title: Biomarkers for dementia and mild cognitive impairment in Parkinson's disease.
abstract: Cognitive decline is one of the most frequent and disabling nonmotor features of Parkinson's disease. Around 30% of patients with Parkinson's disease experience mild cognitive impairment, a well-established risk factor for the development of dementia. However, mild cognitive impairment in patients with Parkinson's disease is a heterogeneous entity that involves different types and extents of cognitive deficits. Because it is not currently known which type of mild cognitive impairment confers a higher risk of progression to dementia, it would be useful to define biomarkers that could identify these patients to better study disease progression and possible interventions. In this sense, the identification among patients with Parkinson's disease and mild cognitive impairment of biomarkers associated with dementia would allow the early detection of this process. This review summarizes studies from the past 25 years that have assessed the potential biomarkers of dementia and mild cognitive impairment in Parkinson's disease patients. Despite the potential importance, no biomarker has as yet been validated. However, features such as low levels of epidermal and insulin-like growth factors or uric acid in plasma/serum and of Aß in CSF, reduction of cerebral cholinergic innervation and metabolism measured by PET mainly in posterior areas, and hippocampal atrophy in MRI might be indicative of distinct deficits with a distinct risk of dementia in subgroups of patients. Longitudinal studies combining the existing techniques and new approaches are needed to identify patients at higher risk of dementia. © 2016 International Parkinson and Movement Disorder Society.
authors.affiliation: Biodonostia Health Research Institute, San Sebastián, Spain.|Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.
authors.forename: Manuel
authors.initials: M
authors.lastname: Delgado-Alvarado
authors.affiliation: Biodonostia Health Research Institute, San Sebastián, Spain.|Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.
authors.forename: Belén
authors.initials: B
authors.lastname: Gago
authors.affiliation: Biodonostia Health Research Institute, San Sebastián, Spain.|Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.
authors.forename: Irene
authors.initials: I
authors.lastname: Navalpotro-Gomez
authors.affiliation: Biodonostia Health Research Institute, San Sebastián, Spain.|Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.
authors.forename: Haritz
authors.initials: H
authors.lastname: Jiménez-Urbieta
authors.affiliation: Biodonostia Health Research Institute, San Sebastián, Spain.|Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.|Neurology Department, University Hospital Donostia, San Sebastián, Spain.|Ikerbasque (Basque Foundation for Science), Bilbao, Spain.|Basque Center on Cognition, Brain and Language (BCBL), San Sebastián, Spain.|Physiology Department, Medical School University of Navarra, Pamplona, Spain.
authors.forename: María C
authors.initials: MC
authors.lastname: Rodriguez-Oroz
mesh_terms: D015415:Biomarkers; D060825:Cognitive Dysfunction / Q000097:blood / Q000134:cerebrospinal fluid / Q000000981:diagnostic imaging / Q000209:etiology; D003704:Dementia / Q000097:blood / Q000134:cerebrospinal fluid / Q000000981:diagnostic imaging / Q000209:etiology; D006801:Humans; D010300:Parkinson Disease / Q000097:blood / Q000134:cerebrospinal fluid / Q000150:complications / Q000000981:diagnostic imaging
chemical_list: D015415:Biomarkers
keywords: Parkinson's disease; biomarkers; dementia; mild cognitive impairment