Development and validation of the Dyspnea Index (DI): a severity index for upper airway-related dyspnea

J Voice. 2014 Nov;28(6):775-82. doi: 10.1016/j.jvoice.2013.12.017. Epub 2014 Oct 12.


Objectives: To (1) develop and validate the Dyspnea Index (DI); (2) quantify severity of symptoms in upper airway dyspnea; and (3) validate the DI as an outcome measure.

Study design: Survey development and validation.

Methods: Three hundred sixty-nine participants were recruited for different phases of the study. Two hundred participants with chief complaints of dyspnea were given a 41-item questionnaire addressing common symptoms of dyspnea related to the upper airway. The questions were then reduced based on principal component analysis (PCA) and internal consistency resulting in a 10-item questionnaire. Cognitive interviews were conducted with 15 participants. Test-retest reliability and discriminant validity were measured from 51 participants. The DI was further validated by administering the index to 57 healthy controls (HC). Validation of the DI as a treatment outcome tool occurred with 46 participants' pre- and post-treatment scores.

Results: PCA revealed that only a single factor was being measured in both the original 41- and 10-item questionnaires. Additional cognitive interviewing suggested that no modification was needed to the DI. Test-retest reliability was r = 0.83. Discriminant validity was r = 0.62. The Mann-Whitney test demonstrated significant differences between healthy/symptomatic participants. Scores from the HC cohort resulted in a mean of 3.12 (SEM = 0.484; SD = 3.65) for the normative values.

Conclusions: The DI is an effective and efficient instrument to quantify patients' symptoms of upper airway dyspnea. It is a statistically robust index, with significant reliability and validity, and can be dependably used as a treatment outcome measure.

Keywords: Dyspnea; Glottal stenosis; Laryngeal stenosis; Outcomes; Paradoxical Vocal Fold Motion Disorder (PVFMD); Questionnaire; Shortness of breath; Symptom severity; Vocal Cord Dysfunction (VCD).

Publication types

  • Validation Study

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Cognition
  • Dyspnea / diagnosis*
  • Dyspnea / physiopathology
  • Dyspnea / psychology
  • Dyspnea / therapy
  • Factor Analysis, Statistical
  • Female
  • Humans
  • Interviews as Topic
  • Male
  • Middle Aged
  • Observer Variation
  • Predictive Value of Tests
  • Principal Component Analysis
  • Prognosis
  • Reproducibility of Results
  • Respiration*
  • Respiratory System / physiopathology*
  • Severity of Illness Index
  • Surveys and Questionnaires*
  • Young Adult