title: Dementia in Parkinson's disease.
abstract: OBJECTIVE
  Cognitive impairment and dementia are among the most common nonmotor changes in Parkinson's disease. The purpose of this review is to present recent findings of clinical and neurobiological aspects of dementia in Parkinson's disease.
  
  
  RESULTS
  New consensus criteria for a clinical diagnosis of dementia in Parkinson's disease have been proposed. A very high cumulative prevalence of dementia in Parkinson's disease has been shown in two independent long-term cohorts. Mild cognitive impairment occurs even in early Parkinson's disease and is associated with a shorter time to dementia. Emerging evidence from pathology, as well as in-vivo studies using novel techniques within genetics, imaging, and cerebrospinal fluid research, indicates that alpha-synuclein aggregation and disturbances of other candidate proteins are associated with dementia in Parkinson's disease. Clinical, pathological, and electrophysiological studies support the hypothesis of different subtypes of dementia in Parkinson's disease, potentially related to different underlying brain changes.
  
  
  CONCLUSIONS
  Increased understanding of underlying mechanisms of cognitive decline and dementia in Parkinson's disease has been achieved. This will hopefully lead to novel treatment with the potential of preventing or delaying the onset of dementia by influencing these mechanisms.
authors.affiliation: Norwegian Centre for Movement Disorders, Stavenger University Hospital, Stavenger.
authors.forename: Dag
authors.initials: D
authors.lastname: Aarsland
authors.forename: Mona K
authors.initials: MK
authors.lastname: Beyer
authors.forename: Martin W
authors.initials: MW
authors.lastname: Kurz
mesh_terms: D003704:Dementia / Q000134:cerebrospinal fluid / Q000453:epidemiology / Q000209:etiology* / Q000235:genetics; D003952:Diagnostic Imaging; D004594:Electrophysiology; D006801:Humans; D010300:Parkinson Disease / Q000150:complications*