Assessment of postviral qualitative olfactory dysfunction using the short SSParoT in patients with and without parosmia

Purpose To examine if the short formed Sniffin Sticks Parosmia Test (SSParoT), a test for parosmia can distinguish cases with parosmia from cases without parosmia. Methods In this study, 63 patients with postviral olfactory dysfunction were investigated including both COVID and non-COVID cases. The age, symptom duration, degree of parosmia/phantosmia was collected. For olfactory function, the Sniffin Sticks olfactory score was obtained including scores for odor threshold, discrimination and identification. For assessment of parosmic changes, the short SSParoT was adopted and both hedonic range (HedRang) and direction (HedDir) was calculated. Results The mean HedRang of patients with parosmia (2.35, standard deviation, SD = 1.40) and without parosmia (2.78, SD = 1.09) was smaller than that in controls (4.5, SD = 2.15). However, the mean HedDir of both parosmia (- 0.32, SD = 0.98) and non-parosmia patients (0.04, SD = 1.07) was similar to controls (- 0.1, SD = 1.55). When considering that the 10(th) percentile of the distribution of SSParoT score should distinguish between patients with and without parosmia, the sensitivity of the HedRang was 29% and specificity was 67%. For HedDir, the sensitivity was 6% and specificity was 100%. Only the odor identification score (r = 0.34, p = 0.01) discriminated parosmia and non-parosmia while other measures including HedRang and HedDir did not. Conclusion The present study showed that the short SSParoT score could not distinguish patients with parosmia from patients without parosmia. Although the SSParoT represents an innovative approach to assess parosmia, and could be useful in the tracking of parosmic changes, the development of measures to diagnose parosmia in an objective way remains a challenge.