The effect of hemispatial neglect on the perception of centre.
Highly variable bisection performance in neglect patients has been attributed to an increased 'zone of indifference'. The indifference zone indicates the discrepancy between two line lengths which are judged as equal in length. Following this argumentation, the central area of a line should be expanded in neglect patients. The present two experiments investigated for the first time the expansion of the central area using a modified version of the Landmark Task. The location of a central or asymmetrical bisection mark on a horizontal line had to be judged (centre/left/right). In both experiments neglect patients, unlike healthy and patient controls, showed clear deficits in judging the location of the mark correctly and tended to judge asymmetrical marks of up to 4 cm as centrally positioned. The results are in agreement with and provide the first clear evidence of an enlarged perceptual zone of indifference in patients with hemispatial visual neglect.
Olk
Bettina
B
Department of Psychology, University of British Columbia, 2136 West Mall, Vancouver BC, Canada V6T 1Z4. b.olk@iu-bremen.de
Wee
Joy
J
Kingstone
Alan
A
D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001288:Attention / Q000502:physiology; D002544:Cerebral Infarction / Q000150:complications / Q000503:physiopathology*; D006801:Humans; D007600:Judgment / Q000502:physiology*; D010468:Perceptual Disorders / Q000209:etiology / Q000503:physiopathology*; D012016:Reference Values; D012858:Size Perception / Q000502:physiology*; D013028:Space Perception / Q000502:physiology*; D013037:Spatial Behavior / Q000502:physiology