Odor selectivity of hyposmia and cognitive impairment in patients with Parkinson’s disease
Authors Mao CJ, Wang F, Chen JP, Yang YP, Chen J, Huang JY, Liu CF
Received 28 July 2017
Accepted for publication 22 August 2017
Published 9 October 2017 Volume 2017:12 Pages 1637—1644
Checked for plagiarism Yes
Review by Single-blind
Peer reviewers approved by Dr Colin Mak
Peer reviewer comments 2
Editor who approved publication: Dr Wu
Cheng-Jie Mao,1 Fen Wang,2 Ju-Ping Chen,3 Ya-Ping Yang,1 Jing Chen,1 Juan-Ying Huang,1 Chun-Feng Liu1,2
1Department of Neurology and Suzhou Clinical Research Center of Neurological Disease, the Second Affiliated Hospital of Soochow University, 2Institute of Neuroscience, Soochow University, Suzhou, 3Department of Neurology, Hospital of Changshu Traditional Chinese Medicine, Changshu, People’s Republic of China
Objective: Hyposmia is one of the earliest non-motor features of Parkinson’s disease (PD) and can precede the onset of motor symptoms by years. Most of the current olfactory detection tests are targeted at Western populations. The exact relationship between hyposmia and cognitive impairment is unknown. The purpose of the study was to find bromines that can effectively identify olfactory dysfunction and investigate the relationship between hyposmia and cognitive function in early, non-demented, drug-naïve patients with PD in the People’s Republic of China.
Methods: Sixty-three early, non-demented, drug-naïve patients with PD and 55 healthy controls were enrolled in the study. The T&T olfactometer and a Chinese version of Montreal Cognitive Assessment (MoCA) were applied to assess subjects’ olfactory and cognitive functions. Patients with PD also completed the Modified Unified Parkinson’s disease-rating scale (UPDRS) and Hoehn and Yahr (H&Y) scale.
Results: Patients with PD had lower scores of visuospatial and executive function (p=0.000), attention (p=0.03), and delayed recall (p=0.001) than controls. β-phenylethyl alcohol (floral smell, smell of rose petals) and isovaleric acid (smell of sweat, stuffy socks) were more sensitive for identifying hyposmia in patients with PD than three other odors. Multivariate logistic regression analysis showed that impaired visuospatial and executive function was associated with hyposmia (p=0.013), but was independent of other PD-associated variables.
Conclusion: Hyposmia was common in early, non-demented, drug-naïve PD patients. β-Phenylethyl alcohol and isovaleric acid were more superior for identifying hyposmia in early non-demented Chinese patients with PD. Hyposmia was associated with impaired visuospatial and executive function in patients with PD. Further prospective studies that apply a series of neuropsychological tests and functional magnetic resonance imaging methods in large samples in multicenter studies are needed to confirm our findings and to investigate the relationship between hyposmia and cognitive function with disease progression in patients with PD.
Keywords: Parkinson’s disease, hyposmia, cognitive dysfunction
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