Smell discrimination and identification scores in Thai adults with normosmia

Abstract

Background: Olfactory function can be assessed using quantitative or qualitative tests. The phenyl ethyl alcohol (PEA) olfactory threshold test is a useful quantitative test by which to detect olfactory thresholds and to classify them into normosmia, hyposmia, and anosmia. Qualitative tests of olfaction include the smell discrimination and identification tests, which are helpful in diagnosing several neurological diseases. Objectives: To identify normal values of smell discrimination and identification scores as references for Thai adults. Methods: We prospectively recruited 128 healthy participants with normosmia as measured by the PEA olfactory threshold test and tested them for smell discrimination and identification scores. Results: The participants included 64 men and 64 women with age ranging from 18 to 60 years and a mean age of 35.9 years. Median score (interquartile range) of smell discrimination was 16 (13.5-16.0) and mean score (± standard deviation) of smell identification was 8 ± 1.5. The ability of women to discriminate and identify smells was significantly better than that of men as shown by a lower olfactory threshold and higher discrimination and identification scores. Conclusions: Our study provides normal values for smell discrimination and identification scores in Thai adults, which may be used as references in clinical practice and research. The ability to identify smells may be influenced by individual experience and cultural backgrounds. Keywords: Normosmia, PEA test, phenyl ethyl alcohol olfactory threshold, smell discrimination test, smell identification test