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Reality monitoring and visual hallucinations in Parkinson's disease

Barnes, James and Boubert, Laura and Harris, J. and Lee, A. and David, Anthony S. (2003) Reality monitoring and visual hallucinations in Parkinson's disease. Neuropsychologia, 41 (5). pp. 565-574. ISSN 0028-3932

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Official URL: http://dx.doi.org/10.1016/S0028-3932(02)00182-3


Between 8 and 40% of Parkinson disease (PD) patients will have visual hallucinations (VHs) during the course of their illness. Although cognitive impairment has been identified as a risk factor for hallucinations, more specific neuropsychological deficits underlying such phenomena have not been established. Research in psychopathology has converged to suggest that hallucinations are associated with confusion between internal representations of events and real events (i.e. impaired-source monitoring). We evaluated three groups: 17 Parkinson's patients with visual hallucinations, 20 Parkinson's patients without hallucinations and 20 age-matched controls, using tests of visual imagery, visual perception and memory, including tests of source monitoring and recollective experience. The study revealed that Parkinson's patients with hallucinations appear to have intact visual imagery processes and spatial perception. However, there were impairments in object perception and recognition memory, and poor recollection of the encoding episode in comparison to both non-hallucinating Parkinson's patients and healthy controls. Errors were especially likely to occur when encoding and retrieval cues were in different modalities. The findings raise the possibility that visual hallucinations in Parkinson's patients could stem from a combination of faulty perceptual processing of environmental stimuli, and less detailed recollection of experience combined with intact image generation.

Item Type:Article
Uncontrolled Keywords:Visual hallucinations, Parkinson's disease, Reality monitoring
Research Community:University of Westminster > Social Sciences, Humanities and Languages, School of
University of Westminster > Electronics and Computer Science, School of
ID Code:1458
Deposited On:05 May 2006
Last Modified:15 Oct 2009 15:37

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