Objektbisektion bei Neglect

In bisection tasks, manipulations of the figural shape modulate the task performance of patients with left visuo-spatial neglect: patients bisect squares or round figures more accurately than ordinary lines. This group study with 11 neglect patients (and 13 neurological healthy controls) investigated whether a continuous or categorical modulation of the horizontal displacement can be observed in the line/object bisection task when the extension of one dimension of a two-dimensional object is parametrically manipulated. Therefore rectangles or ellipses were compressed in either the horizontal or vertical dimension while the other dimension was held constant. The objects with the strongest compression almost looked like a line. The task was either to bisect the figure or to mark the midpoint of it with a dot. The results are consistent with previous reports about figural modulation. In comparison with controls, neglect patients showed a significant rightward displacement of the bisection mark. Moreover, the patients showed better results when the two-dimensional features of the stimuli were more salient than when the stimuli were more similar to horizontal lines. The results are not in line with an abrupt, categorical transition from object-based attention to global visuo-spatial orienting because bisection performance decreased continuously with the gradual reduction of two-dimensional stimulus features. This suggests that object-based attentional mechanisms may operate in addition to space-based attention. Interestingly, ellipses were bisected more accurately than rectangles. One explanation for the latter finding is that the ellipses’ largest vertical distance is exactly its geometrical midpoint and that the patients may have implicitly used this information to improve task performance. Furthermore, larger forms induced relatively larger rightward displacement than smaller ones. Smaller objects may decrease the attention to a smaller focal area in comparison to larger objects.

Grantor dc:publisher

Publikationsserver der RWTH Aachen University

Year dc:date

2007

Author dc:creator

• Versin, Tobias

Contributors dc:contributor

• Willmes-von Hinckeldey, Klaus

• info:eu-repo/classification/ddc/610
• Medizin
• Neglect
• Objekte
• Bisektionsaufgabe
• Gruppenstudie
• group study
• objects
• bisection task

Statement dc:rights

• info:eu-repo/semantics/openAccess

Language dc:language

ger

Identifier

https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-114801%22

OAI record oai:identifier

https://publications.rwth-aachen.de/oai2d?verb=GetRecord&metadataPrefix=oai_dc&identifier=oai%3Apublications.rwth-aachen.de%3A52588