The Japanese journal of neuropsychology

Full Text of this Article
in Japanese PDF (97K)

ArticleTitle	Effects of space and frame on line bisection performance of patients with unilateral spatial neglect
Language	J
AuthorList	Naomi Nakano¹⁾, Sumio Ishiai¹⁾, Yasumasa Koyama¹⁾, Keiko Seki²⁾, Hajime Hirabayashi³⁾, Koichiro Inaki³⁾
Affiliation	1) Department of Rehabilitation, Tokyo Metropolitan Institute for Neuroscience 2) Faculuty of Health Science, Kobe University School of Medicine 3) Departement of Clinical Psychology, Kakeyu Hospital Rehabilitation Center
Publication	Japanese Journal of Neuropsychology: 18 (3), 200-207, 2002
Received	Jan 5, 2002
Accepted	Apr 5, 2002
Abstract	Line bisection task is commonly used to evaluate patients with unilateral spatial neglect. We examined line bisection performance of 47 patients with left neglect under two conditions of line presentation. 1) The line bisection subtest of the Behavioural inattention test (BIT), in which a line 204 mm long is printed in each of the upper right, center, and lower left positions of the test sheet. 2) The bisection of 200-mm lines that were individually presented in the left, center, and right locations relative to the body midline. The duration of the subjective midpoint was measured from the objective midpoint, and the percentage deviation was calculated according to Shenkenberg et al (1980) to compare the results of the two tasks. The mean percentage deviation for each of the left, center, and right lines was greater in the BIT subtest than in the bisection of single lines. In the BIT subtest, the mean percentage deviation was greater for the left than for the center line, and for the center than for the right line. In the bisection of single lines, the subjective midpoint was deviated more to the right for the center than the right line. However, the mean percentage deviation was not significantly different between the left and center presentations. The results indicate that the line bisection performance of patients with neglect was influenced by the location of lines relative to the body midline as well as the frame in which the lines were presented. In the BIT line bisection subtest, most patients bisected the upper right, center, and lower left lines in this order. Accordingly, the bisection of the left and center lines may have been affected by the bisected line(s) that was located to their right side, which might be due to over-attention to the right-side stimulus, disengagement of attention from the formerly marked subject midpoint, or both. In the bisection of single lines, the presentation of the test sheet in the left hemispace may have acted as cueing to that side and reduced the rightward bisection errors. In the group of healthy control subjects, there was little effect of the condition of line presentation on their bisection performance, and the normal range obtained from them was similar in the BIT subtest and the bisection of single lines. We consider that the BIT line bisection subtest is suitable for clinical diagnosis of neglect, as it enhances the rightward errors of patients with neglect and the spatial effect of line presentation.
Keywords	unilateral spatial neglect, line bisection test, Behavioural inattention test (BIT), frame, space