Signs Of Spatial Neglect Research Articles

Signs of spatial neglect in unilateral peripheral vestibulopathy.

In this study, the question of whether egocentric representation of space is impaired in chronic unilateral vestibulopathies was examined. The objective was to test current theories attributing a predominant role to vestibular afferents in spatial cognition and to assess whether representational neglect signs are common in peripheral vestibular loss. The subjective straight-ahead (SSA) direction was investigated using a horizontal rod allowing the translation and rotation components of the body midline representation to be dissociated in 21 patients with unilateral vestibular loss (right, 13; left, eight) and in 12 healthy controls. Compared to the controls, the patients with unilateral vestibulopathy showed a translation bias of their SSA, without rotation bias. The translation bias was not lateralized towards the lesioned side as typically found for biases reported after unilateral vestibular loss. Rather, the SSA bias was rightward whatever the side of the vestibular loss. The translation bias correlated with the vestibular loss, as measured by caloric response and vestibulo-ocular reflex gain, but not with the subjective visual vertical or the residual spontaneous nystagmus. The present data suggest that the dysfunctions of neural networks involved in egocentred and allocentred representations of space are differentially compensated for in unilateral vestibular defective patients. In particular, they suggest that asymmetrical vestibular inputs to cortical regions lead to representational spatial disturbances as does defective cortical processing of vestibular inputs in spatial neglect after right hemisphere stroke. They also highlight the predominant role of symmetrical and unaltered vestibular inputs in spatial cognition.

Conventional and functional assessment of spatial neglect: Clinical practice suggestions.

Spatial neglect (SN) constitutes a substantial barrier to functional recovery after acquired brain injury. However, because of its multimodal nature, no single test can capture all the signs of SN. To provide a clinically feasible solution, we used conventional neuropsychological tests as well as the Catherine Bergego Scale (CBS) via the Kessler Foundation Neglect Assessment Process (KF-NAP). The goal was to add evidence that a global approach should detect better even subtle signs of SN. Fourteen individuals with lesions located in the right cerebral hemisphere participated in the study. Participants were assessed with a comprehensive battery of neuropsychological tests, comprising a set of visuospatial tests to evaluate several spatial domains. In addition, patients underwent functional assessment with the Barthel Index, the Functional Independence Measure (FIM), and the CBS via KF-NAP. The CBS via KF-NAP was associated with the visuospatial paper-based tests (p = .004) as well as the Motor FIM (p = .003), and was more sensitive than the Behavioral Inattention Test-Conventional in detecting SN (p = .014). We showed that the CBS via KF-NAP was able: (a) to detect functional impairment, especially motor, related to SN; (b) to selectively measures spatial rather than nonspatial dysfunctions; and (c) to be highly sensitive in detecting SN signs especially in those patients with mild severity, covering several aspects of SN manifestations. The patient's SN diagnosis based on the CBS via KF-NAP is clinically important and directly relevant to care planning and goal setting. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Interpreting spatial dysgraphia after stroke: Straight ahead or straight above?

Spatial dysgraphia, frequently observed after a right hemisphere stroke, associates signs of spatial compression in relation to spatial neglect, and a tilted writing which remains to be explained. Here we present a case study suggesting that tilted writing is due to a tilted representation of the vertical. JW, a 75-year-old patient who underwent a right hemisphere hemorrhage showed a pusher syndrome and a writing tilted 11.1° upwardly, consistent through many tests, without other signs of spatial dysgraphia. We comprehensively assessed and followed most aspects of spatial cognition, until nine months post-stroke. For writing assessments, head and trunk were kept upright, and JW was instructed to write with the right (non-paretic) hand, on a paper sheet affixed onto a graphic tablet (to quantify writing orientation and time) positioned in front him on a slanted table (30°). The writing was tested with or without visual clues, and after a modulation of verticality perception. One month post-stroke, spatial neglect was severe with predominant signs of body neglect. Subjective straight-ahead was normal. Visual (VV) and postural (PV) perceptions of the vertical were tilted of 11°, counterclockwise. This transmodal tilt was similar both in direction and magnitude to the tilt found congruent on all features of writing: margin, lines, and letters. At 3 months the writing was found slower than a control subject when JW was instructed to write on blank paper (1.67 vs. 0.82 s/letter; P < 0.001), and faster when writing on lines inclined 24° upwardly (1.11 s/letter; P < 0.05). Then JW was himself tilted, in sitting for 10 min at 30° to right side, in the dark using the wheel paradigm. As expected this normalized PV for several min. This PV modulation significantly reduced the writing tilt, measured 20 min later (6.2°; P = 0.001) and increased the writing speed (0.89 s/letter; P = 0.002). Nine months post-stroke we found a dissociation between signs of spatial neglect, which disappeared, and a tilt remaining both in verticality perception and writing (5° and 8.8°, respectively). After a right hemisphere stroke, a tilted writing is likely a sign of a tilted verticality representation.

The role of parieto-temporal connectivity in pure neglect dyslexia

The initial stages of reading are characterised by parallel and effortless access to letters constituting a word. Neglect dyslexia is an acquired reading disorder characterised by omission or substitution of the initial or the final letters of words. Rarely, the disorder appears in a'pure’ form that is, without other signs of spatial neglect. Neglect dyslexia is linked to damage involving the inferior parietal lobe and regions of the temporal lobe, but the precise anatomical basis of the pure form of the disorder is unknown. Here, we show that pure neglect dyslexia is associated with decreased structural connectivity between the inferior parietal and lateral temporal lobe. We examined patient DM, who following bilateral occipito-parietal damage presented left neglect dyslexia together with right visual field loss, but no signs of spatial neglect. DM's reading errors were affected by word length and were much more frequent for pseudowords than for existing words. Most errors were omissions or substitutions of the first or second letter, and the spatial distribution of errors was similar for stimuli presented left or right of fixation. The brain lesions of DM comprised the inferior and superior parietal lobule as well as the cuneus and precuneus of the left hemisphere, and the angular gyrus and lateral occipital cortex of the right hemisphere. Diffusion tensor imaging revealed bilateral decrease of fibre tracts connecting the inferior parietal lobule with the superior and middle temporal cortex. These findings suggest that parieto-temporal connections play a significant role for the deployment of attention within words during reading.

Effects of visuoauditive integration on motor system in speech perception: A TMS study

Unilateral spatial neglect frequently occurs after right-hemisphere stroke. It represents a major problem in the domain of public health, since it prevents patients from orienting or responding to left-sided stimuli. The exact anatomical location of lesions underlying the manifestation of this syndrome is currently debated (Bartolomeo, 2012). In the present study, we used a longitudinal approach in order to identify the lesional predictors of chronic neglect in longrange white matter bundles. We present a longitudinal study of 37 patients with right-hemisphere damage, tested at the acute/subacute phase and at more than 1 year after the stroke. 27 patients presented signs of spatial neglect in the acute/subacute phase. Each patient underwent a radiological assessment including a DTI sequence, (50 directions; bvalue of 1000 mm2/s). Voxelwise statistical analysis of the fractional anisotropy (FA) data was carried out using TBSS (Tract-Based Spatial Statistics, Smith, 2006). The longitudinal follow-up revealed that only 10 patients (27%) recovered from neglect at retest. In acute/subacute neglect, a lower FAwas found in the way of the right Superior Longitudinal fasciculus (SLF II and III) and of the corpus callosum. In the chronic phase, TBSS analysis showed the implication of the posterior portion of the corpus callosum (splenium) and of SLF II & III. The voxelwise correlation between a cancellation task (Bells test) and FA maps found a lower FA in the way of the anterior corpus callosum, local frontal and fronto-parietal white matter (SLF II and III), and in the thalamus. Our results confirm a key role of fronto-parietal disconnection in the emergence and chronic persistence of neglect (Thiebaut de Schotten et al., 2012). Moreover, we demonstrated an implication of interhemispheric disconnection (splenium and forceps major) in chronic neglect. These findings support the hypothesis that interhemispheric disconnection may deprive the right frontoparietal pathway of visual inputs, amputing the brain reconstruction of the left hemi-space (Tomaiuolo et al., 2010), and that chronic neglect at least in part results from the activity of an isolated left hemisphere (Bartolomeo et al., 2007).

Intraoperative cortical mapping of visuospatial functions in parietal low-grade tumors: changing perspectives of neurophysiological mapping

The aim of this study was to explore the feasibility of intraoperative visuospatial mapping with the same criteria currently used to define essential language areas. The authors compared surgical procedures in 2 patients with similar tumors (Grade II oligodendroglioma in the right parietal lobe) undergoing awake, image-assisted surgery for lesion removal with intraoperative neurophysiological monitoring. The line bisection task was used in both patients but with different criteria. In the first case, the authors respected any area, even within the tumor, where significant interference was found (a stimulation-induced error in 2 of 3 applications defined an essential area). In the second case, they removed 1 essential area located in the tumor and recorded an uneventful clinical response soon thereafter. They continued to monitor the patient without stimulation and stopped the resection when the patient was close to the criteria valid for defining spatial neglect. The signs of spatial neglect were present for 3 days postoperatively and then cleared spontaneously. Subtotal tumor removal was achieved in both cases. Evidence in the present study reveals that areas for visuospatial functions cannot be assessed with the same criteria used for language functions, since essential areas located in the tumor can be safely removed.

Perception of longitudinal body axis in patients with stroke: a pilot study

Background and aims: To investigate the hypothesis that patients with a hemisphere stroke may perceive their longitudinal body axis (LBA) rotated in the frontal plane. This error in an egocentric...

Spatial Anisotropy of Saccadic Latency in Normal Subjects and Brain-Damaged Patients

In the present study, reaction time of oblique and orthogonal saccades was investigated in normal subjects and in two groups of patients with right (RBD) and left (LBD) vascular cerebral lesions and no signs of spatial neglect. Clear altitudinal effects were present in each group of subjects: saccadic latencies were longer in the lower than in the upper part of the visual field for both orthogonal and oblique saccades. Asymmetry along the horizontal meridian was present only in case of right hemisphere damage. This supports the view that a lesion in the right hemisphere causes a greater deficit of visual-spatial processing than a left hemisphere lesion. A cerebral lesion in the right and/or left hemisphere produces a general slowing in the saccadic latency and a general reduction in the accuracy of saccades with respect to normal subjects performance. Further, it seems that making saccades in oblique direction reduces the general saccade efficiency.