Impact of Hedonics and Magnitude Upon Validated Psychophysical Olfactory Tests and Olfactory-Specific Quality of Life.

Introduction: Patients often describe the olfactory loss as either the inability to detect unpleasant odors (eg, smoke or spoiled food) or noticeable impairment in enjoying pleasant odors (eg, food and fragrances). This complex relationship between the hedonics of various odors, their perceived magnitude in odor strength, and the impact on patient quality of life is not well understood.
Methods: Sixty-five subjects underwent testing with the Henkin olfaction test which assesses hedonics and magnitude for odors traditionally deemed unpleasant (pyridine/dead fish and thiophene/gasoline) and pleasant (amyl acetate/banana and nitrobenzene/almond). Subjects also completed Smell Identification Test-40 (SIT-40), Sniffin' Sticks (Sniffin' Sticks), and Snap & Sniffin' Sticks (Snap) Olfactory Tests, as well as the 17-item Questionnaire for Olfactory Disorders Negative Statements (QODNS) and olfactory symptom visual analog scale (VAS). Spearman's rank correlations were conducted between various olfactory domains, QODNS and VAS.
Results: Mean age was 52.1 years (range: 28-86), with 63.1% females. Magnitude estimation was greatest for pyridine. Most people rated thiophene (75.4%) and pyridine (92.3%) as "unpleasant." Although most people rated amyl acetate (47.7%) and nitrobenzene (56.9%) as "pleasant," many rated amyl acetate (52.3%) and nitrobenzene (43.1%) as "neutral" or "unpleasant" scents. Hedonics for unpleasant odors correlated with each other ( r _s  = 0.60), but not with hedonics for pleasant odors. Hedonics for unpleasant odors also correlated with magnitude estimation and other psychophysical tests. These findings were not seen for hedonics of pleasant odors.
Conclusions: The use of unpleasant odors in Henkin testing showed unique relationship patterns with patient-reported outcome measures and validated olfactory tests, which may provide utility in characterizing olfactory dysfunction. The incorporation of more unpleasant odors in current psychophysical olfactory testing may provide enhanced information regarding the patient impact of olfactory dysfunction.