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 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.

Case Report: Recovery and Reorganization after Congenital Unilateral Brain Damage

1984 ◽  
Vol 59 (3) ◽  
pp. 867-874 ◽  
Author(s):  
Ruth Nass
Keyword(s):  
Case Report ◽  
Brain Injury ◽  
Left Hemisphere ◽  
Dichotic Listening ◽  
Right Hemisphere ◽  
Matched Pair ◽  
Unilateral Brain Damage ◽  
Left And Right ◽  
Unilateral Injury ◽  
Unilateral Brain

Recovery and neural reorganization after congenital left- and right-brain injury is assessed on dichotic listening and tachistoscopic visuo-perceptual tasks. A matched-pair approach for age and type of lesion is used. Over-all, deficits are less pronounced than in adults. Innate specialization of both left and right hemispheres is supported by the data. In addition, a left-right maturational gradient is suggested by the all-around better performance of the child with left-hemisphere pathology. The later maturing, relatively less-committed right hemisphere is better able to compensate after unilateral injury.

scholarly journals The End of the Line for a Brain-Damaged Model of Unilateral Neglect

1997 ◽  
Vol 9 (2) ◽  
pp. 171-190 ◽  
Author(s):  
Michael C. Mozer ◽  
Peter W. Halligan ◽  
John C. Marshall
Keyword(s):  
Right Hemisphere ◽  
Orientation Angle ◽  
Line Length ◽  
The Body ◽  
Line Bisection ◽  
Simple Task ◽  
Unilateral Neglect ◽  
Related Disorder ◽  
On Line ◽  
The Right

For more than a century, it has been known that damage to the right hemisphere of the brain can cause patients to be unaware of the contralesional side of space. This condition, known as unilateral neglect, represents a collection of clinically related spatial disorders characterized by the failure in free vision to respond, explore, or orient to stimuli predominantly located on the side of space opposite the damaged hemisphere. Recent studies using the simple task of line bisection, a conventional diagnostic test, have proven surprisingly revealing with respect to the spatial and attentional impairments involved in neglect. In line bisection, the patient is asked to mark the midpoint of a thin horizontal lie on a sheet of paper. Neglect patients generally transect far to the right of the center. Extensive studies of line bisection have been conducted, manipulating-among other factors-line length, orientation, and position. We have simulated the pattern of results using an existing computational model of visual perception and selective attention called MORSEL (Mozer, 1991). MORSEL has already been used to model data in a related disorder, neglect dyslexia (Mozer & Behrmann, 1990). In this earlier work, MORSEL was “lesioned” in accordance with the damage we suppose to have occurred in the brains of neglect patients. The same model and lesion can simulate the detailed pattern of performance on line bisection, including the following observations: (1) no consistent across-subject bias is found in normals; (2) transection displacements are proportional to line length in neglect patients; (3) variability of displacements is proportional to line length, in both normals and patients; (4) position of the lines with respect to the body or the page on which they are drawn has little effect; and (5) for lines drawn at different orientations, displacements are proportional to the cosine of the orientation angle. MORSEL fails to account for one observation: across patients, the variability of displacements for a particular line length is roughly proportional to mean displacement. Nonetheless, the overall fit of the model is sufficiently good that we believe MORSEL can be used as a diagnostic tool to characterize the specific nature of a patient's deficit, and thereby has potential down the line in therapy.

scholarly journals Unilateral traumatic brain injury of the left and right hemisphere produces the left hindlimb response in rats

2021 ◽  
Author(s):  
Georgy Bakalkin ◽  
Olga Nosova ◽  
Daniil Sarkisyan ◽  
Mathias Hallberg ◽  
Mengliang Zhang ◽  
...  
Keyword(s):  
Traumatic Brain Injury ◽  
Spinal Cord ◽  
Brain Injury ◽  
Right Hemisphere ◽  
The Body ◽  
Injured Brain ◽  
Left Limb ◽  
Ketamine Anesthesia ◽  
Left And Right ◽  
Limb Flexion

AbstractTraumatic brain injury and stroke result in hemiplegia, hemiparesis, and asymmetry in posture. The effects are mostly contralateral; however, ipsilesional deficits may also develop. We here examined whether ablation brain injury and controlled cortical impact (CCI), a rat model of clinical focal traumatic brain injury, both centered over the left or right sensorimotor cortex, induced hindlimb postural asymmetry (HL-PA) with contralesional or ipsilesional limb flexion. The contralesional hindlimb was flexed after left or right side ablation injury. In contrast, both the left and right CCI unexpectedly produced HL-PA with flexion on left side. The flexion persisted after complete spinal cord transection suggesting that CCI triggered neuroplastic processes in lumbar neural circuits enabling asymmetric muscle contraction. Left limb flexion was exhibited under pentobarbital anesthesia. However, under ketamine anesthesia, the body of the left and right CCI rats bent laterally in the coronal plane to the ipsilesional side suggesting that the left and right injury engaged mirror-symmetrical motor pathways. Thus, the effects of the left and right CCI on HL-PA were not mirror-symmetrical in contrast to those of the ablation brain injury, and to the left and right CCI produced body bending. Ipsilateral effects of the left CCI on HL-PA may be mediated by a lateralized motor pathway that is not affected by the left ablation injury. Alternatively, the left-side-specific neurohormonal mechanism that signals from injured brain to spinal cord may be activated by both the left and right CCI but not by ablation injury.

The Identification of Affective-Prosodic Stimuli by Left- and Right-Hemisphere-Damaged Subjects

1992 ◽  
Vol 35 (5) ◽  
pp. 963-970 ◽  
Author(s):  
Diana Van Lancker ◽  
John J. sidtis
Keyword(s):  
Cerebral Hemisphere ◽  
Right Hemisphere ◽  
Function Analysis ◽  
Control Group ◽  
Acoustic Cues ◽  
Right Hemisphere Damage ◽  
Left And Right ◽  
Listening Task ◽  
Pattern Of Performance ◽  
Multiple Skills

Impairments in listening tasks that require subjects to match affective-prosodic speech utterances with appropriate facial expressions have been reported after both left- and right-hemisphere damage. In the present study, both left- and right-hemisphere-damaged patients were found to perform poorly compared to a nondamaged control group on a typical affective-prosodic listening task using four emotional types (happy, sad, angry, surprised). To determine if the two brain-damaged groups were exhibiting a similar pattern of performance with respect to their use of acoustic cues, the 16 stimulus utterances were analyzed acoustically, and the results were incorporated into an analysis of the errors made by the patients. A discriminant function analysis using acoustic cues alone indicated that fundamental frequency (FO) variability, mean FO, and syllable durations most successfully distinguished the four emotional sentence types. A similar analysis that incorporated the misclassifications made by the patients revealed that the left-hemisphere-damaged and right-hemisphere-damaged groups were utilizing these acoustic cues differently. The results of this and other studies suggest that rather than being lateralized to a single cerebral hemisphere in a fashion analogous to language, prosodic processes are made up of multiple skills and functions distributed across cerebral systems.

Differentiation Between Left and Right Hemisphere Forms of Intelligence

2006 ◽  
Author(s):  
Cristina Isaacs ◽  
Nichole McWhorter ◽  
Teri McHale ◽  
Lorrie N. Shiota ◽  
Henry V. Soper
Keyword(s):  
Right Hemisphere ◽  
Left And Right

scholarly journals No Evidence of Perceptual Pseudoneglect in Alexithymia

2021 ◽  
Vol 11 (3) ◽  
pp. 376
Author(s):  
Carmelo Mario Vicario ◽  
Gabriella Martino ◽  
Alex Marcuzzo ◽  
Giuseppe Craparo
Keyword(s):  
Right Hemisphere ◽  
Line Bisection ◽  
Mental Condition ◽  
Bisection Task ◽  
Rightward Shift ◽  
Behavioral Evidence ◽  
And Performance ◽  
The Right ◽  
Line Bisection Task ◽  
Tas 20

Neuroscience research links alexithymia, the difficulty in identifying and describing feelings and emotions, with left hemisphere dominance and/or right hemisphere deficit. To provide behavioral evidence for this neuroscientific hypothesis, we explored the relationship between alexithymia and performance in a line bisection task, a standard method for evaluating visuospatial processing in relation to right hemisphere functioning. We enrolled 222 healthy participants who completed a version of the 20-item Toronto Alexithymia Scale (TAS-20), which measures alexithymia, and were asked to mark (bisect) the center of a 10-cm horizontal segment. The results document a significant rightward shift in the center of the line in participants with borderline and manifest alexithymia compared with non-alexithymic individuals. The higher the TAS-20 score, the greater the rightward shift in the line bisection task. This finding supports the right hemisphere deficit hypothesis in alexithymia and suggests that visuospatial abnormalities may be an important component of this mental condition.

Patterns of Cognitive Test Performance As Functions of the Lateral Localization of Cerebral Abnormalities in the Temporal Lobe

1957 ◽  
Vol 103 (433) ◽  
pp. 758-772 ◽  
Author(s):  
Victor Meyer ◽  
H. Gwynne Jones
Keyword(s):  
Test Performance ◽  
Right Hemisphere ◽  
Cognitive Test ◽  
Temporal Relationships ◽  
Verbal Tasks ◽  
Specific Locus ◽  
Left And Right ◽  
Spatio Temporal ◽  
Cognitive Test Performance ◽  
Lateral Localization

Various investigations into the effects of brain injury on psychological test performance (Weisenburg and McBride, 1935; Patterson and Zangwill, 1944; Anderson, 1951; McFie and Piercy, 1952; Bauer and Becka, 1954; Milner, 1954) suggest the overall conclusion that patients with left hemisphere lesions are relatively poor at verbal tasks, while those with right-sided lesions do worst at practical tasks, particularly the manipulation of spatial or spatio-temporal relationships. Heilbfun's (1956) study confirmed that verbal deficits result from left-sided lesions but his left and right hemisphere groups produced almost identical scores on spatial tests. In so far as these workers paid attention to the specific sites of the lesions, their findings indicate that the pattern of test performance is a function of the hemisphere in which the lesion occurs rather than of its specific locus.

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