Normalization of horizontal pseudoneglect following right, but not left, upper limb amputation.

OBJECTIVES

Subjects who have suffered limb amputations are known to have physiological alterations of their body's representation, or schema. Such changes of brain function might alter the right-left spatial allocation of attention. The goal of this study was to learn if, compared to normal subjects, limb amputees had alterations of right-left spatial attention.

METHODS

The subjects were veterans with amputation of one upper or lower limb. All subjects performed horizontal line bisections in their left, middle and right body-centered space.

RESULTS

Following right upper limb amputation, there appears to be a reduction of the normal left-sided bias (pseudoneglect) primarily for lines presented in the right body hemispace.

CONCLUSIONS

This amputation-induced alteration of attentional bias might be related to changes in the body schema, a compensatory strategy, or alterations of scanning patterns. Further studies are needed to reproduce these results and to learn the underlying brain mechanism.