title: Validation of diagnostic criteria for apathy in Parkinson's disease.
abstract: BACKGROUND
  Apathy is a common neuropsychiatric syndrome in Parkinson's Disease (PD) that affects quality of life. Research into apathy has been hampered by a lack of broadly accepted diagnostic criteria. Recently, diagnostic criteria for apathy in neuropsychiatric disorders have been proposed, which to date have not been validated in PD.
  
  
  OBJECTIVE
  To validate the proposed diagnostic criteria for apathy in PD.
  
  
  METHODS
  In a cross-sectional study, outpatients with PD visiting a movement disorders clinic underwent a protocolized assessment of motor function, activities of daily living (ADL), cognition and mood. In addition, the diagnostic criteria for apathy were administered as well as two apathy rating instruments: the Lille Apathy Rating Scale (LARS) and the apathy section of the Neuropsychiatric Inventory (NPI).
  
  
  RESULTS
  Of the included patients 17.2% were diagnosed with apathy according to the criteria. Acceptability and internal consistency of the criteria was good, as was the concurrent validity with the LARS and apathy section of the NPI. Discriminant validity of the criteria with depression was moderate to good. All domains of criterion B (behavior, cognition, emotion) contributed to the diagnosis of apathy, of which reduced goal-directed behavior was the most frequently observed symptom.
  
  
  CONCLUSIONS
  The recently proposed diagnostic criteria for apathy are useful in clinical practice and in research with PD patients with and without cognitive impairment.
authors.affiliation: Department of Psychiatry, Maastricht University Medical Centre, PO Box 5800, 6202 AZ Maastricht, The Netherlands.
authors.forename: Rosa L
authors.initials: RL
authors.lastname: Drijgers
authors.forename: Kathy
authors.initials: K
authors.lastname: Dujardin
authors.forename: Jennifer S A M
authors.initials: JS
authors.lastname: Reijnders
authors.forename: Luc
authors.initials: L
authors.lastname: Defebvre
authors.forename: Albert F G
authors.initials: AF
authors.lastname: Leentjens
mesh_terms: D000368:Aged; D001007:Anxiety / Q000175:diagnosis / Q000523:psychology; D057565:Apathy / Q000502:physiology*; D003071:Cognition / Q000502:physiology; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D039721:Diagnostic and Statistical Manual of Mental Disorders; D004644:Emotions / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D015588:Observer Variation; D010300:Parkinson Disease / Q000150:complications / Q000175:diagnosis* / Q000523:psychology*; D015203:Reproducibility of Results