Abstract

Objective
Drug-induced Parkinsonism (DIP) stands as a frequently encountered diagnostic possibility when considering Parkinson’s disease (PD). While olfactory dysfunction is a common clinical feature in PD, the comparison of olfactory function between two conditions remains insufficient. This study aimed to compare the olfactory function, including threshold, discrimination, and identification (TDI) profiles between PD and DIP.
Methods
Consecutive patients with drug-naïve PD (n=78) or DIP (n=31) confirmed through dopamine transporter image were enrolled in this study. The YSK olfactory function (YOF) test composed of TDI domains culturally familiar odorants to Koreans, was administered to all patients.
Results
In the study population, the patients with DIP were significantly older than the patients with PD. Over 70% of patients in each group had hyposmia or anosmia, and there was no significant difference in the occurrence of olfactory dysfunction between the two groups. In addition, there were no differences in the total YOF score and threshold score between the two groups. Meanwhile, the PD group had a significantly lower discrimination and identification score compared to the DIP group, after adjusting for age, sex, the existence of diabetes, disease duration, and cognitive function.
Conclusions
This study demonstrated that detailed olfactory profiles are different in PD and DIP, even though olfactory dysfunction can be observed in both conditions.

• Keywords: Parkinson disease, Drug-induced Parkinsonism, Anosmia, Olfactory dysfunction, Olfactory function test;