The role of right side objects in left side neglect: A dissociation between perceptual and directional motor neglect

Làdavas, Elisabetta; Umiltà, Carlo; Ziani, Paola; Brogi, Alessandra; Minarini, Martina

doi:10.1016/0028-3932(93)90127-l

Cited by 56 publications

(22 citation statements)

References 30 publications

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“…Mesulam [23,24] proposed that premotor neglect might be correlated with anterior lesions, whereas more posterior lesions might cause perceptual neglect. This dichotomy has generally been supported in a range of studies [4,6,7,8,9,18,35]. Other studies, however, have produced more ambiguous results [1,14] or even contrary findings [6,21].…”

Section: Introductionmentioning

confidence: 88%

Categorisation of ‘perceptual’ and ‘premotor’ neglect patients across different tasks: is there strong evidence for a dichotomy?

et al. 2002

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The aim of the presented studies was to investigate whether classifications of neglect patients into perceptual (i.e. identifying a patient as suffering from mainly attentional/space representation deficits) and premotor (judging the main impairment to be related towards actions into contralesional space) categories is consistent across different line bisection assessment techniques that have, in the past, been designed to tease these potentially overlapping aspects of hemispatial neglect apart.Twelve patients with hemispatial neglect and three control groups were tested with the Overhead Task, adapted from Nico [Neuropsychologia 34 (1996) 471] in which patients were asked to bisect lines that were mirror reversed, the Pulley Device Technique, adapted from Bisiach et al. [Neurology 40 (1990) 1278] in which they had to perform a movement opposite to the direction of the transaction mark that bisected the line and the Landmark Test, adapted from Milner et al. [Neuropsychologia 30 (1992) 515] in which they had to manually point to the half of a centrally pre-bisected line that, to them, appeared shorter. The specific question was whether these three tasks would categorise the same set of patients in the same way?Most patients could be classified into either the premotor or perceptual category in each task, but no consistent categorisation emerged across the three techniques. Just 1 out of the 12 patients, was consistently classified across all three tasks. It seemed that despite the fact that all tasks essentially required a line bisection response, the perceptual and motor differences between the tasks were still great enough to result in inconsistent classifications. The Landmark Task classified the majority of patients into the perceptual neglect category, while the Overhead and Pulley Device Techniques tended to identify more patients as suffering from a premotor deficit (albeit not the same set of patients).

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Section: Introductionmentioning

confidence: 88%

Categorisation of ‘perceptual’ and ‘premotor’ neglect patients across different tasks: is there strong evidence for a dichotomy?

et al. 2002

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“…The use of this hand may have activated a right space representation, thus cancelling a weaker effect due to the passive left hand movement (for a further discussion of this point see the Discussion). For this reason in the present experiment an object naming task was used (for a similar procedure see Làdavas et al 1993). …”

Section: "Responding Effector"mentioning

confidence: 99%

Neglect as a deficit determined by an imbalance between multiple spatial representations

et al. 1997

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A previous study on neglect suggested that at least two hand parameters are crucial in producing an amelioration of neglect: the hand (left or right) and the spatial position of the hand (left or right). The improvement observed in perceiving left targets when the left hand acts in the left space can be due either to proprioceptive or to visual cuing. The stimulated left hand located in the left space may act as a powerful visual cue for the enhancement of the left visuo-spatial representation, in the same way as any other visual stimulus presented in the periphery of the visual field. Alternatively, it may be that the perceived hand location (due to the activation of the proprioceptive system) acts as an attentional field able to enhance the representation of the left space. In order to disentangle these two hypotheses, in the present study a naming task was executed by a group of neglect patients and by a control group. The subjects had to name all the objects depicted on a sheet of paper which were reflected on a mirror that inverted right and left space. While doing the naming performance, the subjects passively moved either the right or the left hand, in the left or right space. Stimuli and hand were reflected in the mirror that inverted right and left space and direct view of the stimuli and of the stimulated hand was prevented by a board. The results show that patients were more accurate at naming stimuli reflected in the left side of the mirror when the left hand was located and moved on the left side. In this condition, however, the left hand was seen in the right side of the mirror. It is therefore clear that the better performance was not due to visuo-spatial cuing but to a proprioceptive cuing effect. The results are discussed in terms of the relevance of personal and peripersonal spatial activation in the modulation of extrapersonal visual neglect. The coactivation of different spatial representations seems to be very influential on stimulus coding, thus confirming that spatial awareness is strictly related to the joint activity of multiple brain maps.

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“…Damage to the frontal, as well as the parietal, lobe was identified in six of the RBD+ patients which raises queries as to whether such repetitions are perseverations resulting from frontal lesions, rather than being directly associated with the neglect. Although this issue is rather complex, as evidence exists to connect frontal lesions with directional motor neglect (Lhdavas, Umilta, Ziani, Brogi & Minarini, 1993), further MannWhitney analyses of our data set indicated that total frequency of repetitions was not significantly associated with frontal lesions in either of the RBD groups (RBD+ with frontal lesion vs. RBD+ without frontal lesion: U = 8,Z = -0.85, p = .39; RBD-with frontal lesion vs. RBDwithout frontal lesion: U = 7, Z = -0.80, p = .42). Likewise, there were no significant differences in repetition frequency within any of the individual segments.…”

Section: Discussionmentioning

confidence: 99%

Directional Hyperattention in Tactile Neglect within Grasping Space

Haeske-Dewick

Canavan

Hömberg

1996

Journal of Clinical and Experimental Neuropsychology

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This study was motivated by the fact that unilateral neglect, an impediment to progress in patient rehabilitation, is often reported to occur in a wider area of space than that usually assessed in clinical settings. Neglect within "grasping space" (Halligan & Marshall, 1991; Kolb & Whishaw, 1990) was assessed via two search tasks: one in which search was guided by visual information and the other in which search was guided by tactile information. The performance of 10 left brain-damaged patients (LBD) and 20 right brain-damaged patients, 10 of whom showed left visual neglect (RBD+) while 10 did not (RBD-), was compared with that of age-matched controls. The visual search task confirmed the clinical diagnoses of unilateral visual neglect. On the tactile test, both RBD groups showed reduced search within the left hemispace, although this was a particularly strong feature of the performance of the RBD+ patients. Furthermore, this reduced leftwards exploration in RBD+ patients was associated with an increased frequency of repetitions made within the right hemispace, as had also been noted in some of these patients on conventional visual star cancellation. Results are discussed in relation to hyperattentional theories of directional spatial neglect.

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The role of right side objects in left side neglect: A dissociation between perceptual and directional motor neglect

Cited by 56 publications

References 30 publications

Categorisation of ‘perceptual’ and ‘premotor’ neglect patients across different tasks: is there strong evidence for a dichotomy?

Categorisation of ‘perceptual’ and ‘premotor’ neglect patients across different tasks: is there strong evidence for a dichotomy?

Neglect as a deficit determined by an imbalance between multiple spatial representations

Directional Hyperattention in Tactile Neglect within Grasping Space

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