Screening of olfactory function with a four-minute odor identification test: reliability, normative data, and investigations in patients with olfactory loss.

The study aimed to create a screening test on the basis of the odor identification test as used in the "Sniffin' Sticks" olfactory test kit. It should appeal to the practitioner in terms of 1) time required for testing, 2) reliability, 3) separation of "normal" from "abnormal," and 4) the fact that it allows lateralized screening. Experiments should provide a normative database (number of subjects > 1,000), establish test-retest reliability (n > 100), and compare results from patients with olfactory loss (n > 200). The correlation between results on 2 repetitive tests was .78. The test differentiated anosmics, hyposmics, and normosmics (p < .001). None of the 112 anosmics reached a score higher than 8; the 90th percentile was at a score of 6. When only 6 odors were used for calculating scores, for anosmics the 95th percentile was at a score of 4. These data provide a basis for the screening of patients by means of "Sniffin' Sticks."

[Gustatory olfactory function test with the Güttich technique: an evaluation of the clinical value]. / Der gustatorische Riechtest in der Technik nach Güttich: Eine Uberprüfung der klinischen Wertigkeit.

BACKGROUND: Testing of retronasal olfactory sensitivity is routinely performed in many ENT-departments in German speaking countries. One of the most popular tests relates to an anecdotal report by Güttich [1]. In this test, liquids are placed on the patient's tongue; the patient is then asked to describe the aroma. Assuming that anosmic patients should not use other descriptors than "sweet," "sour," "salty," and "bitter", this test design is frequently applied in disability compensation settings. Surprisingly though, so far there are no studies regarding the sensitivity or specificity of this test in terms of the differentiation between hyposmic and anosmic patients. METHODS: The present investigation was performed in 50 anosmics, 42 hyposmics, and 13 normosmics. The diagnosis "hyposmia" or "anosmia" was based on 1. the patients' history, 2. psychophysical tests using an established test of olfactory function, the "Sniffin' Sticks," and 3. the recording of olfactory evoked potentials. RESULTS: We obtained the following major results: 1. In comparison to hyposmis and normosmics, anosmic patients had greater difficulty identifying the aromas. However, correct identification was not always possible for normosmics. 2. Regarding the differentiation between anosmic and hyposmic patients, the test's sensitivity was 86% with a specificity of 62%. This clearly limits routine clinical application of this test. CONCLUSIONS: Retronasal testing appears to be an elegant and simple means in order to screen olfactory function. However, the presently investigated approach is limited with regard to the discrimination between anosmic and hyposmic patients.