title: Patient and Informant Views on Visual Hallucinations in Parkinson Disease.
abstract: OBJECTIVE
  Visual hallucinations (VHs) are a very personal experience, and it is not clear whether information about them is best provided by informants or patients. Some patients may not share their hallucinatory experiences with caregivers to avoid distress or for fear of being labeled insane, and others do not have informants at all, which limits the use of informant-based questionnaires. The aim of this study was to compare patient and caregiver views about VHs in Parkinson disease (PD), using the North-East Visual Hallucinations Interview (NEVHI).
  
  
  METHODS
  Fifty-nine PD patient-informant pairs were included. PD patients and informants were interviewed separately about VHs using the NEVHI. Informants were additionally interviewed using the four-item version of the Neuropsychiatric Inventory. Inter-reliability and concurrent validity of the different measures were compared.
  
  
  RESULTS
  VHs were more commonly reported by patients than informants. The inter-rater agreement between NEVHI-patient and NEVHI-informant was moderate for complex VHs (Cohen's kappa = 0.44; 95% confidence interval [CI]: 0.13-0.75; t = 3.43, df = 58, p = 0.001) and feeling of presence (Cohen's kappa = 0.35; 95% CI: 0.00-0.70; t = 2.75, df = 58, p = 0.006), but agreement was poor for illusions (Cohen's kappa = 0.25; 95% CI: -0.07-0.57; t = 2.36, df = 58, p = 0.018) and passage hallucinations (Cohen's kappa = 0.16; 95% CI: -0.04-0.36; t = 2.26, df = 58, p = 0.024).
  
  
  CONCLUSIONS
  When assessing VHs in PD patients, it is best to rely on patient information, because not all patients share the details of their hallucinations with their caregivers.
authors.affiliation: Gerontechnology & Rehabilitation Group, University of Bern, Bern, Switzerland.
authors.forename: Prabitha
authors.initials: P
authors.lastname: Urwyler
authors.affiliation: Gerontechnology & Rehabilitation Group, University of Bern, Bern, Switzerland; ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland.
authors.forename: Tobias
authors.initials: T
authors.lastname: Nef
authors.affiliation: Gerontechnology & Rehabilitation Group, University of Bern, Bern, Switzerland; Perception and Eye Movement Laboratory, Departments of Neurology and Clinical Research, University Hospital Inselspital, University of Bern, Bern, Switzerland.
authors.forename: René M
authors.initials: RM
authors.lastname: Müri
authors.affiliation: Institute for Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom.
authors.forename: Alison
authors.initials: A
authors.lastname: Killen
authors.affiliation: Institute for Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom; Northumberland, Tyne & Wear NHS Foundation Trust, Bensham Hospital, Gateshead, United Kingdom.
authors.forename: Daniel
authors.initials: D
authors.lastname: Collerton
authors.affiliation: Institute for Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom.
authors.forename: David
authors.initials: D
authors.lastname: Burn
authors.affiliation: Institute for Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom.
authors.forename: Ian
authors.initials: I
authors.lastname: McKeith
authors.affiliation: Gerontechnology & Rehabilitation Group, University of Bern, Bern, Switzerland; University Hospital of Old Age Psychiatry, University of Bern, Bern, Switzerland. Electronic address: urs.mosimann@gef.be.ch.
authors.forename: Urs Peter
authors.initials: UP
authors.lastname: Mosimann
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D017028:Caregivers / Q000523:psychology*; D003430:Cross-Sectional Studies; D005260:Female; D006212:Hallucinations / Q000150:complications* / Q000453:epidemiology / Q000523:psychology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000150:complications* / Q000453:epidemiology / Q000523:psychology*; D015995:Prevalence; D011569:Psychiatric Status Rating Scales; D011594:Psychometrics; D057566:Self Report / Q000592:standards*; D006113:United Kingdom / Q000453:epidemiology
keywords: Parkinson disease; Visual hallucinations; inter-rater agreement