title: Cognitive and neuroanatomical correlates of neuropsychiatric symptoms in Parkinson's disease: A systematic review.
abstract: BACKGROUND
  Neuropsychiatric symptoms are one of the most common non-motor symptoms in Parkinson's disease (PD). These symptoms have a negative impact on daily living activities and cognitive abilities. This review will be centred on published articles which focused on clarifying the cognitive and neuroanatomical features associated with the appearance of specific neuropsychiatric symptoms in this disease.
  
  
  METHODS
  All articles indexed in the Web of Science and PubMed databases were reviewed for potential inclusion in October 2014. In the first stage of the review, we identified 41 articles that investigated neuropsychiatric symptoms and cognitive impairments in PD. In the second stage, there were 26 published articles on the neural bases of neuropsychiatric symptoms in PD.
  
  
  RESULTS
  The main findings revealed that executive dysfunctions were common in patients with depression, apathy, visual hallucinations (VH), impulse control disorders (ICDs) and anxiety, whereas, memory deficits were associated mainly with depression and VH. Imaging studies have shown that frontal lobe atrophy was frequently observed in patients with depression, apathy, VH and ICDs.
  
  
  CONCLUSIONS
  This review gives a snapshot of those cognitive and neural correlates of neuropsychiatric symptoms in PD. Methodological shortcoming in the available studies were identified, however, of which the most critical appeared neglecting the presence of multiple neuropsychiatric symptoms in some of the patients included in studies of specific individual symptoms. Additionally, in most studies only patients in the moderate to severe stages were included which limits possible inferences to the early stage of the disease.
authors.affiliation: Department of Neuroscience, Faculty of Medicine, University of Sheffield, UK; National Neuroscience Institute, King Fahad Medical City, Riyadh, Saudi Arabia.
authors.forename: Hamad
authors.initials: H
authors.lastname: Alzahrani
authors.affiliation: Department of Neuroscience, Faculty of Medicine, University of Sheffield, UK; IRCCS Fondazione Ospedale San Camillo, Venice, Italy. Electronic address: a.venneri@sheffield.ac.uk.
authors.forename: Annalena
authors.initials: A
authors.lastname: Venneri
mesh_terms: D057565:Apathy; D003072:Cognition Disorders / Q000209:etiology*; D016206:Databases, Bibliographic / Q000706:statistics & numerical data; D056344:Executive Function / Q000502:physiology; D005625:Frontal Lobe / Q000378:metabolism*; D006212:Hallucinations / Q000209:etiology; D006801:Humans; D008570:Memory, Short-Term / Q000502:physiology; D019964:Mood Disorders / Q000209:etiology*; D010300:Parkinson Disease / Q000150:complications* / Q000473:pathology*
keywords: Anxiety; Apathy; Cognition; Depression; Impulse control disorders; Neuroimaging; Psychosis; Visual hallucinations