NEGLECT AFTER RIGHT-HEMISPHERE STROKE - A SMALLER FLOODLIGHT FOR DISTRIBUTED ATTENTION

Objective: To learn whether there was a defect in an attentional flood light. We used a line decision task for which subjects had to decide i f two line segments separated by a gap were one line or two parallel L ines. We varied the area of the gap and, therefore, the area over whic h subjects needed to spread attention to perform the task correctly. B ackground: Visual tasks requiring focused attention use an attentional spotlight. Other visual tasks requiring spatially distributed attenti on may require a floodlight. Neglect after right hemisphere stroke can be associated with a defect in the attentional spotlight. Results and Conclusions: Two patients with neglect after right hemisphere stroke performed more poorly than normal control subjects and left hemisphere -damaged control subjects as the area of spread in the gap increased. Right hemisphere-damaged patients did not differ from control subjects ' performance on another visuospatial parameter-the degree of disconti nuity between the line segments. These results support a defective att entional floodlight in neglect.