Multicenter investigation of 1,036 subjects using a standardized method for the assessment of olfactory function combining tests of odor identification, odor discrimination, and olfactory thresholds

"Sniffin' Sticks" is a test of nasal chemosensory performance that is based on penlike odor-dispensing devices. It is comprised of three tests of olfa ctory function: tests for odor threshold, discrimination and identification . Previous work has already established its test-retest reliability and val idity in comparison to established measures of olfactory sensitivity. The r esults of this test are presented as a composite TDI score - i.e., the sum of results obtained for threshold, discrimination and identification measur es. The present multicenter investigation aimed at providing normative valu es in relation to different age groups. To this end, 966 patients were inve stigated in 11 centers. An additional study tried to establish values for t he identification of anosmic patients, with 70 anosmics investigated in fiv e specialized centers where the presence of anosmia was confirmed by means of olfactory evoked potentials. For healthy subjects, the TDT score at the 10th percentile was 24.5 in subjects younger than 15 years, 30.3 for ages f rom 16 to 35 years, 28.8 for ages from 36 to 55 years and 27.5 for subjects older than 55 years. While these data can be used to estimate individual o lfactory abilities in relation to a subject's age, hy posmia was defined as the 10th percentile score of 16- to 35-year-old subjects. Our latter study revealed that none of 70 anosmics reached a TDI score higher than 15. This score of 15 is regarded as the cut-off value for functional anosmia. These results provide the basis for the routine clinical evaluation of patients with olfactory disorders using "Sniffin' Sticks."