THROUGH A LOOKING GLASS. A NEW TECHNIQUE TO DEMONSTRATE DIRECTIONAL HYPOKINESIA IN UNILATERAL NEGLECT

Abstract

SUMMARY A line cancellation task was performed by right brain-damaged patients with neglect in two response conditions. The task was presented either in normal view or through a 90° angle mirror with direct view prevented. The latter decouples the direction of visual attention and of arm movement. In the mirror condition, 4 of 18 patients cancelled lines only in right hemispace which means that they directed their visual attention to the left but failed to execute movements towards contralateral hemispace—what has been termed directional hypokinesia. In contrast, 10 patients cancelled lines only in left hemispace in the mirror condition, which accords better with attention-representation deficit hypotheses. Our results support a division of the neglect syndrome according to whether perceptual or premotor deficits are predominant.