Spatial, selective and sustained attention to motion in a unilateral parietal patient with remediated neglect : a case study using multiple object tracking with infrared eye-tracking pupillometry

• Main Author: Lee, Anee Karin
• Format: Dissertation
• Language: English

Patients demonstrating a syndrome called unilateral neglect will often show a striking deficit in directing attention to the visual space contralateral to the site of cortical damage, or lesion. Once unilateral neglect has remediated, some neglect patients continue to demonstrate visual extinction, in which impairments in the allocation of attention appear only in the presence of competing stimuli. In this study, a relatively novel methodology, multiple object tracking (MOT) paired with eye-tracking and pupillometry, was used to quantify attention to motion in a parietal patient with remediated unilateral neglect. Our patient LE could select and track a single target from a field of identical distractors, but this selective attention mechanism differed from that of normal age-matched controls. LE also had significantly altered cognitive load capacity as well as sustained attention in both hemifields, thereby indicating a non-lateralized impairment of attention. Previous studies show that patients with extinction have performance that is severely impaired in the contralesional field, and slightly attenuated in the ipsilesional field. Contrary to previous findings, our results suggest that sustained attention to motion can be more severely impaired in the ipsilesional than in the contralesional hemifield, and also be affected altitudinally. Most surprising was the reduced performance in the controls when attending the left hemifield in the presence of competing stimuli in the right hemifield. In conclusion, studying attention with MOT in conjunction with eye-tracking and pupillometry offers a unique possibility to further characterize specific spatial, selective, and sustained attentional functions in patients as well as in healthy aging participants.