What is the correlation between ratings and measures of olfactory function in patients with olfactory loss?

Background: Major complaints of many patients with olfactory dysfunction relate to the impairment of quality of life. Nevertheless, it is unclear to what extent there is a correlation between ratings of olfactory abilities/impairment and olfactory function.

Methods: Patients with olfactory dysfunction (n = 152) were examined psychometrically using the "Sniffin' Sticks" test battery. Ratings of olfactory function and ratings of impairment were recorded using visual analog scales.

Results: Following standardized olfactory testing, 78 of the 152 patients were categorized as functionally anosmic, 64 as hyposmic, and 10 as normosmic. Groups differed significantly with regard to ratings of olfactory function. Functionally anosmic patients rated impairment to be significantly higher compared with hyposmic and normosmic patients. Ratings of olfactory function correlated significantly with measured olfactory function (r = +0.57) and ratings of impairment (r = -0.30).

Conclusion: There was a moderate correlation between ratings and measures of olfactory function. On average, functionally anosmic patients recognized their olfactory loss, although, on an individual basis, there were striking differences between measures and ratings of olfactory function.