake [(V)over dot O(2)max] and 6 min at 70% (V) over dot O(2)max). Two tests were undertaken to assess the reproducibility of scores that were obtained with each subjective scale. Two other tests we re undertaken to assess the sensitivity of each scale to a change in sympto m perception: a double-blind treatment with propranolol, 80 mg, (ie, active therapy; to increase the sensation of breathlessness and general fatigue d uring exercise) or matching placebo. The subjective scale scores were measu red at 1 min 30 s, 5 min 30 s, and 7 min 15 s of exercise. Reproducibility was defined as the proportion of total variance tie, between-subject plus w ithin-subject variance) explained by the between-subject variance given as a percentage. Sensitvity was defined as the effect of the active drug thera py over the variation within subjects. Results: Overall, the VAS performed best in terms of reproducibility for br eathlessness and general fatigue, with reproducibility coefficients as high as 78%. For sensitivity the VAS nas best for breathlessness (ratio, 2.7) a nd the Borg scale was most sensitive for general fatigue (ratio, 3.0). The relationships between the respective psychological and physiologic variable s were reasonably stable throughout the testing procedure, with overall typ ical correlations of 0.73 to 0.82. Conclusion: This study suggests that subjective scales can reproducibility measure symptoms during steady-state exercise and can detect the effect of a drug intervention. The VAS and Borg scales appear to be the best subjecti ve scales for this purpose.