Two techniques for the assessment of line bisection in visuo-spatial neglect: a single case study.

A patient with severe left neglect after surgery for basilar aneurysm is described. Her performance on freehand line bisection was compared and contrasted with the results from computerised visual display unit (VDU) presentation. In the latter format the patient makes her transections with a "mouse" controlled cursor arrow. The technique provides rigorous control over starting position and also allows self-corrections. Although left neglect persisted at longer line lengths under these conditions, the magnitude of the effect decreased significantly; the cross-over point where right displacements change to left displacements as a function of line length also varied between the three conditions (freehand, left and right computer-start).