Objective Drug-induced parkinsonism (DIP) is 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 the two conditions remains insufficient. This study aimed to compare 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 imaging 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, patients with DIP were significantly older than 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 than the DIP group after adjusting for age, sex, the existence of diabetes, disease duration, and cognitive function.
Conclusion This study demonstrated that detailed olfactory profiles are different in PD and DIP, even though olfactory dysfunction can be observed in both conditions.
Citations
Citations to this article as recorded by
Olfactory dysfunction as potential biomarker in neurodegenerative diseases: a narrative review Nicolas De Cleene, Katarína Schwarzová, Samuel Labrecque, Clancy Cerejo, Atbin Djamshidian, Klaus Seppi, Beatrice Heim Frontiers in Neuroscience.2025;[Epub] CrossRef
Objective
Patients with drug-induced parkinsonism (DIP) may have nigrostriatal dopaminergic degeneration. We studied the clinical features that may indicate nigrostriatal dopaminergic degeneration in patients with DIP.
Methods
Forty-one DIP patients were classified into normal and abnormal [18F] FP-CIT scan groups. Differences in 32 clinical features and drug withdrawal effects were studied.
Results
Twenty-eight patients had normal (Group I) and 13 patients had abnormal (Group II) scans. Eight patients of Group I, but none of Group II, had taken calcium channel blockers (p = 0.040). Three patients of Group I and six of Group II had hyposmia (p = 0.018). After drug withdrawal, Group I showed greater improvement in Unified Parkinson’s Disease Rating Scale total motor scores and subscores for bradykinesia and tremors than Group II. Only hyposmia was an independent factor associated with abnormal scans, but it had suboptimal sensitivity.
Conclusion
None of the clinical features were practical indicators of nigrostriatal dopaminergic degeneration in patients with DIP.
Citations
Citations to this article as recorded by
Comparative Olfactory Profiles in Parkinson’s Disease and Drug-Induced Parkinsonism In Hee Kwak, Young Eun Kim, Suk Yun Kang, Joong Seob Lee, Jeongjae Lee, Min Seung Kim, Dong A Yea, Hyeo-il Ma Journal of Movement Disorders.2024; 17(1): 64. CrossRef
Retinal Thickness and Its Interocular Asymmetry Between Parkinson’s Disease and Drug-Induced Parkinsonism Wool Suh, Sung Uk Baek, Jungsu S. Oh, Seung Yeon Seo, Jae Seung Kim, You Mie Han, Min Seung Kim, Suk Yun Kang Journal of Korean Medical Science.2023;[Epub] CrossRef
Gait abnormalities and non-motor symptoms predict abnormal dopaminergic imaging in presumed drug-induced Parkinsonism Whitley W. Aamodt, Jacob G. Dubroff, Gang Cheng, Betty Taylor, Stephanie Wood, John E. Duda, James F. Morley npj Parkinson's Disease.2022;[Epub] CrossRef
Acute dopamine receptor blockade in substantia nigra pars reticulata: a possible model for drug-induced Parkinsonism Verónica Alejandra Cáceres-Chávez, Ricardo Hernández-Martínez, Jesús Pérez-Ortega, Marco Arieli Herrera-Valdez, Jose J. Aceves, Elvira Galarraga, José Bargas Journal of Neurophysiology.2018; 120(6): 2922. CrossRef
Neuroimaging in Parkinson's disease: focus on substantia nigra and nigro-striatal projection Daniela Frosini, Mirco Cosottini, Duccio Volterrani, Roberto Ceravolo Current Opinion in Neurology.2017; 30(4): 416. CrossRef