Visual extinction in relation to visuospatial neglect after right-hemispheric stroke: quantitative assessment and statistical lesion-symptom mapping
- 1Cognitive Neurology Section, Institute of Neuroscience & Medicine (INM-3), Research Centre Jülich, Jülich, Germany
- 2Neurological Rehabilitation Centre Godeshöhe, Bonn, Germany
- 3Department of Neurology, University Hospital Cologne, Cologne, Germany
- Correspondence to Dr Simone Vossel, Cognitive Neurology Section, Institute of Neuroscience and Medicine (INM-3), Research Centre Jülich, Leo-Brandt-Str 5, 52425 Jülich, Germany;
- Received 14 July 2010
- Revised 6 November 2010
- Accepted 27 November 2010
- Published Online First 17 January 2011
Background Visual neglect and extinction are two common neurological syndromes in patients with right-hemispheric brain damage. Whether and how these two syndromes are associated or share common neural substrates is still a matter of debate.
Methods To address these issues, the authors investigated 56 patients with right-hemispheric stroke with a novel diagnostic test to detect extinction and neglect. In this computerised task, subjects had to respond to target stimuli in uni- and bilateral stimulation conditions with detection probabilities being assessed. A cluster-analytical approach identified 18 patients with neglect and 13 patients with extinction. Statistical lesion-symptom mapping analyses with measures for extinction and neglect were performed.
Results Extinction and neglect co-occurred in a subset of patients but were also observed independently from each other, thereby constituting a double dissociation. Lesions within the right inferior parietal cortex were significantly associated with the severity of visual extinction. Visuospatial neglect was related to damage of fronto-parietal brain regions, with parieto-occipital areas affecting line bisection and dorsal fronto-parietal areas affecting cancellation task performance, respectively.
Conclusion Quantifying lesion-induced symptoms with this novel paradigm shows that extinction and neglect are dissociable syndromes in patients with right-hemispheric stroke. Furthermore, extinction and neglect can be related to differential neural substrates, with extinction being related to focal brain damage within the right inferior parietal cortex.
Competing interests None.
Ethics approval Ethics approval was provided by the Ethics Committee of the Medical Faculty of the University of Cologne.
Provenance and peer review Not commissioned; externally peer reviewed.