Grey scales uncover similar attentional effects in homonymous hemianopia and visual hemi-neglect

M.L.M. Tant, J.B.M. Kuks, A.C. Kooijman, F.W. Cornelissen, W.H. Brouwer

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Abstract

Multi-component models of visual hemi-neglect have postulated that visual hemi-neglect is characterised by various attentional deficits. A grey scales task has been developed to quantify the early. automatic. (perhaps obligatory) ipsilesional orienting of visual attention, frequently assumed as the first of these attentional deficits. Explanations for this attentional imbalance are Up until now mainly formulated in term,, of right hemisphere activation. This lateral attentional bias has also been demonstrated in controls, in whom it is expressed as a leftward perceptual asymmetry. We reproduced previous literature findings on a grey scales task. considering controls and neglect patients. Three patients with neglect showed an extreme ipsilesional lateral bias, This bias did not change during or after cognitive rehabilitation. Additionally, we presented this grey scale task to 32 patients with left- and right-sided homonymous hemianopia (HP). HP is the loss of sight in one visual hemi-field. The HH patients had no clinical signs of impaired lateralised attention. Results revealed that HH patients showed a similar ipsilesional bias. albeit to a lesser degree than in neglect. Left-sided HH patients presented a quantitatively similar, but qualitatively opposite bias than the right-sided HH patients. We suggest that sensory effects can be an alternative source of attentional imbalance, which can interact with the previously proposed (right) hemispheric effects. This suggests that the perceptual asymmetry in the rev scales task is not necessarily an indicator of impaired right hemisphere attention. It rather suggests a pattern of functional cerebral asymmetry, which can also be caused by asymmetric sensory input. (C) 2002 Elsevier Science Ltd. All rights reserved.

Original languageEnglish
Article numberPII S0028-3932(01)00197-X
Pages (from-to)1474-1481
Number of pages8
JournalNeuropsychologia
Volume40
Issue number8
DOIs
Publication statusPublished - 2002

Keywords

  • attentional imbalance
  • perceptual bias
  • hemispheric specialisation
  • laterality
  • LINE BISECTION
  • PERCEPTUAL ASYMMETRIES
  • MOTION SENSATION
  • STROKE PATIENTS
  • BRAIN-DAMAGE
  • ORIENTATION
  • JUDGMENTS
  • RECOVERY
  • STIMULI
  • BIAS

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