SPATIAL HEMINEGLECT IN BACK SPACE

The subjective location of the mid-sagittal plane was assessed by a fr ee-field auditory localization task in the front and in the back half- spaces in 11 right brain-damaged patients with spatial hemineglect, 10 right brain-damaged patients without spatial hemineglect and 11 norma l control subjects. In patients with hemineglect the subjective mid-sa gittal plane was found to be displaced rightwards in both half-spaces. Both patients without hemineglect and controls, in contrast, made a m inor error and showed a greater displacement towards the left side in the back half-space. In four right brain-damaged patients the rightwar d displacement was confined either to the front, or to the back half-s pace. This pattern of impairment may be explained by a rightward, ipsi lesional, pathological translation of an egocentric coordinate system, rather than by a rotation around the vertical axis of the body.