Not Just Language: Persisting Lateralized Visuospatial Impairment after Left Hemisphere Stroke

2016 ◽  
Vol 22 (7) ◽  
pp. 695-704 ◽  
Author(s):  
Krista Schendel ◽  
Nina F. Dronkers ◽  
And U. Turken
Keyword(s):  
Visual Search ◽  
Visual Attention ◽  
Left Hemisphere ◽  
Search Task ◽  
Right Hemisphere ◽  
Visual Search Task ◽  
Viewing Time ◽  
Stroke Group ◽  
The Right ◽  
Left Hemisphere Stroke

AbstractObjectives: Imbalances in spatial attention are most often associated with right hemisphere brain injury. This report assessed 25 chronic left hemisphere stroke patients for attentional bias. Methods: Participants were evaluated with a computerized visual search task and a standardized neuropsychological assessment known as the Behavioral Inattention Test (BITC). Twenty age-matched controls were also tested. Results: Although little to no attentional impairment was observed on the BITC, the computerized visual search task revealed statistically significant contralesional attentional impairment in the left hemisphere stroke group. Specifically, these participants required 208 ms more viewing time, on average, to reliably detect visual targets on the right side of the display compared to detection on the left side, while controls showed a difference of only 8 ms between the two sides. Conclusions: The observation of significant leftward visuospatial bias in this chronic stroke group provides further evidence that the left hemisphere also plays a role in the balance of visual attention across space. These results have implications for left hemisphere patients who are often not screened for visuospatial problems, as well as for theories of visual attention which have primarily emphasized the role of the right hemisphere. (JINS, 2016, 22, 695–704)

scholarly journals Regional Shape Abnormalities in Thalamus and Verbal Memory Impairment After Subcortical Infarction

2019 ◽  
Vol 33 (6) ◽  
pp. 476-485 ◽  
Author(s):  
Gang Liu ◽  
Xiaoqing Tan ◽  
Chao Dang ◽  
Shuangquan Tan ◽  
Shihui Xing ◽  
...  
Keyword(s):  
Left Hemisphere ◽  
Verbal Memory ◽  
Memory Impairment ◽  
Right Hemisphere ◽  
Brain Structures ◽  
Change Rate ◽  
Immediate Recall ◽  
Stroke Group ◽  
Left Hemisphere Stroke ◽  
Subcortical Infarction

Background. Subcortical infarcts can result in verbal memory impairment, but the potential underlying mechanisms remain unknown. Objective. We investigated the spatiotemporal deterioration patterns of brain structures in patients with subcortical infarction and identified the regions that contributed to verbal memory impairment. Methods. Cognitive assessment and structural magnetic resonance imaging were performed 1, 4, and 12 weeks after stroke onset in 28 left-hemisphere and 22 right-hemisphere stroke patients with subcortical infarction. Whole-brain volumetric analysis combined with a further-refined shape analysis was conducted to analyze longitudinal morphometric changes in brain structures and their relationship to verbal memory performance. Results. Between weeks 1 and 12, significant volume decreases in the ipsilesional basal ganglia, inferior white matter, and thalamus were found in the left-hemisphere stroke group. Among those 3 structures, only the change rate of the thalamus volume was significantly correlated with that in immediate recall. For the right-hemisphere stroke group, only the ipsilesional basal ganglia survived the week 1 to week 12 group comparison, but its change rate was not significantly correlated with the verbal memory change rate. Shape analysis of the thalamus revealed atrophies of the ipsilesional thalamic subregions connected to the prefrontal, temporal, and premotor cortices in the left-hemisphere stroke group and positive correlations between the rates of those atrophies and the change rate in immediate recall. Conclusions. Secondary damage to the thalamus, especially to the left subregions connected to specific cortices, may be associated with early verbal memory impairment following an acute subcortical infarct.

Grapheme–Color Synesthesia Influences Overt Visual Attention

2009 ◽  
Vol 21 (2) ◽  
pp. 246-258 ◽  
Author(s):  
Jonathan S. A. Carriere ◽  
Daniel Eaton ◽  
Michael G. Reynolds ◽  
Mike J. Dixon ◽  
Daniel Smilek
Keyword(s):  
Visual Search ◽  
Eye Movements ◽  
Visual Attention ◽  
Eye Tracking ◽  
Search Task ◽  
Visual Search Task ◽  
Free Viewing ◽  
Colored Target

For individuals with grapheme–color synesthesia, achromatic letters and digits elicit vivid perceptual experiences of color. We report two experiments that evaluate whether synesthesia influences overt visual attention. In these experiments, two grapheme–color synesthetes viewed colored letters while their eye movements were monitored. Letters were presented in colors that were either congruent or incongruent with the synesthetes' colors. Eye tracking analysis showed that synesthetes exhibited a color congruity bias—a propensity to fixate congruently colored letters more often and for longer durations than incongruently colored letters—in a naturalistic free-viewing task. In a more structured visual search task, this congruity bias caused synesthetes to rapidly fixate and identify congruently colored target letters, but led to problems in identifying incongruently colored target letters. The results are discussed in terms of their implications for perception in synesthesia.

Salience Representation in the Parietal and Frontal Cortex

2010 ◽  
Vol 22 (5) ◽  
pp. 918-930 ◽  
Author(s):  
Alexandre Zenon ◽  
Nabil Filali ◽  
Jean-René Duhamel ◽  
Etienne Olivier
Keyword(s):  
Visual Search ◽  
Search Task ◽  
Visual Search Task ◽  
Reporting Rate ◽  
Angular Gyrus ◽  
Dual Tasks ◽  
Visual Item ◽  
Two Factors ◽  
The Right ◽  
Salience Map

Some objects in the visual field are more likely to attract attention because they are either intrinsically eye catching or relevant in the context of a particular task. These two factors, known as stimulus-driven and goal-directed factors, respectively, are thought to be integrated into a unique salience map, possibly located in the frontal or the parietal cortex. However, the distinct contribution of these two regions to salience representation is difficult to establish experimentally and remains debated. In an attempt to address this issue, we designed several dual tasks composed of a letter reporting task and a visual search task, allowing us to quantify the salience of each visual item by measuring its probability to be selected by attention. In Experiment 1, the salience of the visual search items depended on a combination of conspicuity and relevance factors, whereas in Experiment 2, stimulus-driven and goal-directed factors were tested separately. Then, we used transcranial magnetic stimulation to interfere transiently with the function of the right angular gyrus (ANG) or right FEFs in healthy subjects performing these dual tasks. We found that interfering with the ANG and the FEF function specifically altered the influence of salience on the letter report rate without affecting the overall letter reporting rate, suggesting that these areas are involved in salience representation. In particular, the present study suggests that ANG is involved in goal-directed salience representation, whereas FEF would rather house a global salience map integrating both goal-directed and stimulus-driven factors.

scholarly journals Processing of metaphors in transcortical motor aphasia

2008 ◽  
Vol 2 (4) ◽  
pp. 339-348 ◽  
Author(s):  
Renata Mancopes ◽  
Fernanda Schultz
Keyword(s):  
Left Hemisphere ◽  
Right Hemisphere ◽  
Great Emphasis ◽  
Clinical Aspects ◽  
Metaphor Comprehension ◽  
Motor Aphasia ◽  
The Right ◽  
Left Hemisphere Stroke ◽  
Comprehension Tests ◽  
The Brain

Abstract Great emphasis has been placed on the right hemisphere, due to its possible selective contribution, in the processing of metaphorical statements. Objectives: To describe the processing of metaphors in the case of a patient with transcortical motor aphasia, using specific tests for patients with encephalic injuries of the right hemisphere, and to contribute to the discussion on the inter-hemispheric relationships associated with this function. Methods: A 54 year-old man with transcortical motor aphasia was evaluated three years after a left hemisphere stroke. The tasks of comprehension of metaphors were based on the subtest Metaphor Comprehension Task of the Montreal Evaluation of Communications Scale (MEC). Two metaphor comprehension tests were applied, in 45-minute sessions with a 48 hour interval between each. Test 1 involved comprehension of the metaphors according to the options offered, and Test 2 the comprehension of metaphors measured by response time and visual field. Results: Although the right hemisphere was not affected by the stroke in this case, difficulties were observed in the processing of metaphors. Conclusions: This study suggests that the left hemisphere participates in the processing of figurative meanings. The adaptability of the brain can also re-accommodate the uninjured areas of the brain, causing the dynamic of the brain to be modified. As a result, deducing cerebral functions based on clinical data can be problematic. The value of this study is that it can contribute to clinical aspects of language rehabilitation.

scholarly journals Visual Attention in The Fovea and The Periphery during Visual Search

2021 ◽  
Author(s):  
Jie Zhang ◽  
Xiaocang Zhu ◽  
Shanshan Wang ◽  
Hossein Esteky ◽  
Yonghong Tian ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Visual Search ◽  
Visual Field ◽  
Visual Attention ◽  
Search Task ◽  
Visual Search Task ◽  
Common View ◽  
Serial Process ◽  
Feature Attention ◽  
Task Feature

Visual search depends on both the foveal and peripheral visual system, yet the foveal attention mechanisms is still lack of insights. We simultaneously recorded the foveal and peripheral activities in V4, IT and LPFC, while monkeys performed a category-based visual search task. Feature attention enhanced responses of Face-selective, House-selective, and Non-selective foveal cells in visual cortex. While foveal attention effects appeared no matter the peripheral attention effects, paying attention to the foveal stimulus dissipated the peripheral feature attentional effects, and delayed the peripheral spatial attentional effects. When target features appeared both in the foveal and the peripheral, feature attention effects seemed to occur predominately in the foveal, which might not distribute across the visual field according to common view of distributed feature attention effects. As a result, the parallel attentive process seemed to occur during distractor fixations, while the serial process predominated during target fixations in visual search.

scholarly journals Head Position of Patients with Right Hemisphere Damage during a Visual Search Task in a Large Field

2018 ◽  
Vol 08 (02) ◽  
pp. 190-202
Author(s):  
Ken Nakatani ◽  
Shusuke Takahashi ◽  
Daisuke Kimura ◽  
Masako Notoya ◽  
Nobuyuki Sunahara ◽  
...  
Keyword(s):  
Visual Search ◽  
Search Task ◽  
Right Hemisphere ◽  
Visual Search Task ◽  
Head Position ◽  
Large Field ◽  
Right Hemisphere Damage

scholarly journals Right Hemisphere Remapping of Naming Functions Depends on Lesion Size and Location in Poststroke Aphasia

2017 ◽  
Vol 2017 ◽  
pp. 1-17 ◽  
Author(s):  
Laura M. Skipper-Kallal ◽  
Elizabeth H. Lacey ◽  
Shihui Xing ◽  
Peter E. Turkeltaub
Keyword(s):  
Motor Cortex ◽  
Left Hemisphere ◽  
Neural Plasticity ◽  
Right Hemisphere ◽  
Inferior Frontal Gyrus ◽  
Lesion Size ◽  
Language Function ◽  
The Right ◽  
Left Hemisphere Stroke ◽  
Aphasia Recovery

The study of language network plasticity following left hemisphere stroke is foundational to the understanding of aphasia recovery and neural plasticity in general. Damage in different language nodes may influence whether local plasticity is possible and whether right hemisphere recruitment is beneficial. However, the relationships of both lesion size and location to patterns of remapping are poorly understood. In the context of a picture naming fMRI task, we tested whether lesion size and location relate to activity in surviving left hemisphere language nodes, as well as homotopic activity in the right hemisphere during covert name retrieval and overt name production. We found that lesion size was positively associated with greater right hemisphere activity during both phases of naming, a pattern that has frequently been suggested but has not previously been clearly demonstrated. During overt naming, lesions in the inferior frontal gyrus led to deactivation of contralateral frontal areas, while lesions in motor cortex led to increased right motor cortex activity. Furthermore, increased right motor activity related to better naming performance only when left motor cortex was lesioned, suggesting compensatory takeover of speech or language function by the homotopic node. These findings demonstrate that reorganization of language function, and the degree to which reorganization facilitates aphasia recovery, is dependent on the size and site of the lesion.

scholarly journals Unilateral Stroke: Computer-based Assessment Uncovers Non-Lateralized and Contralesional Visuoattentive Deficits

2021 ◽  
pp. 1-11
Author(s):  
Sanna Villarreal ◽  
Matti Linnavuo ◽  
Raimo Sepponen ◽  
Outi Vuori ◽  
Mario Bonato ◽  
...  
Keyword(s):  
Left Hemisphere ◽  
Right Hemisphere ◽  
Stroke Patients ◽  
Cancellation Task ◽  
Computer Based ◽  
Left And Right ◽  
The Right ◽  
Visual Inattention ◽  
Left Hemisphere Stroke ◽  
Right Hemisphere Stroke

Abstract Objective: Patients with unilateral stroke commonly show hemispatial neglect or milder contralesional visuoattentive deficits, but spatially non-lateralized visuoattentive deficits have also been reported. The aim of the present study was to compare spatially lateralized (i.e., contralesional) and non-lateralized (i.e., general) visuoattentive deficits in left and right hemisphere stroke patients. Method: Participants included 40 patients with chronic unilateral stroke in either the left hemisphere (LH group, n = 20) or the right hemisphere (RH group, n = 20) and 20 healthy controls. To assess the contralesional deficits, we used a traditional paper-and-pencil cancellation task (the Bells Test) and a Lateralized Targets Computer Task. To assess the non-lateralized deficits, we developed a novel large-screen (173 × 277 cm) computer method, the Ball Rain task, with moving visual stimuli and fast-paced requirements for selective attention. Results: There were no contralesional visuoattentive deficits according to the cancellation task. However, in the Lateralized Targets Computer Task, RH patients missed significantly more left-sided than right-sided targets in bilateral trials. This omission distribution differed significantly from those of the controls and LH patients. In the assessment of non-lateralized attention, RH and LH patients missed significantly more Ball Rain targets than controls in both the left and right hemifields. Conclusions: Computer-based assessment sensitively reveals various aspects of visuoattentive deficits in unilateral stroke. Patients with either right or left hemisphere stroke demonstrate non-lateralized visual inattention. In right hemisphere stroke, these symptoms can be accompanied by subtle contralesional visuoattentive deficits that have remained unnoticed in cancellation task.

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