The Laryngoscope Lippincott Williams & Wilkins, Inc. © 2006 The American Laryngological, Rhinological and Otological Society, Inc. Clinical Significance of Results from Olfactory Testing Volker Gudziol, MD; Jo ¨rn Lo ¨tsch, PhD; Antje Ha ¨ hner, MD; Thomas Zahnert, PhD; Thomas Hummel, PhD Background: Although widely used in healthy subjects and patients with olfactory loss, the signifi- cance of changes of scores from validated olfactory tests is unknown. Aim and Methods: The aim of the present study was to relate the self-assigned changes of olfactory function in terms of “better,” “un- changed,” and “worse” in patients with smell disor- ders with the results from olfactory testing by means of a validated test set. Olfactory function of 83 anos- mic or hyposmic patients (40 women, 43 men; age 12– 84 yr) was tested on two occasions (mean interval 136 days, minimum 7 days, maximum 6.7 yr). Olfac- tory function was assessed using a validated tech- nique (“Sniffin’ Sticks”). This test consists of three subtests, one for odor threshold (T), odor discrimina- tion (D), and odor identification (I), with possible re- sults ranging up to 16 points each. From the sum of the results from the three subtests a composite “TDI” score was obtained. Results: Forty-four patients indi- cated an improvement of olfactory function, whereas 39 patients reported no change. No subject reported deterioration of olfactory sensitivity. Subjects as- signed to group BETTER had higher TDI scores in the second olfactory tests than subjects assigned to the group UNCHANGED, both in absolute terms and as compared with the first olfactory test (effect “test oc- casion” by “self-assessed improvement,” P < .001). There was no significant difference between groups with respect to age and sex (P  .99 and .84, respec- tively). Logistic regression showed that more than 60% of the subjects reported an improvement of olfac- tory sensitivity when the TDI score increased by 5.5 points. Conclusion: We show that there is a statisti- cally significant relation between measured and per- ceived improvement of olfactory function in patients who first presented with the diagnosis of anosmia or hyposmia. The results indicate that improved olfac- tory function in patients with olfactory deficiency is perceived as such in everyday life and is quantita- tively related to an improvement in the composite TDI score of the “Sniffin’ Sticks” olfactory test bat- tery. This is the basis for the application of a specific therapy for olfactory loss because of a possible gain in quality of life for the patients. Key Words: Subjective olfaction, smell, olfactory testing. Laryngoscope, 116:1858 –1863, 2006 INTRODUCTION Monitoring of olfactory function in patients with smell disorders is essential to assess recovery from or progression of the dysfunction, respectively. It is indispensable to evalu- ate a therapeutic success. The direct way to monitor changes in olfactory func- tion is self-assessment by the patient. However, self- assessment of olfactory sensitivity reflects not only the sense of smell but is confounded by unspecific factors. 1 For example, self-assessment of olfactory sensitivity was shown to be correlated with ratings of nasal airway patency. 2 In addi- tion, self-assessment of olfactory sensitivity appears to be strongly influenced by the actual mood, motivation, and mo- tives of the patient. 3 The relation of self-assessed to mea- sured olfactory sensitivity may be further blurred by the limited attention that the sense of smell receives in daily life, even by patients with olfactory loss. To specifically quantify the functional level of olfac- tion, a number of tests have been designed and validated, for example, the University of Pennsylvania Smell Iden- tification Test, 4 the test of the Connecticut Clinical Che- mosensory Research Center, 5 or the “Sniffin’ Sticks” test. 6,7 These tests have become by now standardized and reliable tools for the assessment of different aspects of olfaction. They are successfully used for the specific as- sessment of olfactory function and quantify the patients’ performance for three dimensions of the sense of smell, namely the quantification of odor thresholds to defined test odors, assessment of odor discrimination, and odor identification (TDI). Thus, it is possible to specifically diagnose the func- tion of the olfactory system. However, once the diagnosis of olfactory dysfunction has been obtained, the subject/ patient will ask for the prognosis. Here, the self-assessed change of olfactory function is important for daily life. From the Department of Otorhinolaryngology (V.G., A.H., T.Z., T.H.), University of Dresden Medical School, Dresden, Germany, and Pharma- zentrum Frankfurt/ZAFES (J.L.), Institute of Clinical Pharmacology, Jo- hann Wolfgang Goethe-University, Frankfurt am Main, Germany. Editor’s Note: This Manuscript was accepted for publication June 15, 2006. Send correspondence to Dr. Thomas Hummel, Smell and Taste Clinic, Department of Otorhinolaryngology, University of Dresden Medical School (“Technische Universita ¨ t Dresden”), Fetscherstrasse 74, 01307 Dresden, Germany. E-mail: thummel@rcs.urz.tu-dresden.de DOI: 10.1097/01.mlg.0000234915.51189.cb Laryngoscope 116: October 2006 Gudziol et al.: Significance of Olfactory Test Results 1858