Line bisection and unilateral visual neglect in patients with neurologic impairment

TLDR

Unilateral visual neglect is a frequent sign in patients with nondominant hemisphere lesions, and while several assessment techniques exist, the line‑bisection test—used for over 70 years—has never been statistically validated. The line‑bisection test estimates the perceived center of a horizontal line, and when applied to individual patients it should be paired with complementary procedures such as symmetric drawings and the Memory‑for‑Designs Test. Our formal evaluation showed that, under specific conditions, line‑bisection performance discriminates between right‑hemisphere lesion patients, diffuse‑lesion patients, left‑hemisphere lesion patients, and healthy controls.

Abstract

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.