title: The effects of cognitive reserve and lifestyle on cognition and dementia in Parkinson's disease--a longitudinal cohort study.
abstract: OBJECTIVE
  Cognitive reserve theory seeks to explain the observed mismatch between the degree of brain pathology and clinical manifestations. Early-life education, midlife social and occupational activities and later-life cognitive and social interactions are associated with a more favourable cognitive trajectory in older people. Previous studies of Parkinson's disease (PD) have suggested a possible role for the effects of cognitive reserve, but further research into different proxies for cognitive reserve and longitudinal studies is required. This study examined the effects of cognitive lifestyle on cross-sectional and longitudinal measures of cognition and dementia severity in people with PD.
  
  
  METHODS
  Baseline assessments of cognition, and of clinical, social and demographic information, were completed by 525 participants with PD. Cognitive assessments were completed by 323 participants at 4-year follow-up. Cognition was assessed using the measures of global cognition dementia severity. Cross-sectional and longitudinal serial analyses of covariance for cognition and binomial regression for dementia were performed.
  
  
  RESULTS
  Higher educational level, socio-economic status and recent social engagement were associated with better cross-sectional global cognition. In those with normal cognition at baseline, higher educational level was associated with better global cognition after 4 years. Increasing age and low levels of a measure of recent social engagement were associated with an increased risk of dementia.
  
  
  CONCLUSIONS
  Higher cognitive reserve has a beneficial effect on performance on cognitive tests and a limited effect on cognitive decline and dementia risk in PD.
authors.affiliation: Department of Care of the Elderly, Betsi Cadwaladr University Health Board, Llandudno, UK.|North Wales Organisation for Randomised Trials in Health (NWORTH), Bangor University, Bangor, UK.
authors.forename: John V
authors.initials: JV
authors.lastname: Hindle
authors.affiliation: School of Health Sciences, City University London, London, UK.
authors.forename: Catherine S
authors.identifier: http://orcid.org/0000-0003-1571-0040
authors.initials: CS
authors.lastname: Hurt
authors.affiliation: Institute for Ageing and Health, Newcastle University, Newcastle upon Tyne, UK.
authors.forename: David J
authors.initials: DJ
authors.lastname: Burn
authors.affiliation: Department of Psychology, Institute of Psychiatry Psychology and Neuroscience, King's College London, London, UK.
authors.forename: Richard G
authors.initials: RG
authors.lastname: Brown
authors.affiliation: Department of Neurology, King's Health Partners, King's College Hospital, London, UK.|East Kent Hospitals NHS University Foundation Trust, Kent, UK.
authors.forename: Mike
authors.initials: M
authors.lastname: Samuel
authors.affiliation: EMI Academic Unit, St Catherine's Hospital, University of Liverpool, Wirral, UK.
authors.forename: Kenneth C
authors.initials: KC
authors.lastname: Wilson
authors.affiliation: School of Psychology, Exeter University, Devon, UK.|School of Psychology, Bangor University, Gwynedd, UK.
authors.forename: Linda
authors.initials: L
authors.lastname: Clare
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D003072:Cognition Disorders / Q000503:physiopathology*; D058245:Cognitive Reserve / Q000502:physiology*; D003430:Cross-Sectional Studies; D003704:Dementia / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008019:Life Style; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D010300:Parkinson Disease / Q000503:physiopathology*; D011446:Prospective Studies
keywords: Parkinson's disease; cognition; cognitive reserve; dementia; lifestyle