Candidate odours for a short form odorant identification test

Abstract

Measurement of olfactory function is difficult and despite the availability of validated olfactory tests these are not in common use in general clinical practice. The mismatch between self-reported olfactory function and objective test response is well known, thus the need for adequate assessment of olfaction is not disputed. We aimed to determine which if any odour in a commercially available olfactory test could be identified by 70 % or more of normal subjects with a view to developing a shortened screening test for use in general otolaryngology and non-specialist clinics in the United Kingdom. Hospital staff and medical students, under 50 years of age were recruited. The tests were undertaken in a quiet room of neutral odour. Subjects were asked to self-identify 12 odorants presented consecutively and to record how strongly they perceived the odorants on a 4-point scale. One hundred and four participants correctly identified the odorant in 466 (37.3 %) of the 1,248 individual odorant identification tests. Peppermint, fish and coffee odours were identified by 88.5, 79.8 and 69.7 % of participants, respectively, without the advantage of a choice of name prompt. These supra-threshold test odour stimuli were perceived as present in all of the individual odour identification tests, but correct identification of the test odour was very much lower for the other nine test stimuli. Peppermint, fish and coffee are odours that should be evaluated further for inclusion in a short form olfactory identification test in a British population.