Line bisection and unilateral visual neglect in patients with neurologic impairment.

Unilateral visual neglect is a common symptom or sign in patients with lesions of the nondominant hemisphere. Several techniques have been used to demonstrate visual neglect. One such technique--asking a patient to bisect a horizontal line and expecting an estimate of center away from the side neglected--has been used for over 70 years but has not been statistically evaluated. We conducted a formal evaluation of this method and found that under special conditions, line-bisection performance can discriminate between patients with right-hemisphere lesions and patients with diffuse lesions, patients with left-hemisphere lesions, and hospital controls. When used to investigate visual neglect in an individual patient, the line-bisection test should be given in conjunction with other complementary procedures such as symmetric drawings and the Memory-for-Designs Test.