Is space representation distorted in neglect?

It has been argued that neglect of contralateral stimuli following brain da mage might be associated with either a compressed or an anisometric neural representation of space along the earth-horizontal axis. Two different mode ls have been put forward. One model proposes a uniform compression of subje ctive space, while the other envisages an expansion on one side of space an d a compression on the other. We tested these models by determining neglect patients' perception of spatial distances in the horizontal plane. The mod els differ concerning the expected degree of under- vs overestimation of di stances in the left and right hemispace. In the first experiment, patients were asked to position ten red LEDs equidistantly along a semicircle, which was located horizontally in front of them at eye level. A second experimen t compared the patients' subjective perception of short, medium and long di stances extending into left and right hemispace. We found no evidence for a ny compression or expansion, nor for anisometry along the earth-horizontal axis. These findings argue against a distortion of subjective space along t he horizontal axis in patients with neglect which could account for their f ailure to orient towards and to explore the contralesional parts of space. (C) 1998 Elsevier Science Ltd. All rights reserved.