Pointing and bisection in open and closed loop reaching in patients with hemispatial neglect

Abstract

It is well established that patients with hemispatial neglect present severe visuospatial impairments, but studies that have directly investigated the visuomotor control in these patients have revealed diverging results, some pointing to relatively spared visuomotor function. The present study compared the performance of 8 patients with hemispatial neglect and 10 without the disorder after right hemisphere stroke and 10 age-matched controls. Subjects were asked to point either directly towards targets or in the middle of two targets, both with and without visual feedback of the hand and target during movement. No specific impairments were observed for the neglect patients on either timing, speed and end-point accuracy measures for any of the conditions. Despite the failure of our neglect patients to react to stimuli on the contralesional side of space when assessed with paper and pencil tests, we did not find any specific deviations in their movements. Our results suggest that the perceptual distortions present in patients with neglect do not influence their performance on pointing tasks with or without visual feedback of their hand, supporting the view that such patients code spatial parameters for action veridically.

Footnotes

 This work was funded by a grant (SFRH/BD/23230/2005) from the Portuguese Foundation for Science and Technology to S Rossit.