Chapter 20 Optic ataxia and Bálint's syndrome: neuropsychological and neurophysiological prospects

Pisella, Laure; Ota, Hisaaki; Vighetto, Alain; Rossetti, Yves

doi:10.1016/s0072-9752(07)88020-1

Cited by 12 publications

(6 citation statements)

References 115 publications

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“…At least post-acutely, patients reach accurately to fixated targets, but accuracy declines dramatically with eccentricity (Blangero, Ota et al, 2010;Perenin & Vighetto, 1988). It has been argued that this extrafoveal dependence is so fundamental that the definition of optic ataxia should exclude reaching errors in central vision (Jackson et al, 2009;Pisella et al, 2007Pisella et al, , 2008Pisella et al, , 2009. Consistent with this, the area of maximum lesion overlap in optic ataxia lies close to the parieto-occipital junction (POJ) Karnath & Perenin, 2005), which, in healthy people, is differentially active during reaching to extrafoveal targets (Prado et al, 2005).…”

Section: Introductionmentioning

confidence: 94%

“…The classical consequence of damage to the dorsal stream of vision in humans is optic ataxia, a disorder of visually-guided action (McIntosh, 2010;Pisella, Ota, Vighetto, & Rossetti, 2008). Originally described amongst a cluster of symptoms following bilateral parietal lesions (Bálint, 1909), optic ataxia has been spotlighted in recent years, as central to understanding dorsal stream function (Goodale & Milner, 1992;Milner & Goodale, 2006;Pisella, Binkofski, Lasek, Toni, & Rossetti, 2006;Rossetti, Pisella, & Vighetto, 2003).…”

Section: Introductionmentioning

confidence: 99%

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Correlated deficits of perception and action in optic ataxia

et al. 2011

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a b s t r a c tOptic ataxia, following dorsal stream lesions, is characterised by impaired visuomotor guidance. Recent studies have found concurrent perceptual deficits, but it is unclear whether these are functionally related to the visuomotor symptoms. We studied the ability of a well-documented patient (IG) with bilateral optic ataxia to react to sudden target jumps by correcting ongoing reaches or by explicitly reporting the jump direction. IG showed deficient reach corrections, especially for target jumps to the visual periphery, and was similarly slow to discriminate the same jumps perceptually. Across six test conditions, in which the retinal locations of target jumps were varied, her perceptual slowing mirrored her reaching deficit precisely. These findings confirm perceptual impairments after dorsal stream lesions, and imply a shared functional basis with the classical visuomotor symptoms of optic ataxia. Additionally, we show that the online correction deficit is determined dually by the retinal location to which the reach must be diverted, and the location to which it is initially directed. We suggest that this deficit, and its perceptual counterpart, can be traced to a slowed contralesional orienting of attention in optic ataxia.

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Section: Introductionmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Correlated deficits of perception and action in optic ataxia

et al. 2011

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“…Drawing on previous studies (for review see Pisella et al, 2008), we developed a computerized test adopting touchscreen technology to assess manual reaching in the visual periphery and to record spatio-temporal performances. A laptop computer, implemented with a touch-screen, at a distance of 50 cm from the subject, was used.…”

Section: Case Reportmentioning

confidence: 99%

Brain networks in posterior cortical atrophy: A single case tractography study and literature review

Migliaccio

Agosta

Toba

et al. 2012

Cortex

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Posterior cortical atrophy (PCA) is rare neurodegenerative dementia, clinically characterized by a progressive decline in higher-visual object and space processing. After a brief review of the literature on the neuroimaging in PCA, here we present a study of the brain structural connectivity in a patient with PCA and progressive isolated visual and visuo-motor signs. Clinical and cognitive data were acquired in a 58-years-old patient (woman, right-handed, disease duration 18 months). Brain structural and diffusion tensor (DT) Magnetic Resonance Imaging (MRI) were obtained. A voxel-based morphometry (VBM) study was performed to explore the pattern of gray matter (GM) atrophy, and a fully automatic segmentation was assessed to obtain the hippocampal volumes. DT MRI-based tractography was used to assess the integrity of long-range white matter (WM) pathways in the patient and in six sex- and age-matched healthy subjects. This PCA patient had a clinical syndrome characterized by left visual neglect, optic ataxia, and left limb apraxia, as well as mild visuo-spatial episodic memory impairment. VBM study showed bilateral posterior GM atrophy with right predominance; DT MRI tractography demonstrated WM damage to the right hemisphere only, including the superior and inferior longitudinal fasciculi and the inferior fronto-occipital fasciculus, as compared to age-matched controls. The homologous left-hemisphere tracts were spared. No difference was found between left and right hippocampal volumes. These data suggest that selective visuo-spatial deficits typical of PCA might not result from cortical damage alone, but by a right-lateralized network-level dysfunction including WM damage along the major visual pathways.

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“…A lesion of the dorsal pathway may cause optic ataxia. A patient with optic ataxia shows a gross spatial inaccuracy in reaching toward individual objects in his visual field (10–12). In optic ataxia, patients with unilateral lesions show marked disorders when required to reach to an object presented in their contralesional/ataxic visual field (“field effect”), and also when using their contralesional/ataxic hand (“hand effect”).…”

Section: Introductionmentioning

confidence: 99%

Memory for Spatial Locations in a Patient with Near Space Neglect and Optic Ataxia: Involvement of the Occipitotemporal Stream

Chieffi

Messina

et al. 2017

Front. Neurol.

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Previous studies suggested that the occipitoparietal stream orients attention toward the near/lower space and is involved in immediate reaching, whereas the occipitotemporal stream orients attention toward the far/upper space and is involved in delayed reaching. In the present study, we investigated the role of the occipitotemporal stream in attention orienting and delayed reaching in a patient (GP) with bilateral damage to the occipitoparietal areas and optic ataxia. GP and healthy controls took part in three experiments. In the experiment 1, the participants bisected lines oriented along radial, vertical, and horizontal axes. GP bisected radial lines farther, and vertical lines more above, than the controls, consistent with an attentional bias toward the far/upper space and near/lower space neglect. The experiment 2 consisted of two tasks: (1) an immediate reaching task, in which GP reached target locations under visual control and (2) a delayed visual reaching task, in which GP and controls were asked to reach remembered target locations visually presented. We measured constant and variable distance and direction errors. In immediate reaching task, GP accurately reached target locations. In delayed reaching task, GP overshot remembered target locations, whereas the controls undershot them. Furthermore, variable errors were greater in GP than in the controls. In the experiment 3, GP and controls performed a delayed proprioceptive reaching task. Constant reaching errors did not differ between GP and the controls. However, variable direction errors were greater in GP than in the controls. We suggest that the occipitoparietal damage, and the relatively intact occipitotemporal region, produced in GP an attentional orienting bias toward the far/upper space (experiment 1). In turns, the attentional bias selectively shifted toward the far space remembered visual (experiment 2), but not proprioceptive (experiment 3), target locations. As a whole, these findings further support the hypothesis of an involvement of the occipitotemporal stream in delayed reaching. Furthermore, the observation that in both delayed reaching tasks the variable errors were greater in GP than in the controls suggested that in optic ataxia is present not only a visuo-but also a proprioceptivo-motor integration deficit.

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Chapter 20 Optic ataxia and Bálint's syndrome: neuropsychological and neurophysiological prospects

Cited by 12 publications

References 115 publications

Correlated deficits of perception and action in optic ataxia

Correlated deficits of perception and action in optic ataxia

Brain networks in posterior cortical atrophy: A single case tractography study and literature review

Memory for Spatial Locations in a Patient with Near Space Neglect and Optic Ataxia: Involvement of the Occipitotemporal Stream

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