Unilateral spatial neglect in AD - Significance of line bisection performance

Background: Unilateral spatial neglect has been rarely reported in patients with AD, although they often have right and left asymmetry of temporoparie tal dysfunction. Objective: To investigate if patients with AD would show u nilateral spatial neglect in the line bisection test, and to reveal the rel ationship between their neglect and the area of cerebral dysfunction. Metho d: Thirty-two patients with mild to moderate AD and 32 age-matched healthy control subjects underwent an extensive line bisection test. SPECT was also obtained for the patients. Results: Rightward bisection errors exceeded th e normal range in 25% of patients with AD. They exhibited greater rightward errors for the longer lines in the left hemispace than in the right hemisp ace, and with the right hand than with the left hand; this corresponds to t he characteristics of neglect seen after right hemisphere lesions. All pati ents who bisected 200 mm lines with errors over 10 mm showed disproportiona te lowering of performance IQ and asymmetric right hemisphere hypoperfusion , especially in the temporoparietal region. Seventy-five percent of the pat ients performed normally in the center presentation but erred slightly towa rd the body midline in the right and left hemispaces. Conclusion: Left unil ateral spatial neglect in mild to moderate AD may be rather common if teste d with the line bisection test. Rightward errors over 10 mm suggest right t emporoparietal dysfunction. In AD, three or more bisections of 200 mm lines in the center presentation are recommended for detection of neglect. Patie nts with AD but without neglect may have difficulty in shifting attention i nto the peripheral sector of the egocentric space.