Line bisection in simulated homonymous hemianopia

Mitra, Anish R; Abegg, Mathias; Viswanathan, Jayalakshmi; Barton, Jason J.S.

doi:10.1016/j.neuropsychologia.2010.02.023

Cited by 29 publications

(22 citation statements)

References 28 publications

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“…Measurements of line bisection errors using traditional paper-and-pencil tasks or more controlled forced-choice versions of these tasks provide an practical means for measuring deviations in length perception in patients with hemianopia, and they have provided a framework for assessing the roles of attentional focus, eccentric fixation and lesion location on the development and magnitude of the HLBE (Barton & Black, 1998; Kerkhoff & Schenk, 2011; Kuhn, et al, 2012; Mitra, et al, 2010; Schuett, et al, 2011; Zihl, et al, 2009). However, bisection tasks are generally not well suited for characterizing distortions in perception that occur across large portions of the visual field.…”

Section: Discussionmentioning

confidence: 99%

“…Though the HLBE is well documented, there are several unresolved issues that have inspired recent research in this area (Kerkhoff & Schenk, 2011; Kuhn, et al, 2012; Mitra, Abegg, Viswanathan, & Barton, 2010; Ogun, Viswanathan, & Barton, 2011; Schuett, Dauner, & Zihl, 2011; Zihl, Samann, Schenk, Schuett, & Dauner, 2009). Some studies have reported that the HLBE is found only in patients with lesions in extrastriate visual areas (Schuett, et al, 2011; Zihl, et al, 2009), although other research that simulated hemianopia in neurologically healthy participants suggests that the HLBE results from loss of vision within a large region of visual space, and does not only arise with hemianopia due to extrastriate lesions (Mitra, et al, 2010; Ogun, et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

“…Some studies have reported that the HLBE is found only in patients with lesions in extrastriate visual areas (Schuett, et al, 2011; Zihl, et al, 2009), although other research that simulated hemianopia in neurologically healthy participants suggests that the HLBE results from loss of vision within a large region of visual space, and does not only arise with hemianopia due to extrastriate lesions (Mitra, et al, 2010; Ogun, et al, 2011). Other work has investigated the development of a “pseudo-fovea” (i.e., eccentric fixation) in hemianopia, similar to those observed in patients with central field loss following macular degeneration (Cheung & Legge, 2005; Crossland, Culham, Kabanarou, & Rubin, 2005), and the role that shifts in spatial attention play in the HLBE (Kuhn, et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

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Spatial distortions in localization and midline estimation in hemianopia and normal vision

et al. 2015

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Studies have shown that individuals with hemianopia tend to bisect a line toward their blind, contralesional visual field, termed the hemianopic line bisection error (HLBE). One theory proposes that the HLBE is a perceptual distortion resulting from expansion of the central region of visual space. If true, perceptual expansions of the central regions in the intact hemifield should also be present and observable across different tasks. We tested this hypothesis using a peripheral localization task to assess localization and midpoint estimation along the horizontal axis of the visual field. In this task, participants judged the location of a target dot presented inside a Goldmann perimeter relative to their perceived visual field boundary. In Experiment 1, we tested neurologically healthy participants on the peripheral localization task as well as a novel midpoint assessment task in which participants reported their perceived midpoint along the horizontal axis of their left and right visual fields. The results revealed consistency in individual biases across the two tasks. We then used the peripheral localization task to test whether two patients with hemianopia showed a selective expansion of central visual space. For these patients, three axes were tested: the spared temporal horizontal axis and the upper and lower vertical axes. The results support the notion that the HLBE is due to expansion of perceived space along the spared temporal axis. Together, the results of both experiments validate the use of these novel paradigms for exploring perceptual asymmetries in both healthy individuals and patients with visual field loss.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Spatial distortions in localization and midline estimation in hemianopia and normal vision

et al. 2015

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“…This has also been demonstrated in healthy subjects (Mitra, Abegg, Viswanathan, & Barton, 2010; Ogun, Viswanathan, & Barton, 2011) when using an apparatus that mimicked a hemianopia such that when these normal subjects attempted to perform line bisections they deviated to the side of their hemianopia. These results suggest that the attentional bias associated with hemianopia may be compensatory rather than induced by brain injury.…”

Section: Introductionmentioning

confidence: 68%

The blindside: Impact of monocular occlusion on spatial attention

Burtis

Mishra

Heilman

2013

Journal of Clinical and Experimental Neuropsychology

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Monocular occlusion has been posited to reduce activation of the contralateral hemisphere (“Sprague effect”), thus inducing a contralateral spatial bias (toward the viewing eye). Healthy right-handed participants bisected horizontal lines during monocular eye viewing. Although subjects tended to deviate away from the viewing eye, only left eye viewing deviated significantly right of midline. These results suggest that eye patching may induce an attentional compensation similar to hemianopic patients. Alternatively, increased activation of higher cortical regions mediating spatial attention in contralateral hemispace may be an adaptive response to decreased activation of its ipsilateral superior colliculus induced by contralateral eye patching.

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“…Indeed, in hemianopia spatial distortion has been documented close to the borders of the scotoma. Such distortion would explain the occurrence of the so-called Hemianopic Line Bisection Error (HLBE), that is the bisection of lines biased toward the blind hemifield (see for example [2][3][4][5]), or an illusory shorter perception of lines crossing a scotoma of cortical origin [6].…”

Section: Introductionmentioning

confidence: 99%