Cognitive decline in early Parkinson's disease

Authors

  • Nagaendran Kandiah MBBS, MRCP,

    Corresponding author
    1. Department of Neurology, National Neuroscience Institute, Singapore
    • Level 3, Clinical Staff Office, National Neuroscience Institute, 11 Jalan Tan Tock Seng, Singapore 308433, Singapore
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  • Kaavya Narasimhalu BA,

    1. Center for Molecular Epidemiology, Department of Community, Occupational and Family Medicine, National University of Singapore, Singapore
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  • Puay-Ngoh Lau BHSc,

    1. Department of Neurology, National Neuroscience Institute, Singapore
    2. Parkinson's Disease and Movement Disorders Centre, Department of Neurology, National Neuroscience Institute, Singapore
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  • Soo-Hoon Seah,

    1. Department of Neurology, National Neuroscience Institute, Singapore
    2. Parkinson's Disease and Movement Disorders Centre, Department of Neurology, National Neuroscience Institute, Singapore
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  • Wing Lok Au MBBS, MRCP, FRCP,

    1. Department of Neurology, National Neuroscience Institute, Singapore
    2. Parkinson's Disease and Movement Disorders Centre, Department of Neurology, National Neuroscience Institute, Singapore
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  • Louis C.S. Tan MBBS, MRCP, FRCP

    1. Department of Neurology, National Neuroscience Institute, Singapore
    2. Parkinson's Disease and Movement Disorders Centre, Department of Neurology, National Neuroscience Institute, Singapore
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  • Potential conflict of interest: None.

Abstract

Data on the prevalence and severity of cognitive impairment among patients with newly diagnosed idiopathic Parkinson's disease (PD) is limited. Using a prospectively collected clinical database, we studied the longitudinal trend of mini-mental state examination (MMSE) change and baseline factors predictive for MMSE decline. One hundred six patients with mean age of 61.2 years and mean baseline MMSE of 27.8 ± 2.3 were studied. MMSE increased by 0.4 points/year among patients without cognitive decline (n = 73) and decreased by 2.39 points/year among patients with cognitive decline (n = 33). Univariate analysis demonstrated education, age of diagnosis, depression, and diabetes mellitus to be associated with cognitive decline. Motor scores and hallucination were not associated with cognitive decline. Multivariate analysis demonstrated higher level of education to be protective (HR = 0.91, 95% CI 0.82–0.99, P = 0.047) and depression having borderline significance in predicting cognitive decline (HR = 2.00, 95% CI 0.97–4.15, P = 0.061). We found that 31% of newly diagnosed idiopathic PD patients have measurable cognitive decline at an early stage of disease. Higher education is protective while depression may be predictive of cognitive decline. © 2009 Movement Disorder Society

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