The Discriminative Power of Different Olfactory Domains in Parkinson's Disease

Yuwen Zhao; Yan He; Runcheng He; Yangjie Zhou; Hongxu Pan; Xiaoting Zhou; Liping Zhu; Xun Zhou; Zhenhua Liu; Qian Xu; Qiying Sun; Jieqiong Tan; Xinxiang Yan; Beisha Tang; Jifeng Guo

doi:10.3389/fneur.2020.00420

The Discriminative Power of Different Olfactory Domains in Parkinson's Disease

Front Neurol. 2020 Jun 2:11:420. doi: 10.3389/fneur.2020.00420. eCollection 2020.

Authors

Yuwen Zhao¹, Yan He¹, Runcheng He¹, Yangjie Zhou¹, Hongxu Pan¹, Xiaoting Zhou¹, Liping Zhu¹, Xun Zhou¹, Zhenhua Liu¹, Qian Xu¹, Qiying Sun^{1

2}, Jieqiong Tan³, Xinxiang Yan¹, Beisha Tang^{1

2

3

4

5}, Jifeng Guo^{1

3

4

5}

Affiliations

¹ Department of Neurology, Xiangya Hospital, Central South University, Changsha, China.
² Department of Geriatrics, Xiangya Hospital, Central South University, Changsha, China.
³ Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, China.
⁴ Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, China.
⁵ National Clinical Research Center for Geriatric Disorders, Changsha, China.

Abstract

Background and Purpose: Olfactory dysfunction is one of the most common non-motor symptoms in Parkinson's disease (PD) preceding the motor symptoms for years. This study aimed to evaluate different olfactory domains in PD patients in comparison with healthy controls and to explore the relationships among olfactory deficit and other clinical manifestations in patients with PD. Methods: Sniffin' Sticks test, which detects olfactory threshold, discrimination, and identification (TDI), were conducted in 500 PD patients and 115 controls. Furthermore, demographic and clinical data including motor and other non-motor symptoms were collected. Results: In the single olfactory model, the identification test showed the area under the receiver operating characteristic (ROC) curve (AUC = 0.818), followed by threshold test (AUC = 0.731) and discrimination test (AUC = 0.723). Specifically, the identification test has a similar discriminative power as the TDI score (0.818 and 0.828, respectively, p = 0.481). In the integrated olfactory model involved with other non-motor manifestations, identification test scores performed as good as the TDI score in differentiating PD patients from controls (0.916 and 0.918, respectively, p = 0.797). In PD patients, age and cognition together explained 7.5% of the variance of the threshold score, while age, cognition, and gender accounted for the 15.2% explained variance of the discrimination score, while cognition, age, the ability of daily living, and gender together interpreted 11.1% of the variance of the identification score. Conclusion: Our results indicated that the identification domain was the most practical olfactory factor in differentiating PD patients, and the combination of several different manifestations was better than a single symptom. Furthermore, the olfactory identification score may be associated with the ability of daily living.

Keywords: Chinese population; Parkinson's disease; Sniffin' sticks; olfactory domains; olfactory dysfunction.