Right-sided cueing can ameliorate left neglect

Abstract

We report three cases of left visuospatial neglect after right hemisphere injury; the patients differ in severity and time post-insult. In the first experiment, all three patients showed a significant impairment on horizontal line bisection but were differentially sensitive to focal left-sided cueing in this task. All three were considerably more accurate when requested to mark the centre of squares whose horizontal extent was identical to that of the previously employed lines. In the second experiment, two of the three patients also showed significant improvements on horizontal line bisection when a vertical line was positioned at the right end of the horizontal line; for one of these patients, no such improvement took place when an identical vertical line was placed at the left end of the horizontal line. In the third experiment, we show that, for this latter patient, the extent of improvement is positively associated with the length of the vertical line in right space. The experiment also shows that marking a vertical extent on the right with two discrete colinear stimuli improves performance to an extent comparable to that given by the full line. We argue that cueing with a large vertical configuration in right space can increase the diameter of the “attentional spotlight” within which the stimulus configuration is perceived. The results have clear implications for the remediation of neglect.