Point localisation in patients with unilateral brain damage.

The ability to reproduce the position of points in a plane was examined by a copying test in a control group and in unilaterally brain damaged patients. The procedure was designed to minimise the influence of visual field defects and of spatial hemi-inattention on performance. Accuracy of of localisation and direction of errors were studied in each half of the plane. Analysis showed a greater impairment of localisation ability in the patients with right hemisphere disease; however, the performance of both hemispheric groups was characterised by a reduction of accuracy in half of the plane contralateral to the side of the lesion. Both hemispheric groups showed an abnormal direction of errors in the left half of the plane, but the two groups presented a different pattern of errors.