The Character-line Bisection Task: a new test for hemispatial neglect

Area of Science:

• Neuroscience
• Clinical Psychology
• Rehabilitation Medicine

Background:

• Hemispatial neglect is a failure to report or respond to stimuli in a spatial field.
• Conventional tests like line bisection and cancellation have limitations in sensitivity when used alone.
• A combined approach may improve the detection of unilateral neglect.

Purpose of the Study:

• To evaluate the sensitivity, reliability, and validity of the novel Character-line Bisection Task (CLBT).
• To determine if the CLBT, particularly its letter version, induces a greater rightward bias, reflecting left hemisphere activation.
• To compare the diagnostic performance of the CLBT against established neglect assessment tools.

Main Methods:

• Eighty patients with acute right hemisphere stroke and 81 controls performed the CLBT (Letter-line and Star-line subtests).
• Subjects also completed four conventional neglect tests: standard line bisection, line cancellation, Star Cancellation, and figure copying.
• Neglect presence was defined by a total score derived from all six tests, with CLBT performance analyzed for rightward bias.

Main Results:

• The CLBT induced a greater rightward bisection bias in both patients and controls compared to the standard solid-line bisection task.
• The Letter-line and Star-line tasks demonstrated the highest sensitivities (90.9% and 87.3%, respectively) in detecting neglect.
• The CLBT identified 50 and 48 patients with neglect, outperforming other conventional tests.

Conclusions:

• The Character-line Bisection Task (CLBT) exhibits superior sensitivity for detecting unilateral neglect compared to existing methods.
• The CLBT, by combining bisection and cancellation features, offers a more effective tool for diagnosing and quantifying spatial neglect.
• These findings support the clinical utility of the CLBT in neurological assessments following stroke.