Diminution and enhancement of visuo-spatial neglect with sequential trials.

We report three cases of visuo-spatial neglect after unilateral right hemisphere damage. Each patient undertook 100 sequential trials of line bisection. All patients were grossly impaired, placing their transections of the longer lines significantly to the right of true centre. When the trials were analysed in two consecutive halves, one patient showed only minimal differences in accuracy between the two blocks. One patient improved greatly on the second block, and one patient became significantly worse. The results are discussed in terms of differential "learning" and "fatigue" effects, and their clinical significance is outlined.