Visual hallucinations in the differential diagnosis of parkinsonism
- 1Neurology Department, Alfred Hospital, Melbourne, Victoria, Australia
- 2Van Cleef Roet Centre for Nervous Diseases, Monash University, Melbourne, Victoria, Australia
- Correspondence to Professor D R Williams, Van Cleef Roet Centre for Nervous Diseases, Alfred Hospital 7th Floor, Commercial Rd, Melbourne, Victoria 3004, Australia;
Contributors KB and DRW contributed equally to the concept, research, writing and editing of this manuscript.
- Received 17 July 2011
- Revised 4 October 2011
- Accepted 24 October 2011
- Published Online First 6 January 2012
Visual hallucinations (VH) occur commonly in Parkinson's disease (PD) and dementia with Lewy bodies (DLB) but are reported much less frequently in other neurodegenerative causes of parkinsonism, such as progressive supranuclear palsy, multiple system atrophy and corticobasal degeneration syndrome. This clinical sign may be helpful when considering the differential diagnosis of patients with parkinsonism. The observation that VH may be specific to Lewy body pathology probably reflects a greater vulnerability of the visual systems to PD and DLB neurodegeneration compared with other diseases. Topographic differences in pathology are probably the major factor producing VH in Lewy body diseases, rather than neurophysiological changes that are specific to α-synuclein protein accumulation. VH correlate with pathology in the limbic system and more specifically the amygdale that is frequently affected in PD and DLB but relatively preserved in other forms of parkinsonism often misdiagnosed as PD. In this review, the published frequencies of VH in these different conditions are compared to put into context the notion of VH as a clinical clue to underlying Lewy body pathology.
Competing interests None.
Provenance and peer review Commissioned; externally peer reviewed.
This is an open-access article distributed under the terms of the Creative Commons Attribution Non-commercial License, which permits use, distribution, and reproduction in any medium, provided the original work is properly cited, the use is non commercial and is otherwise in compliance with the license. See: http://creativecommons.org/licenses/by-nc/2.0/ and http://creativecommons.org/licenses/by-nc/2.0/legalcode.