The effect of cueing on unilateral neglect.

Heilman and Valenstein recently failed to reduce unilateral neglect, assessed by a line bisection task, by cueing patients to attend to their neglected field. Cueing was accomplished by placing letters at both ends of the line and instructing subjects to identify either the right or left hand letter prior to bisecting the line. The present experiments tested whether this failure to improve neglect occurred because patients were presented with competing stimuli in their neglected and non-neglected fields. Five patients with unilateral neglect and hemianopia took part in two experiments. The results showed a marked decrease in neglect when subjects were cued and forced to report stimuli in their neglected field. This occurred even when there was a competing stimulus in the non-neglected field. However, in the absence of forced report requirements, patients oriented to stimuli in the non-neglected field. The results are interpreted as a failure of patients with unilateral neglect to orient automatically to the side of space contralateral to the lesion, though processes governing the conscious orienting of attention are intact.