Hemisphere Lesions Research Articles

Preservation of Bilateral Corticospinal Projections from Injured Hemisphere After Perinatal Stroke

Background: Perinatal brain injury is a leading cause of developmental disabilities, including cerebral palsy. However, further work is needed to understand early brain development in the presence of brain injury. In this case report, we examine the longitudinal neuromotor development of a term infant following a significant loss of right-hemispheric brain tissue due to a unilateral ischemic stroke. Our analysis focuses on the integrity and development of the corticospinal tract (CST) from the lesioned hemisphere. This case provides a unique opportunity to evaluate CST development after loss of the majority of the motor cortex. Methods: Evaluations were conducted when the infant was 4 (Visit-1), 18 (Visit 2), and 25 (Visit 3) months old. Assessments included magnetic resonance imaging (MRI) to characterize the lesion and quantify CST structural integrity, single-pulse transcranial magnetic stimulation (spTMS) to evaluate CST functional circuitry, and neuromotor assessments. Results: At Visit 1, bilateral CSTs were identified through diffusion-weighted MRI (dMRI) despite an estimated loss of 92.7% (7.3% retained) of age-typical motor cortex from the right hemisphere. Both hemispheres exhibited bilateral motor-evoked potential in response to stimulation with spTMS, which remained when reassessed at Visits 2 and 3. Longitudinal MRI showed distinct developmental trajectories of CST integrity in each hemisphere, with the lesioned hemisphere exhibiting initial increases in integrity between Visits 1 and 2 followed by a decrease in integrity between Visits 2 and 3. The non-lesioned hemisphere showed increased integrity from Visit 1 to Visit 2, which remained stable at Visit 3. Motor assessments at all visits indicated a high risk of cerebral palsy. Conclusions: This report highlights the utility of MRI and spTMS in studying neuromotor development. The findings reveal preserved functional bilateral CST circuitry despite majority loss of the right-hemispheric motor cortex as well as distinct developmental trajectories in CST integrity between hemispheres. These results underscore the potential for neural plasticity after perinatal brain injury. Clinical Trials Registration: NCT05013736.

Right brain hemisphere lesions affecting language functioning in the acute phase of stroke recovery: A Croatian survey.

To investigate language impairments in the acute phase of stroke using a Croatian standardized language battery for the first time and compare patients with RBH stroke, LBH stroke and healthy individuals. This study compares language functioning in three groups of conveniently sampled participants: RBH stroke patients, LBH stroke patients and healthy individuals. Kruskal Wallis H test was used to evaluate a combined group comparison, after which a post-hoc Dunn test was performed. Patients with RBH stroke scored significantly lower than healthy individuals on the CAT:HR in verbal fluency, comprehension of written sentences, naming, and total production. In addition, comprehension of written and spoken sentences did not differ between patients with RBH and LBH stroke patients which suggests the existence of language impairment (p>.05). RBH stroke can significantly impair language comprehension and production in the acute phase of stroke recovery emphasizing the importance of early detection.

Epileptiform discharges in the context of self-limited pediatric focal epilepsy (EDSelFEC) in pediatric hemispherotomy patients: Role of white matter abnormalities.

To investigate the frequency of epileptiform discharges associated with self-limited focal epilepsy (EDSelFEC) in children who have undergone a hemispherotomy and to evaluate whether patients with coexistence of EDSelFEC and structural hemispheric epilepsies differ from patients without coexistence of EDSelFEC and whether there are differences between the two groups with regard to preoperative management and postoperative outcome. Data on 131 children who underwent a hemispherotomy between January 1999 and January 2015 were retrieved from the Epilepsy center's epilepsy surgery database. Children with EDSelFEC were compared with children without EDSelFEC with respect to epileptogenic hemispheric pathology, family history, age at epilepsy onset, timing of surgery, lesion laterality, preoperative cognitive function, response to sodium channel blocker antiepileptic medication, and surgical outcome. Parental consent was obtained. EDSelFECs were present in the EEG in 27 (21%) of the 131 cases. None of the patients had seizures associated with EDSelFECs. The percentages of EDSelFECs varied between pathology groups: vascular lesions: 38%, focal cortical dysplasia: 16%, polymicrogyria: 5%, Rasmussen encephalitis: 10%, hemimegalencephaly: 8%, mild malformation of cortical development with oligodendroglial hyperplasia:20%, other pathologies: 22%. EDSelFEC in the vascular group were significantly correlated with MRI changes showing white matter damage in addition to cortical damage (p =.02). 82.1% of EDSelFEC were located multifocal versus 4.8% multifocality in EDs other than EDSelFEC. EDSelFEC were significantly more often exacerbated by sodium channel blockers than EDs caused by structural (cortical) lesions. No differences were found between EDSelFEC+ and EDSelFEC- patients with respect to other variables studied. A significant number of children with hemispheric epileptogenic lesions, particularly children with pre-/perinatal vascular lesions, hemiplegia, and white matter lesions in addition to cortical lesions, presented with coexisting EDSelFEC.

Inner dialogue dysfunction and the abusive comments of the dominant hemisphere

ABSTRACT Inner dialogue and inner speech are normal systems of cerebral intrapersonal communication, crucial to self-awareness. Lesions affecting the cerebral network involved in these systems have been associated with the occurrence of Auditory Verbal Hallucinations (AVHs). These are regarde as a continuum phenomenon experienced by healthy, individuals, as well as those with psychiatric disorders. In this paper, two patients with left hemispheric lesions of different pathologies, vascular and tumor, respectively, who during their recovery of motor and sensory functions presented severe deregulation in their inner dialogue. In both cases, the damaged left dominant hemisphere adopted arrogant, demeaning, and abusive inner speech, while the right non-dominant side, which commands the rehabilitation of the lost functions, was subdued and quiet. This abusive unilateral inner dialogue was present until adequate recovery of independent functions was achieved for both patients.

Adaptive Compensatory Neurophysiological Biomarkers of Motor Recovery Post-Stroke: Electroencephalography and Transcranial Magnetic Stimulation Insights from the DEFINE Cohort Study.

This study aimed to explore longitudinal relationships between neurophysiological biomarkers and upper limb motor function recovery in stroke patients, focusing on electroencephalography (EEG) and transcranial magnetic stimulation (TMS) metrics. This longitudinal cohort study analyzed neurophysiological, clinical, and demographic data from 102 stroke patients enrolled in the DEFINE cohort. We investigated the associations between baseline and post-intervention changes in the EEG theta/alpha ratio (TAR) and TMS metrics with upper limb motor functionality, assessed using the outcomes of five tests: the Fugl-Meyer Assessment (FMA), Handgrip Strength Test (HST), Pinch Strength Test (PST), Finger Tapping Test (FTT), and Nine-Hole Peg Test (9HPT). Our multivariate models identified that a higher baseline TAR in the lesioned hemisphere was consistently associated with poorer motor outcomes across all five assessments. Conversely, a higher improvement in the TAR was positively associated with improvements in FMA and 9HPT. Additionally, an increased TMS motor-evoked potential (MEP) amplitude in the non-lesioned hemisphere correlated with greater FMA-diff, while a lower TMS Short Intracortical Inhibition (SICI) in the non-lesioned hemisphere was linked to better PST improvements. These findings suggest the potential of the TAR and TMS metrics as biomarkers for predicting motor recovery in stroke patients. Our findings highlight the significance of the TAR in the lesioned hemisphere as a predictor of motor function recovery post-stroke and also a potential signature for compensatory oscillations. The observed relationships between the TAR and motor improvements, as well as the associations with TMS metrics, underscore the potential of these neurophysiological measures in guiding personalized rehabilitation strategies for stroke patients.

Iowa Brain‐Behavior Modeling Toolkit: An Open‐Source MATLAB Tool for Inferential and Predictive Modeling of Imaging‐Behavior and Lesion‐Deficit Relationships

ABSTRACTThe traditional analytical framework taken by neuroimaging studies in general, and lesion‐behavior studies in particular, has been inferential in nature and has focused on identifying and interpreting statistically significant effects within the sample under study. While this framework is well‐suited for hypothesis testing approaches, achieving the modern goal of precision medicine requires a different framework that is predictive in nature and that focuses on maximizing the predictive power of models and evaluating their ability to generalize beyond the data that were used to train them. However, few tools exist to support the development and evaluation of predictive models in the context of neuroimaging or lesion‐behavior research, creating an obstacle to the widespread adoption of predictive modeling approaches in the field. Further, existing tools for lesion‐behavior analysis are often unable to accommodate categorical outcome variables and often impose restrictions on the predictor data. Researchers therefore often must use different software packages and analytical approaches depending on (a) whether they are addressing a classification versus regression problem and (b) whether their predictor data correspond to binary lesion images, continuous lesion‐network images, connectivity matrices, or other data modalities. To address these limitations, we have developed a MATLAB software toolkit that supports both inferential and predictive modeling frameworks, accommodates both classification and regression problems, and does not impose restrictions on the modality of the predictor data. The toolkit features both a graphical user interface and scripting interface, includes implementations of multiple mass‐univariate, multivariate, and machine learning models, features built‐in and customizable routines for hyper‐parameter optimization, cross‐validation, model stacking, and significance testing, and automatically generates text‐based descriptions of key methodological details and modeling results to improve reproducibility and minimize errors in the reporting of methods and results. Here, we provide an overview and discussion of the toolkit's features and demonstrate its functionality by applying it to the question of how expressive and receptive language impairments relate to lesion location, structural disconnection, and functional network disruption in a large sample of patients with left hemispheric brain lesions. We find that impairments in expressive versus receptive language are most strongly associated with left lateral prefrontal and left posterior temporal/parietal damage, respectively. We also find that impairments in expressive vs. receptive language are associated with partially overlapping patterns of fronto‐temporal structural disconnection and with similar functional networks. Importantly, we find that lesion location and lesion‐derived network measures are highly predictive of both types of impairment, with predictions from models trained on these measures explaining ~30%–40% of the variance on average when applied to data from patients not used to train the models. We have made the toolkit publicly available, and we have included a comprehensive set of tutorial notebooks to support new users in applying the toolkit in their studies.

The hypointense pulvinar sign on susceptibility weighed magnetic resonance imaging: A visual biomarker for iron deposition in epilepsy

Objective Our study aimed to investigate potential alterations in iron deposition within pulvinar, using susceptibility weighted imaging (SWI) MRI in epilepsy patients through a biomarker termed the “hypointense pulvinar sign.” Methods A full-text radiological information system search of radiological reports was performed for the term “epilepsy” between 2014 and 2022. Only patients with the diagnosis of epilepsy were included. SWI was assessed by two readers recording lateralization of an asymmetrically more hypointense pulvinar. Cohen’s kappa for inter-rater reliability was calculated. Fisher’s exact test was performed to assess for significance between groups. Results Our epilepsy cohort comprised 105 patients with following diagnoses: 45 intra-axial tumor, 13 meningioma, 13 MRI negative, 12 encephalomalacia, seven siderosis, six cavernoma, five arteriovenous malformation, two acute demyelinating encephalomyelitis, one tuberous sclerosis, one giant aneurysm. The hypointense pulvinar sign was correct in 44% of cases. Notably, right hemispheric lesions exhibited a significantly higher proportion of correct hypointense pulvinar signs compared to the left hemisphere (46% vs 24%; p = 0.044). Inter-rater reliability was substantial at 0.62 ( p < 0.001). Only two of 21 (10%) of healthy controls demonstrated a hypointense pulvinar sign, which was significantly different from the epilepsy cohort ( p < 0.01). Conclusions The hypointense pulvinar sign has proven to be a reproducible, simple to use biomarker for iron deposition in epilepsy which could be considered for inclusion into multimodal precision medicine models.

Structural Coupling System for Cognitive Modeling in Immersive VR Assessment Tasks

Unilateral spatial neglect (USN) is a disorder characterized by the inability to attend to the space opposite the cerebral hemisphere lesion, significantly hindering daily activities. Due to the complex neural circuitry of the brain, understanding the mechanisms of USN has proven challenging. In clinical settings, the Behavioral Inattention Test (BIT), a paper-based examination, is commonly used to assess USN. However, improved scores on this test do not necessarily guarantee functional improvement, as it solely evaluates performance in a two-dimensional space. To address this limitation, various approaches utilizing information and communication technology (ICT) and measurement devices in rehabilitation engineering have been proposed. However, related studies have focused on analyzing motor responses to specific sensory stimuli, and the assessment measures often fail to capture a patient’s symptoms in dynamic environments. Therefore, this study proposes a methodology for modeling human spatial cognition. This cognitive architecture utilizes a structural coupling system that integrates parameters from multiple computational intelligence subsystems. In this study, we constructed a simulation environment capable of replicating the movements of patients with USN using empirical data collected from actual experiments. Furthermore, in this simulation environment, we developed patient agents that incorporated the proposed cognitive architecture. The experimental results suggest that hypothesis testing concerning attention mechanisms can be applied through the performance of patient agents within the simulation environment.

NOT THE USUAL SUSPECTS: GLIOBLASTOMA OF THE CEREBELLOPONTINE ANGLE MASQUERADING AS A VESTIBULAR SCHWANNOMA

Introduction Most tumoral processes involving the cerebellopontine angle (CPA) are extraneuraxial and usually comprise of vestibular schwannomas and meningiomas, followed by less common lesions such as epidermoid cysts, metastases and arachnoid cysts. Glioblastomas located in the CPA are rarely diagnosed. Uncommonly, intraneuraxial tumors in the CPA may grow in an exophytic manner compressing the surrounding cranial nerves, resembling the clinical picture of a more common extraneuraxial tumour. Clinical Case A 47 year old male presented to our department accusing gait imbalance, vertigo, vomiting and nausea, symptoms that started 2 months prior to admission. Upon neurological examination, the patient additionally presented right facial paresis and hypoesthesia, right sided hypoacusis, hypogeusia and diplopia. A contrast enhanced cerebral MRI revealed a right cerebellopontine angle mass with inhomogenous contrast enhancement, relatively well delineated, exerting mass effect on the cerebellum and pons with reduced perilesional edema but with involvement of the internal acoustic meatus. The indication for surgical removal of the tumour was made. The patient was placed in sitting position and a right retrosigmoid approach was performed using the operating microscope. Upon retraction of the cerebellar hemisphere, a greyish, highly vascularized and soft lesion was seen, exhibiting a spread growth, engulfing the V, VII and VIII nerves, without infiltrating them, resembling anything but a schwannoma. A frozen section of the tumour revealed a surprising result: high grade glioma. The surgical excision continued in a piece-meal fashion, using the ultrasonic aspirator with preservation of the cranial nerves until an almost complete removal was achieved. The immediate postop evolution of the patient was favourable. Nevertheless, the final histopathological diagnosis confirmed a grade IV glioblastoma. Oncological treatmend followed, but the tumour relapsed in 2 months after surgery, the control MRI revealing a multilocular tumoral dissemination in the cerebellum and brainstem which was surgically unsalvageable. Conclusion Glioblastoma of the CPA, manifesting both imagistically and clinically as a vestibular schwannoma is a rare entity but nevertheless extant, that dramatically changes the prognosis and postop evolution of a patient. Physicians involved in the diagnosis and treatment of such tumours must always be suspicious of the usual suspects in the CPA.

NCOG-06. FACTORS ASSOCIATED WITH SOCIAL DISABILITY IN THE CHRONIC POSTOPERATIVE PERIOD IN PATIENTS WITH GLIOMAS

Abstract BACKGROUND Patients with low-grade gliomas may have no obvious problems during hospitalization or their initial return to social life; however, social life difficulties may gradually become more apparent long after the surgery. We investigated factors associated with social disabilities in patients with low-grade gliomas in the postoperative chronic phase. METHODS The study included 114 patients with WHO grade 2 or 3 gliomas who underwent surgery (mean age, 44.3±13.2 years). Seventy-six patients underwent an initial surgery and 38 underwent a second surgery. All patients underwent various brain functional assessments and interviews about their social lives over 1 year after the surgery (median, 23 months). Factors associated with social disabilities were determined using logistic multiple regression analysis and chi-square tests. Voxel-based lesion symptom mapping was used to examine the brain regions associated with social disabilities. RESULTS Social disabilities were observed in 12.3% of the patients. Factors associated with social disabilities were the number of surgeries (first vs. second, p=0.0052) and tumor location (left vs. right, p=0.0091). Patients with recurrence and right cerebral hemispheric lesions had a higher probability of social disability (42.1%, p<0.0001) than that of other patients. The reasons for social disability after right hemispheric recurrence were social behavior disorder (62.5%) and neuropsychological dysfunctions (37.5%). Social behavioral disorders include interpersonal problems, such as job switching owing to problems with others, poor interpersonal relationships, and sexually deviant behavior. No other apparent neuropsychological abnormalities were found in patients with social behavior disorders. Surgical resection of the deep part of the right prefrontal area is associated with social behavior disorders and right supplementary motor cortex resection is associated with neuropsychological disorders. CONCLUSION In lower grade glioma, patients with right hemispheric recurrence were more likely to develop social disabilities in the chronic phase, which was caused by social behavioral disorders and neuropsychological dysfunctions.

NCOG-36. CLINICAL AND DEMOGRAPHIC CHARACTERISTICS PREDICT POSTOPERATIVE BEHAVIORAL DYSFUNCTION FOLLOWING HIGH-GRADE (WHO 2-4) GLIOMA RESECTION

Abstract BACKGROUND Gliomas have the highest incidence (85%) of cancer-related cognitive and behavioral impairments. Few studies have explored preoperative clinical and demographic drivers/predictors of postoperative behavioral impairment. METHODS We analyzed prospectively collected data from patients 1) who underwent glioma (WHO 2-4) resection and 2) who had postoperative Flanker testing, an assessment of inhibitory control and selective attention (NIH Toolbox Cognition Battery). Patients whose age-adjusted Flanker score (last follow-up) was less than the cohort mean were classified as having “poor” outcomes. Univariate analysis, multivariate logistic, and LASSO regressions were performed to identify drivers of poor outcomes. RESULTS In total, 43 patients (mean age at diagnosis 45.9 [range 18-77] years, 35% female) met inclusion criteria. The average age-adjusted Flanker score was 83.3±13.6; twenty (46.5%) patients had below-average scores. On univariate analysis, there were no significant differences in demographic factors (age, sex, education, employment) and tumor characteristics (grade, location). Multivariate logistic regression identified having high school versus higher degree (OR:1.6x10^4, p=0.017), WHO Grade 4 versus Grade 2 (OR:2.36, p=0.026), and parietal lesion (OR:1.6x10^3, p=0.034) as risk factors, while increased age (OR per 1-year increase:0.71, p=0.009) and dominant language hemisphere lesion (OR 0.002, p=0.048) were protective against poor behavioral outcome. LASSO regression (efficiently narrows down predictors) identified higher WHO grade (4 vs. 2), lower education (high school vs. higher), and insular and parietal lesions as predictive of poor outcomes. Increased age at diagnosis, frontal lobe lesions, and lesions on the dominant language hemisphere were protective. CONCLUSION Lower education status, higher WHO grade, and insular and parietal lesions are risk factors for poor behavioral outcomes postoperatively following glioma resection. In contrast, increased age, frontal lobe lesions, and dominant language hemisphere lesions were positive prognostic factors. Neuro-oncologists may use these findings to preoperatively counsel patients and tailor care plans with necessary postoperative support.

Iowa Brain-Behavior Modeling Toolkit: An Open-Source MATLAB Tool for Inferential and Predictive Modeling of Imaging-Behavior and Lesion-Deficit Relationships.

The traditional analytical framework taken by neuroimaging studies in general, and lesion-behavior studies in particular, has been inferential in nature and has focused on identifying and interpreting statistically significant effects within the sample under study. While this framework is well-suited for hypothesis testing approaches, achieving the modern goal of precision medicine requires a different framework that is predictive in nature and that focuses on maximizing the predictive power of models and evaluating their ability to generalize beyond the data that were used to train them. However, few tools exist to support the development and evaluation of predictive models in the context of neuroimaging or lesion-behavior research, creating an obstacle to the widespread adoption of predictive modeling approaches in the field. Further, existing tools for lesion-behavior analysis are often unable to accommodate categorical outcome variables and often impose restrictions on the predictor data. Researchers therefore often must use different software packages and analytical approaches depending on whether they are addressing a classification vs. regression problem and on whether their predictor data correspond to binary lesion images, continuous lesion-network images, connectivity matrices, or other data modalities. To address these limitations, we have developed a MATLAB software toolkit that supports both inferential and predictive modeling frameworks, accommodates both classification and regression problems, and does not impose restrictions on the modality of the predictor data. The toolkit features both a graphical user interface and scripting interface, includes implementations of multiple mass-univariate, multivariate, and machine learning models, features built-in and customizable routines for hyper-parameter optimization, cross-validation, model stacking, and significance testing, and automatically generates text-based descriptions of key methodological details and modeling results to improve reproducibility and minimize errors in the reporting of methods and results. Here, we provide an overview and discussion of the toolkit features and demonstrate its functionality by applying it to the question of how expressive and receptive language impairments relate to lesion location, structural disconnection, and functional network disruption in a large sample of patients with left hemispheric brain lesions. We find that impairments in expressive vs. receptive language are most strongly associated with left lateral prefrontal and left posterior temporal/parietal damage, respectively. We also find that impairments in expressive vs. receptive language are associated with partially overlapping patterns of fronto-temporal structural disconnection, and that the associated functional networks are also similar. Importantly, we find that lesion location and lesion-derived network measures are highly predictive of both types of impairment, with predictions from models trained on these measures explaining ~30-40% of the variance on average when applied to data from patients not used to train the models. We have made the toolkit publicly available, and we have included a comprehensive set of tutorial notebooks to support new users in applying the toolkit in their studies.

Bihemispheric IDH-Wildtype Glioblastoma with Unilateral FGFR3-TACC3 Fusion in Patient with Breast Cancer History: A Case Report and Literature Review

Abstract Introduction/Objective Adult IDH-wild type glioblastomas comprise a heterogeneous spectrum of neoplasms, characterized by poor prognosis and resistance to the chemoradiotherapy. For WHO integrated diagnosis classification and to establish treatment options, molecular analysis is necessary. Herein, we present a case of a glioblastoma, IDH-wildtype with involvement of both cerebral hemispheres and an uncharacteristic in-frame fusion limited to one hemisphere. Methods/Case Report The patient is a 52-year-old woman with past medical history of metastatic breast cancer who presented with headache and worsening facial pain. Brain magnetic resonance imaging brain demonstrated a right frontal lobe lesion with vasogenic edema. The patient was treated with Gamma Knife radiosurgery. Scans revealed enlargement and a new left frontal lobe lesion. Bihemispheric tumor resection and GammaTile placement was undertaken. Results (if a Case Study enter NA) Histologically, the tumor was composed of hypercellular astrocytes, microvascular proliferation, and necrosis with no evidence of metastatic disease. Immunohistochemistically, neoplastic cells showed glial fibrillary acidic protein expression and elevated Ki-67 proliferation index. Molecular examination revealed in the right hemisphere lesion post-radiation (1) FGFR3::TACC3 (exon 17::exon 11) fusion and (2) TERT promoter, while the left hemisphere lesion which did not receive radiation showed clinically relevant variants in (1) TERT promoter, (2) TP53, (3) NF1, and (3) PIK3CA without identification of a fusion. An integrated diagnosis of glioblastoma, IDH- wildtype, CNS WHO grade 4 was established bilaterally. Conclusion The fibroblast growth factor receptor 3 (FGFR3)-transforming acidic coiled-coil 3 (TACC3) fusion is identified as a rare molecular feature in glioblastomas with an estimated prevalence of 4%. Clinical trials suggest that F3T3-positive tumors have a better prognosis than those without the translocation. The identification of the oncogenic FGFR3-TACC3 fusion highlights the possibility of identifying patients potentially responsive to targeted therapy with FGFR kinase inhibitors. The significance of the molecular differences in the right and left hemisphere lesions is uncertain; glioblastomas are heterogeneous tumors with intra-and intertumoral heterogeneity but it may suggest independent origins.

Baseline Blood Pressure Was Associated with Hemispheric Cerebral Blood Flow in Acute Small Subcortical Infarcts

Introduction: While increased baseline blood pressure (BP) is a prevalent comorbidity in the acute phase of ischemic stroke, the association between baseline BP and the state of hemispheric perfusion in patients with acute small subcortical infarcts (SSIs) has not been studied in detail. The aim of this study was to investigate the relationship between baseline BP and hemispheric cerebral blood flow (CBF) in acute SSIs. Methods: This retrospective study included 101 patients with acute SSIs. Baseline hemispheric CBF was assessed through co-registration of baseline CT perfusion imaging and follow-up diffusion-weighted imaging. The association between baseline BP, CBF, and different cerebral small vessel disease (CSVD) biomarkers was assessed. Results: Baseline systolic BP (SBP) and diastolic BP (DBP) were negatively associated with contralateral hemispheric CBF after multivariate-adjusted linear analysis (SBP: β = −0.001, 95% CI: −0.002 to 0.000, p = 0.030; DBP: β = −0.002, 95% CI: −0.003∼0.001, p = 0.006). Among other CSVD biomarkers, the presence of any cerebral microbleeds showed a significant association with lower CBF in the contralateral hemisphere of the infarct lesion (r = −0.270, p = 0.035). Conclusion: In patients with acute SSIs, increased baseline BP was associated with reduced CBF in the contralateral hemisphere of the infarct lesion, which probably could be interpreted by the exacerbation of the CSVD burden, suggesting a potential mechanistic link between BP autoregulation dysfunction and the aggravation of neurovascular impairment in SSIs.

The effect of cerebellar lesıons on language in Turkısh speakıng indıvıduals

ABSTRACT Background The cerebellum is approximately 10% of the brain volume and is responsible for attention, language, emotion and cognitive functions. Linguistic processing difficulties and cognitive impairments may be observed in individuals with cerebellar lesions depending on the location and severity of the damage. There is no study evaluating language in Turkish-speaking individuals with cerebellar lesions. Objective To determine the differences in linguistic and visuospatial skills of Turkish speaking individuals with cerebellar lesions compared to control groups, including a right hemisphere lesion group and a healthy control group. Method Fifteen patients with cerebellar lesion (without hemispatial neglect and dysarthria), 15 patients with right hemisphere lesion due to right arter cerebri media (without hemispatial neglect) and 15 healthy control were included. To clarify the language impairment specific to cerebellar lesions, we also included individuals with right hemisphere lesions, which are typically assumed not to present with aphasia. The Language Assessment Test for Aphasia (ADD), Benton Judgment of Line Orientation Test, Benton Facial Recognition Test, Single Letter Deletion Test were used. The “Accident Scene” picture was used for collecting narrative speech samples. After a three group comparison a post-hoc pairwise analysis was performed. Results Among the microstructural parameters in the narrative language analysis, the effort ratio was significantly higher in the cerebellar lesion group compared to the healthy control group. Among the non-verbal cognitive tests, the Benton Facial Recognition Test score was significantly lower in the cerebellar and right hemisphere lesion group compared to the healthy control group. Total score, naming and grammar scores in the ADD test were significantly lower in the cerebellar lesion group compared with the healthy control group. There was no difference between cerebellar and right hemisphere lesions in terms of ADD score, ADD subtests and narrative parameters. Conclusion In Turkish-speaking individuals with cerebellar lesions, verbal productivity may be interrupted by effort behaviours, and standard aphasia assessment tests may reveal impaired grammar and naming performance without a diagnosis of aphasia. In addition to reduced efficiency in verbal production, facial recognition may be impaired. We found no difference between individuals with lesions in the cerebellum and right hemisphere. This suggests that ischemic damage may affect different components of language independently of the diagnosis of aphasia.

Disrupted white matter structural networks in patients with acute ischemic stroke in the right basal ganglia

Widespread structural changes have been observed in patients with stroke in previous diffusion tensor imaging studies. However, the topological organization of white matter structural networks after acute ischemic stroke (AIS) in the right basal ganglia (BG) remains unknown. The aim of our study is to investigate whether the topological structure of the white matter structural network is altered in patients with AIS in the right BG, and its relationship with cognition. Graph theoretical analysis was employed to investigate the topological architecture of whole-brain white matter structural networks in 40 AIS patients in the right BG and 40 healthy controls (HC), and network-based statistics (NBS) were applied to examine structural connectivity alterations. Compared to HC, AIS patients exhibited altered global network properties characterized by increased small-worldness, normalized clustering coefficient, and shortest path length, as well as decreased clustering coefficient, local efficiency, and global efficiency. The nodes with significantly decreased nodal properties in AIS patients were primarily located in the default mode network, limbic system, sensorimotor system, salience network, and central executive network. Reduced structural connectivity detected by NBS in AIS patients were primarily located in the lesional hemisphere. Furthermore, altered nodal properties were correlated with cognitive scores. Documenting the alterations in the topological patterns of white matter structural networks will help to promote the understanding of the neural mechanisms of cognitive impairment after AIS in the right BG.

Seizure Induced by Single-Pulse TMS Delivered to Lesioned Hemisphere in Stroke

Abstract Transcranial magnetic stimulation (TMS) is used for therapeutic and research purposes, but it is still important to establish safety guidelines and recommendations mainly related to serious adverse effect (SAE). As part of this, safety reports need to be published. Our report highlights a case of a male patient who was a 30-year-old with a history of hemorrhagic stroke following an accidental seizure episode during a single-pulse TMS.

Visual self-face and self-body recognition in a left-brain-damaged prosopagnosic patient.

The present case study describes the patient N.G., who reported prosopagnosia along with difficulty in recognising herself in the mirror following a left-sided temporo-occipital hemispheric stroke. The neuropsychological and experimental investigation revealed only a mild form of apperceptive prosopagnosia, without visual agnosia, primarily caused by an impaired visual processing of face-parts and body parts but not of full faces. Emotional expressions did not modulate her face processing. On the other hand, N.G. showed a marked impairment of visual self-recognition, as assessed with visual matching-to-sample tasks, both at the level of body-part and face-part processing and at a full-face level, featured by a deficit in the perceptual discrimination of her own face and body, as compared to the others' face and body. N.G.'s lesion mapping showed damage to the left inferior occipito-temporal cortex, affecting the inferior occipital gyrus and compromising long-range connections between the occipital/temporo-occipital areas and the anterior fronto-temporal areas. Overall, the present case report documents that visual processing of the person's own face may be selectively compromised by a left-sided hemispheric lesion disconnecting extra-striate body- and face-selective visual areas to self-representation regions. Moreover, others' (full) face processing may be preserved, as compared with the impaired ability to discriminate others' body and face parts.

The Impact of Stimulation Parameters on Cardiovascular Outcomes in Chronic Stroke Patients Following Transcranial Direct Current Stimulation-A Pilot Controlled, Randomized, Double-Blind Crossover Trial.

Stroke survivors often experience autonomic nervous system (ANS) dysfunction. While Transcranial Direct Current Stimulation (tDCS) has been shown to modulate the ANS when applied to the left hemisphere, its effects on the right hemisphere remain unexplored. We aimed to compare the effects of tDCS applied to both the injured and the contralateral hemispheres on heart rate variability (HRV) and functional capacity in individuals post-stroke. Twenty individuals with cerebral hemisphere lesions (ten with right-hemisphere lesions and ten with left-hemisphere lesions) were randomized into four groups: anodal and sham tDCS on the left temporal cortex (T3) and anodal and sham tDCS on the right temporal cortex (T4). HRV was assessed before the intervention, after the six-minute walk test (6MWT), and following tDCS. HRV data were categorized into frequency ranges: low frequency (LF), high frequency (HF), and sympathovagal balance. The 6MWT (meters) was conducted both pre- and post-tDCS. In individuals with right-hemisphere lesions, a higher global LF value was observed (right side: 71.4 ± 16.8 nu vs. left side: 65.7 ± 17.3 nu; p = 0.008), as well as lower values of the HF component (right side: 29.5 ± 18.9 nu vs. left side: 34.0 ± 17.4 nu; p = 0.047), consequently exhibiting higher global values of the low/high-frequency ratio (right side: 3.9 ± 2.8 vs. left side: 2.9 ± 2.4). Regarding the stimulation site, tDCS over T3 led to a lower overall value of the low/high-frequency ratio (left hemisphere: 3.0 ± 2.2 vs. right hemisphere: 3.7 ± 2.9; p = 0.040) regardless of the lesion location. A significant increase in the distance covered in the 6MWT was observed for individuals with lesions in both hemispheres after tDCS at T3. Participants with right-hemisphere lesions exhibited superior global sympathetic autonomic nervous system activity. When the tDCS was applied on the left hemisphere, it maintained lower sympathovagal balance values and improved functional capacity regardless of the hemisphere affected by the stroke.

Long-lasting pure topographical disorientation due to heading disorientation following left retrosplenial infarction: A report of two cases

Topographical disorientation is linked to lesions in the right hemisphere and typically resolves within a few months post-stroke. Persistent topographical disorientation is uncommon and frequently accompanied by impairments in visual memory, complicating the analysis of the underlying mechanisms. Herein, we report two cases of sustained pure topographical disorientation following cerebral hemorrhages in the left retrosplenial region. The patients exhibited disorientation in both familiar and unfamiliar settings, attributable to heading disorientation, a deficit in determining the directional relationship between one’s current position and a target location or external frames. The patients struggled with reconstructing large-scale spatial frameworks and integrating new egocentric and allocentric perspectives upon changes in body orientation. There were no landmark agnosia, egocentric disorientation, or anterograde disorientation. Although mild verbal memory deficits were observed, no other cognitive impairments, including visual memory deficits, were detected. Our findings imply that lesions confined to the left retrosplenial region can induce enduring heading disorientation and suggest a significant role for this area in processing and integrating spatial information necessary for large-scale navigation. Clarifying the features of topographical disorientation will significantly impact the therapeutic approaches, enhancing the quality of life for affected patients by restoring their independence and mobility.