Severity of mild cognitive impairment in early Parkinson's disease contributes to poorer quality of life

Rachael A Lawson, Alison J Yarnall, Gordon W Duncan, Tien K Khoo, David P Breen, Roger A Barker, Daniel Collerton, John-Paul Taylor, David J Burn

Research output: Contribution to journalArticlepeer-review

Abstract / Description of output

BACKGROUND: Poor quality of life (QoL) is a feature of people with Parkinson's disease (PD) who develop dementia. The relationship between mild cognitive impairment in PD (PD-MCI) and QoL is less clear. To address this, we studied the impact of varying severities of cognitive impairment on QoL in a cohort of non-demented patients with early PD.

METHOD: Patients with newly diagnosed PD (n = 219) and age and sex matched healthy controls (n = 99) completed a schedule of neuropsychological tests, in addition to scales assessing QoL (PDQ-39), depression, sleep, neuropsychiatric symptoms and a clinical examination. The Movement Disorder Society criteria were used to define and classify PD-MCI.

RESULTS: Participants with PD-MCI were significantly older than those with normal cognition, had more severe motor symptoms, scored higher for depression and had poorer quality of life. Logistic regression showed that mild cognitive impairment, independent of other factors, was an indicator of poorer QoL. Using cognitive performance 2.0 standard deviations (SD) below normative data as a cut-off to define PD-MCI, there was a significant difference in QoL scores between patients with PD-MCI and those classified as having normal cognition. Subjects with less severe mild cognitive impairment did not exhibit significant differences in QoL.

CONCLUSIONS: PD-MCI is a significant, independent factor contributing to poorer QoL in patients with newly diagnosed PD. Those classified with greatest impairment (2.0 SD below normal values) have lower QoL. This has implications for clinical practice and future interventions targeting cognitive impairments.

Original languageEnglish
Pages (from-to)1071-5
Number of pages5
JournalParkinsonism & Related Disorders
Issue number10
Publication statusPublished - Oct 2014

Keywords / Materials (for Non-textual outputs)

  • Aged
  • Attention
  • Executive Function
  • Female
  • Humans
  • Male
  • Memory
  • Middle Aged
  • Mild Cognitive Impairment
  • Neuropsychological Tests
  • Parkinson Disease
  • Predictive Value of Tests
  • Quality of Life
  • Space Perception
  • Statistics, Nonparametric


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