DIRECTIONAL HYPERATTENTION IN TACTILE NEGLECT WITHIN GRASPING SPACE

This study was motivated by the fact that unilateral neglect, an imped iment to progress in patient rehabilitation, is often reported to occu r in a wider area of space than that usually assessed in clinical sett ings. Neglect within ''grasping space'' (Halligan & Marshall, 1991; Ko lb & Whishaw, 1990) was assessed via two search tasks: one in which se arch was guided by visual information and the other in which search wa s guided by tactile information. The performance of 10 left brain-dama ged patients (LED) and 20 right brain-damaged patients, 10 of whom sho wed left visual neglect (RBD+) while 10 did not (RBD-), was compared w ith that of age-matched controls. The visual search task confirmed the clinical diagnoses of unilateral visual neglect. On the tactile test, both RED groups showed reduced search within the left hemispace, alth ough this was a particularly strong feature of the performance of RBD patients. Furthermore, this reduced leftwards exploration in RBD+ pat ients was associated with an increased frequency of repetitions made w ithin the right hemispace, as had also been noted in some of these pat ients on conventional visual star cancellation. Results are discussed in relation to hyperattentional theories of directional spatial neglec t.