scholarly journals Biases in Attentional Orientation and Magnitude Estimation Explain Crossover: Neglect is a Disorder of Both

2005 ◽  
Vol 17 (8) ◽  
pp. 1194-1211 ◽  
Author(s):  
Mark Mennemeier ◽  
Christopher A. Pierce ◽  
Anjan Chatterjee ◽  
Britt Anderson ◽  
George Jewell ◽  
...  
Keyword(s):  
Magnitude Estimation ◽  
Normal Component ◽  
Line Bisection ◽  
Spatial Neglect ◽  
Length Estimation ◽  
On Line ◽  
Quantitative Changes ◽  
True Center ◽  
Necessary And Sufficient ◽  
Pattern Of Performance

Crossover refers to a pattern of performance on the line bisection test in which short lines are bisected on the side opposite the true center of long lines. Although most patients with spatial neglect demonstrate crossover, contemporary theories of neglect cannot explain it. In contrast, we show that blending the psychophysical construct of magnitude estimation with neglect theory not only explains crossover, but also addresses a quantitative feature of neglect that is independent of spatial deficits. We report a prospective validation study of the orientation/estimation hypothesis of crossover. Forty subjects (17 patients with and without neglect following unilateral brain injury and 23 normal controls) completed four experiments that examined crossover using line bisection, line bisection with cueing, and reproducing line lengths from both memory and a standard. Replicating earlier findings, all except one subject group exhibited crossover on the standard line bisection test, all groups showed a spontaneous preference to orient attention to one end of the lines, and all groups overestimated the length of short lines and underestimated long lines. Biases in attentional orientation and magnitude estimation are exaggerated in patients with neglect. The truly novel finding of this study occurred when, after removing the line from the bisection task, the direction of crossover was completely reversed in all subject groups depending on where attention was oriented. These findings are consistent with our hypothesis of crossover: (1) crossover is a normal component of performance on line bisection; (2) crossover results from the interplay of biases in attentional orientation and magnitude estimation; and (3) attentional orientation predicts the direction of crossover, whereas a disorder of magnitude estimation, not previously emphasized in neglect, accounts for the quantitative changes in length estimation that make crossover more obvious in neglect subjects. Paradoxically, we observed that the traditional line bisection test is suboptimal for exploring crossover because lines elicit spontaneous orientation responses from subjects that confound experimental manipulations of attention. We conclude that attentional orientation and magnitude estimation are necessary and sufficient to explain crossover and that bias in magnitude estimation is a core component of neglect.

Crossover is not a consequence of neglect: A test of the orientation/estimation hypothesis

2002 ◽  
Vol 8 (1) ◽  
pp. 107-114 ◽  
Author(s):  
MARK MENNEMEIER ◽  
ELSIE VEZEY ◽  
MELISSA LAMAR, ◽  
GEORGE JEWELL
Keyword(s):  
Brain Injury ◽  
Visual Inspection ◽  
Right Hemisphere ◽  
Line Bisection ◽  
Crossover Effect ◽  
Spatial Direction ◽  
Length Estimation ◽  
On Line ◽  
Left And Right ◽  
Pattern Of Performance

Most patients with neglect demonstrate a crossover effect on line bisection. Crossover refers to a pattern of performance in which long lines (>10 cm) are bisected ipsilateral to brain injury and short lines (<2 cm) are bisected contralateral to brain injury. Crossover bisections on short lines are of interest because they are not predicted by contemporary theories concerning neglect. However, we propose that the effect depends on two independent factors that normally influence bisection performance but are merely exaggerated in neglect—a tendency to overestimate the length of short lines and underestimate long lines and a tendency to orient attention preferentially in one spatial direction. We predicted that both patients with unilateral left and right hemisphere injury would demonstrate crossover on line bisection and that they would overestimate short lines and underestimate long lines upon direct visual inspection. Further, the 2 groups were predicted to demonstrate crossover in opposite directions owing to different lesion-induced biases in attentional orientation. Testing 5 patients with right hemisphere injury and 7 patients with left hemisphere injury confirmed each prediction. Additionally, errors in length estimation were exaggerated among patients with right hemisphere injury, most of whom had neglect. It is concluded that while crossover is accentuated in cases of neglect, it is not a consequence of neglect per se. As such, crossover bisections are not at odds with contemporary neglect theory. (JINS, 2002, 8, 107–114.)

scholarly journals Examining handedness and sex-related effects on line-bisection in childhood

2019 ◽  
Vol 12 (1) ◽  
pp. 111-119
Author(s):  
Ivanka V. Asenova ◽  
Yoanna R. Andonova-Tsvetanova
Keyword(s):  
Line Bisection ◽  
Group Level ◽  
Left Hand ◽  
Right Hand ◽  
Main Effect ◽  
On Line ◽  
True Center ◽  
The Right

Eighty-eight Bulgarian children (range 5 – 7 years old), 40 left handers (18 boys) and 48 right handers (26 boys), completed line-bisection test one time with each hand. In accordance with previous studies the results show that the majority of children demonstrated deviation to the left of the true center with the left hand and to the right with the right hand, suggesting symmetrical neglect. Sex, handedness and their interaction had no main effect on mean percentage deviation scores at the group level, but only sex had a significant impact on the frequency of symmetrical neglect (p < .05), with higher one in girls than in boys.

Influence of Colour Lightness Differences in Patients With Left Unilateral Spatial Neglect

2010 ◽  
Vol 16 (1) ◽  
pp. 1-13 ◽  
Author(s):  
Shinsuke Sato ◽  
Akio Tsubahara ◽  
Yoichiro Aoyagi ◽  
Takashi Hiraoka ◽  
Sumire Hasegawa ◽  
...  
Keyword(s):  
Japanese Version ◽  
Line Bisection ◽  
Spatial Neglect ◽  
Unilateral Spatial Neglect ◽  
Laterality Index ◽  
Green Background

AbstractWe used desk-based tasks to evaluate and clarify the effects of colour lightness differences (Liebmann effect) in patients with left unilateral spatial neglect (USN) following stroke. Participants were 30 adults with USN (16 men and 14 women; mean age = 72.3 years, SD = 8.9 years). They took the ‘Letter Cancellation Test’ of the Japanese version of the Behavioral Inattention Test using two types of paper: black letters with a yellow background (‘black on yellow’) and red letters with a green background (‘red on green’). They also took the Line Bisection Test and their laterality index (LI) was also determined. Paired t-tests were computed comparing the LI by colour displays. LI was higher for ‘black on yellow’ than for ‘red on green’ in patients with mild left USN. However, LI for ‘red on green’ was higher in patients with severe left USN. Colour lightness differences are likely on the left side in patients with relatively mild left USN, but not in those with severe left USN.

Stability of On-Line Bin Packing with Random Arrivals and Long-Run-Average Constraints

1990 ◽  
Vol 4 (4) ◽  
pp. 447-460 ◽  
Author(s):  
Coastas Courcobetis ◽  
Richard Weber
Keyword(s):  
Bin Packing ◽  
Random Processes ◽  
Sufficient Condition ◽  
Necessary And Sufficient Condition ◽  
Expected Number ◽  
Long Run ◽  
Different Types ◽  
On Line ◽  
Necessary And Sufficient ◽  
Uniformly Bounded

Items of various types arrive at a bin-packing facility according to random processes and are to be combined with other readily available items of different types and packed into bins using one of a number of possible packings. One might think of a manufacturing context in which randomly arriving subassemblies are to be combined with subassemblies from an existing inventory to assemble a variety of finished products. Packing must be done on-line; that is, as each item arrives, it must be allocated to a bin whose configuration of packing is fixed. Moreover, it is required that the packing be managed in such a way that the readily available items are consumed at predescribed rates, corresponding perhaps to optimal rates for manufacturing these items. At any moment, some number of bins will be partially full. In practice, it is important that the packing be managed so that the expected number of partially full bins remains uniformly bounded in time. We present a necessary and sufficient condition for this goal to be realized and describe an algorithm to achieve it.

scholarly journals Line Bisection in Visuo-Spatial Neglect: Disproof of a Conjecture

Cortex ◽  
1989 ◽  
Vol 25 (3) ◽  
pp. 517-521 ◽  
Author(s):  
Peter W. Halligan ◽  
John C. Marshall
Keyword(s):  
Line Bisection ◽  
Spatial Neglect

Recovery and regression in visuo-spatial neglect: A case study of learning in line bisection

Brain Injury ◽  
1991 ◽  
Vol 5 (1) ◽  
pp. 23-31 ◽  
Author(s):  
Peter W. Halligan ◽  
John C. Marshall
Keyword(s):  
Line Bisection ◽  
Spatial Neglect

Adaptive-passive structural vibration attenuation using distributed absorbers

2002 ◽  
Vol 216 (3) ◽  
pp. 223-235 ◽  
Author(s):  
N Jalili ◽  
E Esmailzadeh
Keyword(s):  
Vibration Suppression ◽  
Sufficient Conditions ◽  
Structural Vibration ◽  
Dynamic Vibration Absorber ◽  
Vibration Attenuation ◽  
Adaptive Capability ◽  
On Line ◽  
Lumped Masses ◽  
Necessary And Sufficient ◽  
Tuning Strategy

A distributed dynamic vibration absorber with adaptive capability is presented to improve vibration suppression characteristics of harmonically excited structures. A double-ended cantilever beam carrying intermediate lumped masses forms the absorber subsection. The adaptive capability is achieved through concurrent adjustment of the positions of the moving masses, along the beam, to comply with the desired optimal performance. The necessary and sufficient conditions for the existence of periodic oscillatory behaviour, along with some physical bounds placed on the absorber parameters, form a constrained optimization problem for the optimum tuning strategy. Through numerical simulations it is shown that adaptive tuning is achieved by the variation of tuning mass locations such that the first-mode natural frequency is modulated on-line. The optimally tuned absorber provides considerable vibration suppression improvement over the passive and detuned absorbers.

scholarly journals Emotion and space: lateralized emotional word detection depends on line bisection bias

Neuroscience ◽  
2009 ◽  
Vol 162 (4) ◽  
pp. 1101-1105 ◽  
Author(s):  
C. Tamagni ◽  
T. Mantei ◽  
P. Brugger
Keyword(s):  
Line Bisection ◽  
Emotional Word ◽  
Word Detection ◽  
On Line

scholarly journals Alzheimer's patients do not show left unilateral spatial neglect but exhibit peripheral inattention and simplification

2007 ◽  
Vol 1 (4) ◽  
pp. 374-380 ◽  
Author(s):  
Mari Kasai ◽  
Junichi Ishizaki ◽  
Kenichi Meguro
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Line Bisection ◽  
Spatial Neglect ◽  
Test Results ◽  
Unilateral Spatial Neglect ◽  
Complex Figure ◽  
Figure Test ◽  
Category Score

Abstract The Rey-Osterrieth Complex Figure Test (RCFT) is widely used to measure visuoperceptual and visuoconstructional skills, while the Line Bisection (LB) test is commonly employed to assess unilateral spatial neglect (USN). Previous studies have suggested that Alzheimer's disease (AD) patients may suffer from left USN. Objectives: The purpose of this study was to clarify whether left USN occurs in AD. Methods: Forty controls, 40 very mild AD patients and 31 mild/moderate AD patients performed both the RCFT copying and the LB test. Results: The very mild AD and mild/moderate AD groups had lower total RCFT copying scores and also scored lower in the "left" and "detail" categories compared to controls. However, there were no correlations between the left-category score for RCFT and the LB score. Instead, peripheral inattention and simplification patterns were noted. Conclusions: We found that the RCFT copying test is effective for detecting early AD and suggest that AD patients manifest peripheral inattention and simplification but not left USN.

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