Identifying normosmics: a comparison of two populations.

An olfactory function test developed by the Connecticut Chemosensory Clinical Research Center (CCCRC) was administered to 65 normal subjects to determine its ability to identify normosmic subjects. The CCCRC test categorizes individuals into five distinct levels of olfactory functioning according to composite score ranges derived from odor identification and butanol threshold subtests. These categories are: normosmic (normal); mildly, moderately, and severely hyposmic (impaired functioning); and anosmic (no sensation). Comparing score distributions from CCCRC with ours revealed that a greater percentage of our subjects were categorized as hyposmic because of higher butanol thresholds. The butanol threshold subtest was studied further to determine test-retest reliability and normal day-to-day variability in scores. Norms are the basis for interpreting test scores and are important in diagnosing and treating smell disorders.