Pupillographic findings in neglect

Objectives-Unilateral sensory neglect has been attributed to various defect s, including a hemispatial attention-arousal deficit. However, support for this hypothesis has only been indirect. Therefore, the purpose of this stud y was to further test the hemispatial attentional-arousal hypothesis by mea suring pupillary response as an index of arousal. Methods-There were two experimental subjects with neglect and six matched c ontrols. Stimuli (Arabic numbers) were presented on the right, left, and ce ntre of a screen. The subjects were asked to look at the number in the cent re, on the right, or left of the screen while their pupil diameter was meas ured. Results-Unlike the control subjects, the subjects with neglect, who were aw are of the left sided stimuli, did not show a pupillary dilatation when the y looked at the stimulus on the left. Conclusions-Although this study provides support for the hemispatial attent ion-arousal hypotheses of neglect, it does not preclude the possibility tha t other mechanisms may also be important.