Attenuation of perceptual asymmetries in patients with early-onset schizophrenia: Evidence in favour of reduced hemispheric differentiation in schizophrenia?

Bellgrove, MA, Collinson, S, Mattingley, JB, Pantelis, C, Fitzgerald, PB, James, AC and Bradshaw, JL (2004) Attenuation of perceptual asymmetries in patients with early-onset schizophrenia: Evidence in favour of reduced hemispheric differentiation in schizophrenia?. Laterality, 9 1: 79-91. doi:10.1080/13576500244000319


Author Bellgrove, MA
Collinson, S
Mattingley, JB
Pantelis, C
Fitzgerald, PB
James, AC
Bradshaw, JL
Title Attenuation of perceptual asymmetries in patients with early-onset schizophrenia: Evidence in favour of reduced hemispheric differentiation in schizophrenia?
Journal name Laterality   Check publisher's open access policy
ISSN 1357-650X
Publication date 2004-01-01
Sub-type Article (original research)
DOI 10.1080/13576500244000319
Volume 9
Issue 1
Start page 79
End page 91
Total pages 13
Place of publication Hove
Publisher Psychology Press
Language eng
Abstract Lateral biases in visual perception have been demonstrated in normal individuals and in patients with unilateral brain lesions. It has been suggested that the absence of structural and functional asymmetries in schizophrenia could be due to a failure in lateralisation that may be most pronounced in those patients whose illness onset is at an early age. Here we examined lateral biases in patients with schizophrenia of an early onset (N = 21) and a late onset.(N = 19), and their respective age-matched control groups, using the greyscales task, a sensitive measure of asymmetries in visual processing. The stimuli consisted of two rectangles, one above the other, shaded in opposite directions and matched overall for darkness. Participants judged which of the two rectangles looked darker overall. Previous studies using this task in healthy participants have reported a reliable bias, such that the rectangle with the darker end on the left is selected preferentially. Whereas the late-onset patients in this study exhibited a perceptual bias of similar direction and magnitude to that of controls, this was not the case for the early-onset patients, who exhibited significantly less bias than their control group. The reduced perceptual bias seen in the early-onset group, but not the late-onset group, suggests an attenuation of right hemisphere mechanisms dedicated to processing vistiospatial information. The attenuated perceptual asymmetry in the early-onset group only may be consistent with the view that (i) an earlier illness onset reflects a greater loss of hemispheric differentiation and (ii) reduced functional asymmetries in the early-onset group are a manifestation of a failure to allocate functions to one or the other hemisphere.
Keyword Psychology, Multidisciplinary
Psychology, Experimental
Line Bisection
Attention
Dysfunction
Task
Overactivation
Performance
Neglect
Q-Index Code C1

Document type: Journal Article
Sub-type: Article (original research)
Collections: Excellence in Research Australia (ERA) - Collection
Queensland Brain Institute Publications
 
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Citation counts: TR Web of Science Citation Count  Cited 9 times in Thomson Reuters Web of Science Article | Citations
Scopus Citation Count Cited 9 times in Scopus Article | Citations
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Created: Tue, 14 Aug 2007, 00:06:53 EST