Anatomical correlates of visual and tactile extinction in humans: a clinical CT scan study.

Vallar, Giuseppe; Rusconi, Maria Luisa; Bignamini, Lorenzo; Geminiani, Giuliano; Perani, Daniela

doi:10.1136/jnnp.57.4.464

Cited by 181 publications

(78 citation statements)

References 40 publications

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“…12,14,15,[27][28][29] The observation of a double dissociation of the 2 phenomena has led to a suggestion contrasting the view outlined here, namely to the suggestion of distinct anatomo-functional systems underlying both extinction and neglect. [11][12][13]30 Supporting anatomical evidence for this latter view derived from a recent study comparing the typical lesion location in patients with visual extinction and in patients with spatial neglect. 31 The authors observed closely related but anatomically distinct areas of brain damage in the 2 groups.…”

Section: Discussionmentioning

confidence: 95%

Incidence of Visual Extinction After Left Versus Right Hemisphere Stroke

Becker

Karnath

2007

Stroke

142

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Background and Purpose-Generally it is accepted that spatial neglect occurs predominantly after stroke of the human right hemisphere. In contrast, it remained controversial whether extinction follows the same hemispheric asymmetry. The opinion prevails that the laterality of visual extinction is not as pronounced as it is for spatial neglect. Methods-To directly compare the incidence of the 2 disorders within the same sample, spatial neglect and visual extinction were investigated during a 1-year period in 83 consecutively admitted patients with unilateral right or left hemisphere stroke. Results-The incidence of visual extinction and of spatial neglect was not significantly different, neither after left hemisphere (2.4% neglect; 4.9% extinction) nor after right hemisphere (26.2% neglect; 24.3% extinction) stroke. Conclusions-Visual extinction seems to be as asymmetrically associated with the human right hemisphere as is spatial neglect. (Stroke. 2007;38:3172-3174.)Key Words: brain damage Ⅲ clinical neurology Ⅲ cognitive impairment Ⅲ human Ⅲ neuropsychology Ⅲ spatial neglect Ⅲ visual extinction S patial neglect is a lateralized disorder with a characteristic failure to explore or react to stimuli presented in contralesional space. 1 Visual extinction, however, is a failure to detect a contralesional target in the presence of a competing ipsilesional stimulus. In contrast to neglect, extinction is apparent only when 2 stimuli compete for the subject's attention.Generally it is accepted that spatial neglect occurs predominantly after disruption of the human right hemisphere. [2][3][4][5][6][7][8][9] The disorder seems to be as asymmetrically represented in the right hemisphere, as are language functions in the human left hemisphere. In contrast, it remained controversial whether extinction follows the same hemispheric asymmetry as spatial neglect. In the literature, the opinion prevails that the laterality of visual extinction is not as pronounced as it is for spatial neglect. It has been suggested that the association with damage of the right hemisphere is much weaker in visual extinction than in spatial neglect. 10 -14 However, the empirical basis underlying this assumption is weak. Whereas the asymmetrical representation has been frequently demonstrated for spatial neglect, to our knowledge only very few studies investigated hemispheric lateralization for visual extinction by comparing directly right-side and left-side stroke patients. 4,15 Moreover, their results remained controversial. Although Odgen 15 found a preponderance of extinction after left brain damage (16% with left versus 6% with right brain damage), Stone et al 4 reported the opposite pattern (2% after left versus 23% after right brain damage).The controversial results could be attributable to the fact that the studies included patients with different etiologies (tumor/ stroke) or used different clinical methods/cut-off scores for evaluation.The present study aimed to reinvestigate the question whether visual extinction follows the same hemisph...

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Section: Discussionmentioning

confidence: 95%

Incidence of Visual Extinction After Left Versus Right Hemisphere Stroke

Becker

Karnath

2007

Stroke

142

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“…Finally, the anatomical correlates of extinction to double simultaneous stimulation in right-braindamaged patients do not entirely overlap with those of neglect. Subcortical and primary sensory regions are more frequently involved, with a relative sparing of inferiorposterior parietal cortex [42]. This differential lesion pattern suggests that the two disorders, which may occur in isolation, have discrete underlying pathological mechanisms.…”

Section: Trends In Cognitive Sciencesmentioning

confidence: 99%

Spatial cognition: evidence from visual neglect

Halligan

Fink

Marshall

et al. 2003

Trends in Cognitive Sciences

503

274

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Recent work on human attention and representational systems has benefited from a growing interplay between research on normal attention and neuropsychological disorders such as visual neglect. Research over the past 30 years has convincingly shown that, far from being a unitary condition, neglect is a protean disorder whose symptoms can selectively affect different sensory modalities, cognitive processes, spatial domains and coordinate systems. These clinical findings, together with those of functional neuroimaging, have increased knowledge about the anatomical and functional architecture of normal subsystems involved in spatial cognition. We provide a selective overview of how recent investigations of visual neglect are beginning to elucidate the underlying structure of spatial processes and mental representations.Once considered a unitary syndrome, it is now accepted that visuospatial neglect results from the interplay of damage to several different cognitive processes [1,2]. Even within such relatively simple tasks as copying or spontaneous drawing, patients show many qualitatively distinct patterns of omission and distortion in 'left' space [3].Deficits of attention, intention, global-local processing, spatial memory and mental representation can all contribute to the clinical picture of neglect, which accordingly cannot be traced back to the disruption of a single supramodal process [1,4]. Many of the symptoms traditionally ascribed to left neglect share little in common other than a contra-lesional gradient of increasing impairment, with comparatively well -preserved performance on the ipsilesional (right) side of space [1,5].Although characterising and remediating the clinical condition [1,2,5] are clearly crucial, the primary interest for cognitive neuroscience is how conditions such as visual neglect can inform existing cognitive theory and functional anatomy. That an abnormal bias towards one side of space can exist in the absence of contralateral peripheral sensory or motor loss (e.g. visual field losses or hemi-paralysis) suggests that impairment to higher level processes must be involved. The standard approach taken by cognitive neuropsychology characterises complex mental processes as information-processing systems with separate but interconnected components. Some of the informationprocessing stages involved in visual object recognition (see Fig. 1) illustrate the potential levels and links where lateralised deficits can arise after brain damage.This model charts the processing routes from preattentive assignment of simple structural features (i.e. without the need for focused attention and conscious awareness) to post-attentional integration of local and global processing (involving selective attention and conscious awareness) and the assignment of relevant spatial frames of reference prior to recognition and naming.

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“…(Note that although the Colavita effect has only been demonstrated using audiovisual displays, there is no theoretical reason that it should not extend to the visual-tactile modality pairing as well; see Gallace, Krings, Koppen, & Spence, 2007. ) In other words, visual stimuli might, at least in part, dominate over the judgments of the number of stimuli comprising the bimodal displays, or rather the simultaneous presentation of visual stimuli might to some extent extinguish a participant's awareness of the tactile stimuli (see Vallar, Rusconi, Bignamini, Geminiani, & Perani, 1994;Vuilleumier & Rafal, 2000).…”

Section: Tactilementioning

confidence: 99%