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Medical decision-making capacity in cognitively impaired Parkinson's disease patients without dementia

Authors

  • Roy C. Martin PhD,

    1. Department of Neurology, University of Alabama at Birmingham, Birmingham, Alabama, USA
    2. Alzheimer's Disease Research Center, University of Alabama at Birmingham, Birmingham, Alabama, USA
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  • Ozioma C. Okonkwo MA,

    1. Department of Psychology, University of Alabama at Birmingham, Birmingham, Alabama, USA
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  • Joni Hill,

    1. Department of Psychology, University of Alabama at Birmingham, Birmingham, Alabama, USA
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  • H. Randall Griffith PhD,

    1. Department of Neurology, University of Alabama at Birmingham, Birmingham, Alabama, USA
    2. Alzheimer's Disease Research Center, University of Alabama at Birmingham, Birmingham, Alabama, USA
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  • Kristen Triebel PsyD,

    1. Department of Neurology, University of Alabama at Birmingham, Birmingham, Alabama, USA
    2. Alzheimer's Disease Research Center, University of Alabama at Birmingham, Birmingham, Alabama, USA
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  • Alfred Bartolucci PhD,

    1. Alzheimer's Disease Research Center, University of Alabama at Birmingham, Birmingham, Alabama, USA
    2. Department of Biostatistics, University of Alabama at Birmingham, Birmingham, Alabama, USA
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  • Anthony P. Nicholas MD, PhD,

    1. Department of Neurology, University of Alabama at Birmingham, Birmingham, Alabama, USA
    2. Alzheimer's Disease Research Center, University of Alabama at Birmingham, Birmingham, Alabama, USA
    3. Veterans Administration Medical Center, Birmingham, Alabama, USA
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  • Ray L. Watts MD,

    1. Department of Neurology, University of Alabama at Birmingham, Birmingham, Alabama, USA
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  • Natividad Stover MD,

    1. Department of Neurology, University of Alabama at Birmingham, Birmingham, Alabama, USA
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  • Lindy E. Harrell PhD, MD,

    1. Alzheimer's Disease Research Center, University of Alabama at Birmingham, Birmingham, Alabama, USA
    2. Department of Biostatistics, University of Alabama at Birmingham, Birmingham, Alabama, USA
    3. Veterans Administration Medical Center, Birmingham, Alabama, USA
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    • David Clark MD,

      1. Alzheimer's Disease Research Center, University of Alabama at Birmingham, Birmingham, Alabama, USA
      2. Department of Biostatistics, University of Alabama at Birmingham, Birmingham, Alabama, USA
      3. Veterans Administration Medical Center, Birmingham, Alabama, USA
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    • Daniel C. Marson JD, PhD

      Corresponding author
      1. Department of Neurology, University of Alabama at Birmingham, Birmingham, Alabama, USA
      2. Alzheimer's Disease Research Center, University of Alabama at Birmingham, Birmingham, Alabama, USA
      • Department of Neurology, Sparks Center 650, 1720 7th Avenue South, University of Alabama at Birmingham, Birmingham, AL 35294-0017
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      • Dr. Marson and Dr. Harrell receive royalty income through UABRF.


    • Potential conflict of interest: The decisional capacity measure used in the study is owned by the UAB Research Foundation (UABRF).

    Abstract

    Little is currently known about the higher order functional skills of patients with Parkinson disease and cognitive impairment. Medical decision-making capacity (MDC) was assessed in patients with Parkinson's disease (PD) with cognitive impairment and dementia. Participants were 16 patients with PD and cognitive impairment without dementia (PD-CIND), 16 patients with PD dementia (PDD), and 22 healthy older adults. All participants were administered the Capacity to Consent to Treatment Instrument (CCTI), a standardized capacity instrument assessing MDC under five different consent standards. Parametric and nonparametric statistical analyses were utilized to examine capacity performance on the consent standards. In addition, capacity outcomes (capable, marginally capable, or incapable outcomes) on the standards were identified for the two patient groups. Relative to controls, PD-CIND patients demonstrated significant impairment on the understanding treatment consent standard, clinically the most stringent CCTI standard. Relative to controls and PD-CIND patients, PDD patients were impaired on the three clinical standards of understanding, reasoning, and appreciation. The findings suggest that impairment in decisional capacity is already present in cognitively impaired patients with PD without dementia and increases as these patients develop dementia. Clinicians and researchers should carefully assess decisional capacity in all patients with PD with cognitive impairment. © 2008 Movement Disorder Society

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