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Neglect after right hemisphere stroke: a smaller floodlight for distributed attention
A M Barrett1, D Q Beversdorf, G P Crucian
1Department of Veterans Affairs Medical Center and the Department of Neurology, University of Florida, College of Medicine, Gainesville 32610-0236, USA.
Neurology
|October 22, 1998
Summary
Patients with right hemisphere stroke and neglect show impaired spatial attention. Their performance worsened with larger gaps, suggesting a defective attentional floodlight, not just a spotlight issue.
Area of Science:
- Cognitive Neuroscience
- Neuropsychology
- Visual Attention
Background:
- Visual attention operates via an attentional spotlight for focused tasks.
- Spatially distributed attention may utilize an attentional floodlight.
- Neglect following right hemisphere stroke is linked to attentional spotlight deficits.
Purpose of the Study:
- To investigate potential defects in the attentional floodlight mechanism.
- To determine if right hemisphere stroke-related neglect impacts spatially distributed attention.
Main Methods:
- A line decision task was employed, assessing the perception of two line segments separated by a gap.
- The area of the gap was manipulated to vary the spatial extent of attention required.
- Performance was compared between patients with right hemisphere stroke and neglect, and control groups (normal and left hemisphere-damaged).
Main Results:
- Patients with right hemisphere stroke and neglect demonstrated significantly poorer performance as the gap area increased.
- Performance of right hemisphere-damaged patients was not affected by the degree of line discontinuity.
- Control groups did not exhibit the same performance decline with increasing gap area.
Conclusions:
- The findings support the hypothesis of a defective attentional floodlight in patients with neglect after right hemisphere stroke.
- This suggests that neglect may involve impairments in spatially distributed attention, beyond focal attention deficits.