Interviewer-administered rating of severity of dyspnea at a single state. The BDI provides a multidimensional measurement of dyspnea based on 3 components that evoke dyspnea in activities of daily living, in symptomatic individuals. TDI measures changes in dyspnea severity from the baseline as established by the BDI. Rated in five grades from 0 (very severe) to 4 (no impairment) for each category. Consists of 24 items. Scoring for each item ranges from 0 (very severe) to 4 (no impairment);Three additional options in each category, which do not contribute to the scoring, allow circumstances in which dyspnea cannot be rated. A self-administered computerized version has been validated with performance comparable to the interviewer-administred instrument