Abnormal temporal dynamics of visual attention in spatial neglect patients.

WHEN we identify a visual object such as a word or letter, our ability to detect a second object is impaired if it appears within 400ms of the first1–5. This phenomenon has been termed the attentional blink or dwell time and is a measure of our ability to allocate attention over time (temporal attention). Patients with unilateral visual neglect are unaware of people or objects con-tralateral to their lesion6,7. They are considered to have a disorder of attending to a particular location in space (spatial attention)6–11. Here we examined the non-spatial temporal dynamics of attention in patients, using a protocol for assessing the attentional blink. Neglect patients with right parietal, frontal or basal ganglia strokes had an abnormally severe and protracted attentional blink. When they identified a letter, their awareness of a subsequent letter was significantly diminished for a length of time that was three times as long as for individuals without neglect. Our results demonstrate for the first time that visual neglect is a disorder of directing attention in time, as well as space.