Modeling visuospatial perception in neglect patients.
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.
Ditterich
Jochen
J
Center for Sensorimotor Research, Department of Neurology, Ludwig-Maximilians University, Munich, Germany. jd@heidegger.rprc.washington.edu
Keller
Ingo
I
Eggert
Thomas
T
Straube
Andreas
A
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D006801:Humans; D008875:Middle Aged; D008959:Models, Neurological; D010468:Perceptual Disorders / Q000503:physiopathology* / Q000523:psychology; D013028:Space Perception / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology