Clinical Research Fellow Medical University of South Carolina
Introduction: Multiple tests have been developed and validated to assess olfaction. Studies examining olfaction often use only a single olfaction test or quality-of-life measure, and investigated domains of olfaction may vary. Because there is a paucity of data comparing these psychophysical olfactory tests and quality-of-life measures, results are difficult to compare between studies.
Methods: Subjects (N=41) were prospectively enrolled for olfaction testing with the Smell Identification Test-40 (SIT40), Sniffin’ Sticks (Sniff), and Snap & Sniff (Snap) Olfactory Tests. Tested domains of olfaction included threshold, discrimination, and identification. Each subject completed the seventeen-item Questionnaire on Olfactory Disorders (QOD) and olfactory symptom visual analog scale (VAS). Spearman correlations were conducted for olfaction tests vs QOD and VAS.
Results: There were 19 normosmic, 13 hyposmic, and 9 anosmic subjects. In general, all 3 psychophysical tests showed moderate to strong correlations. The strongest correlations were found between the identification components of the various tests (r>0.836, p<0.0001). Threshold and discrimination components also had moderate to strong correlations (r>0.696, p<0.0001). Total QOD and olfactory-specific VAS symptom scores correlated moderately with all test measures (r=-0.407 to -0.598, p<0.001 to 0.008) with significant variability for individual questions.
Conclusions: Olfactory psychophysical tests correlate strongly between 3 common validated measures. Olfactory dysfunction is moderately associated with greater impact on quality of life and olfactory symptom severity with variability among specific questions.