Olfactory anosognosia is a predictor of cognitive decline and dementia conversion in Parkinson’s disease

Han Soo Yoo, Seok Jong Chung, Yang Hyun Lee, Byoung Seok Ye, Young H. Sohn, Phil Hyu Lee

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)


Objective: Parkinson’s disease (PD) patients are often unaware of olfactory deficits despite having hyposmia from the early stages. We aimed to evaluate whether olfactory anosognosia is a predictor of cognitive decline in PD. Methods: In this retrospective cohort study, we recruited 77 PD patients who underwent both olfactory and neuropsychological tests and were followed-up for over 5 years. Based on the degree of olfactory dysfunction and awareness of its presence, patients were classified as normosmic patients (Normosmia group, n = 15), hyposmic patients without olfactory anosognosia (Hyposmia-OA−, n = 40), or hyposmic patients with olfactory anosognosia (Hyposmia-OA+, n = 22). We compared the rates of cognitive decline using linear mixed model and dementia conversion using a survival analysis among the groups. Results: A higher proportion of patients in the Hyposmia-OA+ group had mild cognitive impairment at baseline (77.3%) and dementia converter at follow-up (50.0%). The Hyposmia-OA+ group exhibited a faster decline in frontal executive and global cognitive function than did the Normosmia and Hyposmia-OA− groups. A Kaplan–Meier analysis demonstrated that the conversion rate to dementia was significantly higher in the Hyposmia-OA+ group than in the Normosmia (P = 0.007) and Hyposmia-OA− (P = 0.038) groups. A Cox regression analysis showed that olfactory anosognosia remained a significant predictor of time to develop dementia in the Hyposmia-OA+ group compared to the Normosmia group (adjusted hazard ratio 3.30; 95% confidence interval 1.10–8.21). Conclusion: This study suggests that olfactory anosognosia is a predictor of cognitive decline and dementia conversion in PD.

Original languageEnglish
Pages (from-to)1601-1610
Number of pages10
JournalJournal of Neurology
Issue number7
Publication statusPublished - 2019 Jul 1

Bibliographical note

Funding Information:
Acknowledgements This study was supported by a grant of the Korea Health Technology R&D Project through the Korea Health Industry Development Institute (KHIDI), funded by the Ministry of Health & Welfare, Republic of Korea (grant number: HI16C1118).

Publisher Copyright:
© 2019, Springer-Verlag GmbH Germany, part of Springer Nature.

All Science Journal Classification (ASJC) codes

  • Neurology
  • Clinical Neurology


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