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.

Stop and Go: The Neural Basis of Selective Movement Prevention

2009 ◽  
Vol 21 (6) ◽  
pp. 1193-1203 ◽  
Author(s):  
James P. Coxon ◽  
Cathy M. Stinear ◽  
Winston D. Byblow
Keyword(s):  
Motor Cortex ◽  
Right Hemisphere ◽  
Inferior Frontal Gyrus ◽  
Middle Finger ◽  
Neural Basis ◽  
Movement Initiation ◽  
Stop And Go ◽  
Inferior Parietal Cortex ◽  
Supplementary Motor Cortex ◽  
The Right

Converging lines of evidence show that volitional movement prevention depends on the right prefrontal cortex (PFC), especially the right inferior frontal gyrus (IFG). Selective movement prevention refers to the rapid prevention of some, but not all, movement. It is unknown whether the IFG, or other prefrontal areas, are engaged when movement must be selectively prevented, and whether additional cortical areas are recruited. We used rapid event-related fMRI to investigate selective and nonselective movement prevention during performance of a temporally demanding anticipatory task. Most trials involved simultaneous index and middle finger extension. Randomly interspersed trials required the prevention of one, or both, finger movements. Regions of the right hemisphere, including the IFG, were active for selective and nonselective movement prevention, with an overlap in the inferior parietal cortex and the middle frontal gyrus. Selective movement prevention caused a significant delay in movement initiation of the other digit. These trials were associated with activation of the medial frontal cortex. The results provide support for a right-hemisphere network that temporarily “brakes” all movement preparation. When movement is selectively prevented, the supplementary motor cortex (SMA/pre-SMA) may participate in conflict resolution and subsequent reshaping of excitatory drive to the motor cortex.

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.

Ipsilateral Motor Cortex Activity During Unimanual Hand Movements Relates to Task Complexity

2005 ◽  
Vol 93 (3) ◽  
pp. 1209-1222 ◽  
Author(s):  
Timothy Verstynen ◽  
Jörn Diedrichsen ◽  
Neil Albert ◽  
Paul Aparicio ◽  
Richard B. Ivry
Keyword(s):  
Motor Cortex ◽  
Left Hemisphere ◽  
Time Course ◽  
Right Hemisphere ◽  
Task Complexity ◽  
Hand Movements ◽  
Left Hand ◽  
Sequential Structure ◽  
Single Finger ◽  
The Right

Functional imaging studies have revealed recruitment of ipsilateral motor areas during the production of sequential unimanual finger movements. This phenomenon is more prominent in the left hemisphere during left-hand movements than in the right hemisphere during right-hand movements. Here we investigate whether this lateralization pattern is related specifically to the sequential structure of the unimanual action or generalizes to other complex movements. Using event-related fMRI, we measured activation changes in the motor cortex during three types of unimanual movements: repetitions of a sequence of movements with multiple fingers, repetitive “chords” composed of three simultaneous key presses, and simple repetitive tapping movements with a single finger. During sequence and chord movements, strong ipsilateral activation was observed and was especially pronounced in the left hemisphere during left-hand movements. This pattern was evident for both right-handed and, to a lesser degree, left-handed individuals. Ipsilateral activation was less pronounced in the tapping condition. The site of ipsilateral activation was shifted laterally, ventrally, and anteriorly with respect to that observed during contralateral movements and the time course of activation implied a role in the execution rather than planning of the movement. A control experiment revealed that strong ipsilateral activity in left motor cortex is specific to complex movements and does not depend on the number of required muscles. These findings indicate a prominent role of left hemisphere in the execution of complex movements independent of the sequential nature of the task.

Evidence for Development of Distinction of Voice Onset Time in a Child with Left-Hemisphere Lesion

1995 ◽  
Vol 81 (3) ◽  
pp. 1001-1002
Author(s):  
Kelly Paulson-Sebold ◽  
Ludie R. Hansen ◽  
J. Anthony Seikel ◽  
Patricia M. Hargrove ◽  
Gail D. Chermak
Keyword(s):  
Left Hemisphere ◽  
Right Hemisphere ◽  
Voice Onset Time ◽  
Onset Time ◽  
Language Function ◽  
Partial Removal ◽  
Hemisphere Lesion ◽  
The Right

Following surgery for partial removal of the posterior left hemisphere at 5 mo., voice onset time was assessed to 9; 11 yr. Left-hemisphere language function associated with voicing appeared subsumed by the right hemisphere.

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 The Role Of Neuroplasticity Types In Aphasia Recovery And Its Influencing Factors: A Systematic Review Of Literature

2017 ◽  
pp. 76
Author(s):  
Alireza Aghaz
Keyword(s):  
Systematic Review ◽  
Influencing Factors ◽  
Left Hemisphere ◽  
Speech Therapy ◽  
Right Hemisphere ◽  
Pubmed Database ◽  
Surrounding Areas ◽  
The Right ◽  
Aphasia Recovery

Background and Objectives: Aphasia is common consequence of stroke. Most people with aphasia in the acute phase show some degree of spontaneous recovery, most of which occurs during the first two to three months. Neuro-linguistic mechanisms of recovery in aphasia remain a lot unknown still, but considerably depends to the amount of change plasticity in brain of patients after stroke. The aim of this article is review of the role of Neuroplasticity types in aphasia recovery and its influencing factors: a systematic review of literatureMethods: This study is a review of all articles listed in PubMed database from January 1990 to September, 2016 that were identified using the keywords Neuroplasticity and aphasia (in titles) and language.Results: Three types of changes in the activity of the nervous system after a stroke, is closely linked with aphasia recovery: 1. Reactivation of damaged areas of the left hemisphere or activities it`s surrounding in language tasks 2. Acquisition or manifest of the ability to process language in the nondominant right Hemisphere 3. The wrong activity of nondominant right hemisphere that can prevent language improvement.Discussion and Conclusion: Most of studies have shown involvement of surrounding areas in the left hemisphere lesion in language improvement, others reported employment of the right hemisphere regions and some others have known useful the involvement of both hemispheres in language improvement. It is difficult, aphasia improvement prediction due to the interaction of various factors. The most promising results aphasia treatment for the reorganization of the brain, caused by speech therapy that lead to quick improvements considerably. 

scholarly journals The Role of the Right Hemisphere White Matter Tracts in Chronic Aphasic Patients After Damage of the Language Tracts in the Left Hemisphere

2021 ◽  
Vol 15 ◽  
Author(s):  
Evie Kourtidou ◽  
Dimitrios Kasselimis ◽  
Georgia Angelopoulou ◽  
Efstratios Karavasilis ◽  
Georgios Velonakis ◽  
...  
Keyword(s):  
White Matter ◽  
Left Hemisphere ◽  
Right Hemisphere ◽  
Diffusion Tensor ◽  
Inferior Frontal Gyrus ◽  
Language Performance ◽  
White Matter Tracts ◽  
Post Stroke ◽  
Language Functions ◽  
The Right

The involvement of the right hemisphere (RH) in language, and especially after aphasia resulting from left hemisphere (LH) lesions, has been recently highlighted. The present study investigates white matter structure in the right hemisphere of 25 chronic post-stroke aphasic patients after LH lesions in comparison with 24 healthy controls, focusing on the four cortico-cortical tracts that link posterior parietal and temporal language-related areas with Broca’s region in the inferior frontal gyrus of the LH: the Superior Longitudinal Fasciculi II and III (SLF II and SLF III), the Arcuate Fasciculus (AF), and the Temporo-Frontal extreme capsule Fasciculus (TFexcF). Additionally, the relationship of these RH white matter tracts to language performance was examined. The patients with post-stroke aphasia in the chronic phase and the healthy control participants underwent diffusion tensor imaging (DTI) examination. The aphasic patients were assessed with standard aphasia tests. The results demonstrated increased axial diffusivity in the RH tracts of the aphasic patients. Patients were then divided according to the extent of the left hemisphere white matter loss. Correlations of language performance with radial diffusivity (RD) in the right hemisphere homologs of the tracts examined were demonstrated for the TFexcF, SLF III, and AF in the subgroup with limited damage to the LH language networks and only with the TFexcF in the subgroup with extensive damage. The results argue in favor of compensatory roles of the right hemisphere tracts in language functions when the LH networks are disrupted.

scholarly journals The Role Of Neuroplasticity Types In Aphasia Recovery And Its Influencing Factors: A Systematic Review Of Literature

2017 ◽  
pp. 42
Author(s):  
Alireza Aghaz
Keyword(s):  
Systematic Review ◽  
Influencing Factors ◽  
Left Hemisphere ◽  
Speech Therapy ◽  
Right Hemisphere ◽  
Pubmed Database ◽  
Surrounding Areas ◽  
The Right ◽  
Aphasia Recovery

Background and Objectives: aphasia is common consequence of stroke. Most people with aphasia in the acute phase show some degree of spontaneous recovery, most of which occurs during the first two to three months. Neuro-linguistic mechanisms of recovery in aphasia remain a lot unknown still, but considerably depends to the amount of change plasticity in brain of patients after stroke. The aim of this article is review of the role of Neuroplasticity types in aphasia recovery and its influencing factors: a systematic review of literatureMethods: this study is a review of all articles listed in PubMed database from January 1990 to September, 2016 that were identified using the keywords Neuroplasticity and aphasia (in titles) and language.Results: Three types of changes in the activity of the nervous system after a stroke, is closely linked with aphasia recovery: 1. Reactivation of damaged areas of the left hemisphere or activities it`s surrounding in language tasks 2. Acquisition or manifest of the ability to process language in the nondominant right Hemisphere 3. The wrong activity of nondominant right hemisphere that can prevent language improvement.Discussion and Conclusion: Most of studies have shown involvement of surrounding areas in the left hemisphere lesion in language improvement, others reported employment of the right hemisphere regions and some others have known useful the involvement of both hemispheres in language improvement. It is difficult, aphasia improvement prediction due to the interaction of various factors. The most promising results aphasia treatment for the reorganization of the brain, caused by speech therapy that lead to quick improvements considerably.  

scholarly journals Right-hemisphere compensation during word production: A single case of left-hemisphere young stroke

2021 ◽  
Author(s):  
Irina Chupina ◽  
Joanna Sierpowska ◽  
Xiaochen Zheng ◽  
Anna Dewenter ◽  
Maria Carla Piastra ◽  
...  
Keyword(s):  
Left Hemisphere ◽  
Structural Damage ◽  
Right Hemisphere ◽  
Single Case ◽  
Inferior Frontal Gyrus ◽  
Age Groups ◽  
Word Finding ◽  
Deterministic Tractography ◽  
Left Hemisphere Stroke ◽  
Phonological Retrieval

Our understanding of post-stroke language recovery and underlying neuroplasticity is largely based on older age groups, who have increasing brain pathology and potentially more bilateral language functioning. We present the case of A., a 23 y.o. woman with chronic aphasia from a left-hemisphere stroke. Deterministic tractography indicated that A.’s language-relevant white matter structures were severely damaged. Using magnetoencephalography (MEG), we explored A.’s conceptual preparation and subsequent word planning abilities. Context-driven and Bare picture-naming tasks revealed substantial naming deficits, manifesting as word-finding difficulties and semantic paraphasias about half of the time. Naming was however facilitated by semantically constraining lead-in sentences. Altogether, this pattern indicates intact conceptual preparation but disrupted lexical and phonological retrieval abilities. MEG revealed that A.’s naming-related neural responses differed from that of a matched control. Source localisation showed active but differential recruitment of right-hemisphere structures (300-400 ms post-picture onset) during both correct naming (right temporo-parietal regions) and anomic (right inferior frontal gyrus) attempts. We consider that, despite A.’s young age, the presumed strong degree of language lateralisation and extensive structural damage limited her recovery. Although A.’s right hemisphere responded in a timely manner during word planning, its lexical and phonological retrieval abilities remained modest.

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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