Focusing attention on the visual field border: Short-term and long-term effects of visuo-spatial cueing in patients with visual field defects

Abstract

Numerous experiments in cognitive psychology have shown that spatial cueing has beneficial effects on visual information processing in normally-sighted subjects. In two combined studies, we investigated whether a visuo-spatial cue also improves visual perception in patients with visual field defects due to brain lesion. Short-term effects of visuo-spatial attention were studied in a sample of 23 patients performing conventional visual field tests and attention field tests, i.e. a campimetric procedure using a cueing paradigm specifically designed to help subjects direct the focus of attention on their visual field border. We found an increase of stimulus detection and a decrease of reaction times in valid trials, but there were also benefits in invalidly cued conditions due to an unspecific alerting influence of the cue. The extent of improvement was significantly correlated with the size of areas of residual vision in the attended area, i.e. patients with “soft” visual field borders showed a stronger benefit of attentional allocation. Long-term effects of attention were investigated in a training study with 19 patients. We compared conventional computer-based visual restitution training (VRT) and attention field training which combined systematic light stimulation and attentional cueing. Visual field training resulted in a highly significant visual field enlargement, and the implementation of a visuo-spatial cue changed the pattern of visual field recovery. Our findings indicate that visuo-spatial attention has short-term beneficial effects on visual perception of brain-lesioned patients, but it also influences long-term processes of neuronal plasticity resulting in more permanent benefits in the restitution of visual functions.