The Candy Smell Test in Clinical Routine

Abstract

The "Candy Smell Test" (CST) has been introduced as a new testing method for the evaluation of the human sense of smell. In contrast to other established orthonasal smell tests, the CST addresses the retronasal application of odors, typical for food aroma effects during mastication and swallowing. The aim of this study was to evaluate the CST in a clinical setting in patients with olfactory dysfunction and normal controls against the Sniffin' Sticks test. Furthermore, cutoff points for normal and pathological results in the CST should be determined. The olfactory performance of 96 patients presenting with olfactory disorders and 71 healthy controls was evaluated with the CST-comprised of 23 different aromatized smell candies and the extended Sniffin' Sticks test (threshold, discrimination, and identification). The control group was gender matched but included also younger persons. The tested subjects could easily understand the procedures and were motivated to participate. The CST correlated well with the Sniffin' Sticks for all tested subjects and for patients (n = 96) and controls (n = 71). The proposed cutoff value to differentiate normosmia from hyposmia in the CST was a score of <16 (i.e., 16 correctly identified odors) of 23. A score below 13 in the CST was the cutoff value for anosmia. The CST is an easy-to-handle reliable tool to investigate retronasal olfaction suited for clinical determination of normosmia, hyposmia, and ansomia. In addition, it can be used for investigation where self-application is necessary such as in large survey studies.