Apomorphine does not influence olfactory thresholds in Parkinson's disease

In order to verify the presumed dopaminergic basis of olfactory dysfunction in Parkinson's disease (PD), we studied olfactory functions in 12 PD patients (mean age 60.1 yrs, mean duration of PD 9.0 yrs, mean Hoehn and Yahr score 2.8) before and after apomorphine (APO) administration. Amylacetate (banana smell) in 12 sequential dilutions (in 50% steps) was used for the examination of olfactory thresholds. The testing showed no significant differences in any olfactory parameters before and after APO. Furthermore, when analysing the subgroup of 7 hyposmic PD patients, we also found no significant differences before and after APO. We therefore believe that olfactory dysfunction in PD is not dependent on dopamine deficiency.