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 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 Neural Signatures of Semantic and Phonemic Fluency in Young and Old Adults

2009 ◽  
Vol 21 (10) ◽  
pp. 2007-2018 ◽  
Author(s):  
Marcus Meinzer ◽  
Tobias Flaisch ◽  
Lotte Wilser ◽  
Carsten Eulitz ◽  
Brigitte Rockstroh ◽  
...  
Keyword(s):  
Brain Activity ◽  
Inferior Frontal Gyrus ◽  
Activity Patterns ◽  
Age Groups ◽  
Significant Drop ◽  
Old Adults ◽  
Word Finding ◽  
Retrieval Processes ◽  
Phonemic Fluency ◽  
Frontal Activity

As we age, our ability to select and to produce words changes, yet we know little about the underlying neural substrate of word-finding difficulties in old adults. This study was designed to elucidate changes in specific frontally mediated retrieval processes involved in word-finding difficulties associated with advanced age. We implemented two overt verbal (semantic and phonemic) fluency tasks during fMRI and compared brain activity patterns of old and young adults. Performance during the phonemic task was comparable for both age groups and mirrored by strongly left-lateralized (frontal) activity patterns. On the other hand, a significant drop of performance during the semantic task in the older group was accompanied by additional right (inferior and middle) frontal activity, which was negatively correlated with performance. Moreover, the younger group recruited different subportions of the left inferior frontal gyrus for both fluency tasks, whereas the older participants failed to show this distinction. Thus, functional integrity and efficient recruitment of left frontal language areas seems to be critical for successful word retrieval in old age.

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.

scholarly journals Right hemisphere grey matter structure and language outcomes in chronic left hemisphere stroke

Brain ◽  
2015 ◽  
Vol 139 (1) ◽  
pp. 227-241 ◽  
Author(s):  
Shihui Xing ◽  
Elizabeth H. Lacey ◽  
Laura M. Skipper-Kallal ◽  
Xiong Jiang ◽  
Michelle L. Harris-Love ◽  
...  
Keyword(s):  
Left Hemisphere ◽  
Grey Matter ◽  
Right Hemisphere ◽  
Language Outcomes ◽  
Left Hemisphere Stroke

scholarly journals Acquired dysgraphia in adults following right or left-hemisphere stroke

2014 ◽  
Vol 8 (3) ◽  
pp. 236-242 ◽  
Author(s):  
Jaqueline de Carvalho Rodrigues ◽  
Denise Ren da Fontoura ◽  
Jerusa Fumagalli de Salles
Keyword(s):  
Left Hemisphere ◽  
Phonological Processing ◽  
Word Processing ◽  
Right Hemisphere ◽  
Case Series ◽  
Lexical Route ◽  
Right Hemisphere Damage ◽  
Dual Route Model ◽  
Left Hemisphere Stroke ◽  
Graphemic Buffer

OBJECTIVE: This study aimed to assess the strengths and difficulties in word and pseudoword writing in adults with left- and right-hemisphere strokes, and discuss the profiles of acquired dysgraphia in these individuals.METHODS: The profiles of six adults with acquired dysgraphia in left- or right-hemisphere strokes were investigated by comparing their performance on word and pseudoword writing tasks against that of neurologically healthy adults. A case series analysis was performed on the patients whose impairments on the task were indicative of acquired dysgraphia.RESULTS: Two patients were diagnosed with lexical dysgraphia (one with left hemisphere damage, and the other with right hemisphere damage), one with phonological dysgraphia, another patient with peripheral dysgraphia, one patient with mixed dysgraphia and the last with dysgraphia due to damage to the graphemic buffer. The latter patients all had left-hemisphere damage (LHD). The patterns of impairment observed in each patient were discussed based on the dual-route model of writing.CONCLUSION: The fact that most patients had LHD rather than right-hemisphere damage (RHD) highlights the importance of the former structure for word processing. However, the fact that lexical dysgraphia was also diagnosed in a patient with RHD suggests that these individuals may develop writing impairments due to damage to the lexical route, leading to heavier reliance on phonological processing. Our results are of significant importance to the planning of writing interventions in neuropsychology.

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.

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 Effects of Direction and Index of Difficulty on Aiming Movements after Stroke

2014 ◽  
Vol 2014 ◽  
pp. 1-9
Author(s):  
Paola Ribeiro Coqueiro ◽  
Sandra Maria Sbeghen Ferreira de Freitas ◽  
Cassandra Mendes Assunção e Silva ◽  
Sandra Regina Alouche
Keyword(s):  
Left Hemisphere ◽  
Right Hemisphere ◽  
Movement Execution ◽  
Task Constraints ◽  
Aiming Movements ◽  
Brain Hemispheres ◽  
Hemisphere Lesion ◽  
Index Of Difficulty ◽  
And Gender ◽  
Left Hemisphere Stroke

Background.Brain hemispheres play different roles in the control of aiming movements that are impaired after unilateral stroke. It is not clear whether those roles are influenced by the direction and the difficulty of the task.Objective.To evaluate the influence of direction and index of difficulty (ID) of the task on performance of ipsilesional aiming movements after unilateral stroke.Methods.Ten individuals with right hemisphere stroke, ten with left hemisphere stroke, and ten age- and gender-matched controls performed the aiming movements on a digitizing tablet as fast as possible. Stroke individuals used their ipsilesional arm. The direction (ipsilateral or contralateral), size (0.8 or 1.6 cm), and distance (9 or 18 cm) of the targets, presented on a monitor, were manipulated and determined to be of different ID (3.5, 4.5, and 5.5).Results.Individuals with right hemisphere lesion were more sensitive to ID of the task, affecting planning and final position accuracy. Left hemisphere lesion generated slower and less smooth movements and was more influenced by target distance. Contralateral movements and higher ID increased planning demands and hindered movement execution.Conclusion.Right and left hemisphere damages are differentially influenced by task constraints which suggest their complementary roles in the control of aiming movements.

scholarly journals Right hemisphere structural adaptation and changing language skills years after left hemisphere stroke

Brain ◽  
2017 ◽  
Vol 140 (6) ◽  
pp. 1718-1728 ◽  
Author(s):  
Thomas M. H. Hope ◽  
Alex P. Leff ◽  
Susan Prejawa ◽  
Rachel Bruce ◽  
Zula Haigh ◽  
...  
Keyword(s):  
Left Hemisphere ◽  
Right Hemisphere ◽  
Language Skills ◽  
Structural Adaptation ◽  
Left Hemisphere Stroke

scholarly journals Shared and Distinct Neuroanatomic Regions Critical for Tool-related Action Production and Recognition: Evidence from 131 Left-hemisphere Stroke Patients

2015 ◽  
Vol 27 (12) ◽  
pp. 2491-2511 ◽  
Author(s):  
Leyla Y. Tarhan ◽  
Christine E. Watson ◽  
Laurel J. Buxbaum
Keyword(s):  
Left Hemisphere ◽  
Mirror Neuron System ◽  
Inferior Frontal Gyrus ◽  
Occipital Cortex ◽  
Neural Substrates ◽  
Middle Temporal Gyrus ◽  
Stroke Patients ◽  
Middle Temporal ◽  
Impaired Performance ◽  
Left Hemisphere Stroke

The inferior frontal gyrus and inferior parietal lobe have been characterized as human homologues of the monkey “mirror neuron” system, critical for both action production (AP) and action recognition (AR). However, data from brain lesion patients with selective impairment on only one of these tasks provide evidence of neural and cognitive dissociations. We sought to clarify the relationship between AP and AR, and their critical neural substrates, by directly comparing performance of 131 chronic left-hemisphere stroke patients on both tasks—to our knowledge, the largest lesion-based experimental investigation of action cognition to date. Using voxel-based lesion-symptom mapping, we found that lesions to primary motor and somatosensory cortices and inferior parietal lobule were associated with disproportionately impaired performance on AP, whereas lesions to lateral temporo-occipital cortex were associated with a relatively rare pattern of disproportionately impaired performance on AR. In contrast, damage to posterior middle temporal gyrus was associated with impairment on both AP and AR. The distinction between lateral temporo-occipital cortex, critical for recognition, and posterior middle temporal gyrus, important for both tasks, suggests a rough gradient from modality-specific to abstract representations in posterior temporal cortex, the first lesion-based evidence for this phenomenon. Overall, the results of this large patient study help to bring closure to a long-standing debate by showing that tool-related AP and AR critically depend on both common and distinct left hemisphere neural substrates, most of which are external to putative human mirror regions.

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