title: Cognitive decline in Parkinson disease.
abstract: Dementia is a frequent problem encountered in advanced stages of Parkinson disease (PD). In recent years, research has focused on the pre-dementia stages of cognitive impairment in PD, including mild cognitive impairment (MCI). Several longitudinal studies have shown that MCI is a harbinger of dementia in PD, although the course is variable, and stabilization of cognition - or even reversal to normal cognition - is not uncommon. In addition to limbic and cortical spread of Lewy pathology, several other mechanisms are likely to contribute to cognitive decline in PD, and a variety of biomarker studies, some using novel structural and functional imaging techniques, have documented in vivo brain changes associated with cognitive impairment. The evidence consistently suggests that low cerebrospinal fluid levels of amyloid-β42, a marker of comorbid Alzheimer disease (AD), predict future cognitive decline and dementia in PD. Emerging genetic evidence indicates that in addition to the APOE*ε4 allele (an established risk factor for AD), GBA mutations and SCNA mutations and triplications are associated with cognitive decline in PD, whereas the findings are mixed for MAPT polymorphisms. Cognitive enhancing medications have some effect in PD dementia, but no convincing evidence that progression from MCI to dementia can be delayed or prevented is available, although cognitive training has shown promising results.
authors.affiliation: KCL-PARCOG group, Institute of Psychiatry, Psychology &Neuroscience, King's College London, De Crespigny Park, London SE5 8AF, UK.|Department of Old Age Psychiatry, Institute of Psychiatry, Psychology &Neuroscience, King's College London, De Crespigny Park, London SE5 8AF, UK.
authors.forename: Dag
authors.initials: D
authors.lastname: Aarsland
authors.affiliation: KCL-PARCOG group, Institute of Psychiatry, Psychology &Neuroscience, King's College London, De Crespigny Park, London SE5 8AF, UK.|University of Exeter Medical School, University of Exeter, Exeter EX1 2LU, UK.
authors.forename: Byron
authors.initials: B
authors.lastname: Creese
authors.affiliation: KCL-PARCOG group, Institute of Psychiatry, Psychology &Neuroscience, King's College London, De Crespigny Park, London SE5 8AF, UK.|Neurodegeneration Imaging Group, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology &Neuroscience, King's College London, 125 Coldharbour Lane, London SE5 9NU, UK.
authors.forename: Marios
authors.initials: M
authors.lastname: Politis
authors.affiliation: KCL-PARCOG group, Institute of Psychiatry, Psychology &Neuroscience, King's College London, De Crespigny Park, London SE5 8AF, UK.|Department of Basic and Clinical Neuroscience, Maurice Wohl Clinical Neuroscience Institute, National Parkinson Foundation Centre of Excellence, King's College London/Kings College Hospital, 5 Cutcombe Road, London SE5 9RT, UK.
authors.forename: K Ray
authors.initials: KR
authors.lastname: Chaudhuri
authors.affiliation: KCL-PARCOG group, Institute of Psychiatry, Psychology &Neuroscience, King's College London, De Crespigny Park, London SE5 8AF, UK.|Department of Old Age Psychiatry, Institute of Psychiatry, Psychology &Neuroscience, King's College London, De Crespigny Park, London SE5 8AF, UK.
authors.forename: Dominic H
authors.initials: DH
authors.lastname: Ffytche
authors.affiliation: KCL-PARCOG group, Institute of Psychiatry, Psychology &Neuroscience, King's College London, De Crespigny Park, London SE5 8AF, UK.|Departments of Psychiatry and Neurology, Perelman School of Medicine at the University of Pennsylvania 3615 Chestnut Street, #330, Philadelphia, Pennsylvania 19104, USA.|Parkinson's Disease and Mental Illness Research, Education and Clinical Centres (PADRECC and MIRECC), Philadelphia Veterans Affairs Medical Centre 3900 Woodland Avenue, Philadelphia, Pennsylvania 19104, USA.
authors.forename: Daniel
authors.initials: D
authors.lastname: Weintraub
authors.affiliation: KCL-PARCOG group, Institute of Psychiatry, Psychology &Neuroscience, King's College London, De Crespigny Park, London SE5 8AF, UK.|University of Exeter Medical School, University of Exeter, Exeter EX1 2LU, UK.
authors.forename: Clive
authors.initials: C
authors.lastname: Ballard
mesh_terms: D060825:Cognitive Dysfunction / Q000209:etiology / Q000378:metabolism / Q000473:pathology; D003704:Dementia / Q000209:etiology / Q000378:metabolism / Q000473:pathology; D006801:Humans; D010300:Parkinson Disease / Q000150:complications / Q000378:metabolism / Q000473:pathology