Modeling visuospatial perception in neglect patients

Abstract.

 The spatial distortion hypothesis is one of several theories that explain certain aspects of neglect in patients with right parietal lesions. To determine whether a distorted representation of space can account for the performance of neglect patients in different visuospatial tasks, we asked 26 neglect patients to: (1) bisect horizontal lines and (2) to compare the width of two horizontally aligned bars. A simple mathematical model compatible with the idea of a stationary distortion of represented space in egocentric coordinates explained the results of the line-bisection task. A second model that had basically the same structure and was compatible with the idea of a distorted egocentric representation based on a dynamic remapping of space approximated the size-comparison data. These results support the view that abnormalities observed in the line-bisection and size-comparison tasks are due to a distorted internal representation of the external world. Certain findings suggest that this distortion could be based on a dynamic mapping of space determined by the distribution of visuospatial attention.