Hemisphere Lesions Research Articles

THE DESCRIPTION OF INDEPENDENCE LEVEL OF POST-STROKE PATIENTS

Background: The main source of disability that prevents individuals from being independent in doing everyday activities is functional movement disorders caused by bodily weakness in stroke conditions. This study aims to find out the level of independence of post-stroke patients. Methods: This study employs a descriptive quantitative approach based on the level of independence, type of stroke, and the side of the brain that is affected by stroke patients in Jakarta. Physiotherapists served as the enumerators for the study, which lasted for two months. The data were collected by observing and interviewing patients using the Functional Independent Measure (FIM) instrument. Results: A total of 101 stroke patients, including 78 ischemic stroke patients and 23 hemorrhagic stroke patients, were included in this study. A total of 40 individuals have left hemispheric lesions, of which 35 have ischemic types and 5 have hemorrhagic types. The overall number of patients with right hemisphere lesions is 61; of these, 43 have ischemic types and 18 have hemorrhagic types. Hemorrhagic stroke has a level of independence of 4.16 (SD + 1.06), while the ischemic stroke has a level of independence of 4.69 (SD +0.80). Ischemic stroke patients have a higher total FIM score than hemorrhagic stroke patients. Conclusion: Patients with ischemic stroke have a better level of independence than those with hemorrhagic stroke.

Abstract- Poster

Abstract- Poster

Correlation of Hemispatial Neglect with White Matter Tract Integrity: A DTI Study.

We investigated the diffusion tensor image (DTI) parameters of superior longitudinal fasciculus (SLF) and inferior fronto-occipital fasciculus (IFOF), and their relationships with hemispatial neglect. Thirteen patients with first-ever ischemic stroke who had the right hemispheric lesion were included. Neglect was assessed using the Albert test and figure discrimination test of Motor-free Visual Perception Test 3 (MVPT-3). The SLF and IFOF were separated by diffusion tensor tractography (DTT) and tract volume (TV) was calculated. We measured the fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values in the total area, seed region of interest (ROI), and target ROI, respectively. Among thirteen patients, seven demonstrated signs of hemispatial neglect on neglect test. Tractography reconstruction showed significantly low TV of the right IFOF in patients with hemispatial neglect. FA values of the right SLF and the right IFOF were significantly lower in neglect patients. ADC values were not significantly different in two groups. This study suggests that damage of SLF and IFOF is associated with hemispatial neglect in right hemispheric stroke patients. DTI may be useful for predicting the severities of hemispatial neglect using values such as TV and FA of each tract.

Segregated circuits for phonemic and semantic fluency: A novel patient-tailored disconnection study

Phonemic and semantic fluency are neuropsychological tests widely used to assess patients’ language and executive abilities and are highly sensitive tests in detecting language deficits in glioma patients. However, the networks that are involved in these tasks could be distinct and suggesting either a frontal (phonemic) or temporal (semantic) involvement.42 right-handed patients (26 male, mean age = 52.5 years, SD=±13.3) were included in this retrospective study. Patients underwent awake (54.8%) or asleep (45.2%) surgery for low-grade (16.7%) or high-grade-glioma (83.3%) in the frontal (64.3%) or temporal lobe (35.7%) of the left (50%) or right (50%) hemisphere. Pre-operative tractography was reconstructed for each patient, with segmentation of the inferior fronto-occipital fasciculus (IFOF), arcuate fasciculus (AF), uncinate fasciculus (UF), inferior longitudinal fasciculus (ILF), third branch of the superior longitudinal fasciculus (SLF-III), frontal aslant tract (FAT), and cortico-spinal tract (CST). Post-operative percentage of damage and disconnection of each tract, based on the patients’ surgical cavities, were correlated with verbal fluencies scores at one week and one month after surgery. Analyses of differences between fluency scores at these timepoints (before surgery, one week and one month after surgery) were performed; lesion-symptom mapping was used to identify the correlation between cortical areas and post-operative scores.Immediately after surgery, a transient impairment of verbal fluency was observed, that improved within a month. Left hemisphere lesions were related to a worse verbal fluency performance, being a damage to the left superior frontal or temporal gyri associated with phonemic or semantic fluency deficit, respectively. At a subcortical level, disconnection analyses revealed that fluency scores were associated to the involvement of the left FAT and the left frontal part of the IFOF for phonemic fluency, and the association was still present one month after surgery. For semantic fluency, the correlation between post-surgery performance emerged for the left AF, UF, ILF and the temporal part of the IFOF, but disappeared at the follow-up.This approach based on the patients’ pre-operative tractography, allowed to trace for the first time a dissociation between white matter pathways integrity and verbal fluency after surgery for glioma resection. Our results confirm the involvement of a frontal anterior pathway for phonemic fluency and a ventral temporal pathway for semantic fluency. Finally, our longitudinal results suggest that the frontal executive pathway requires a longer interval to recover compared to the semantic one.

Латерализация слухоречевой асимметрии при афазических расстройствах и ее влияние на эффективность дихотического прослушивания серий односложных слов и динамику восстановления речи

The dichotic listening task is commonly used in a wide range of neuropsychological issues for studying interhemispheric asymmetry and interhemispheric interaction mechanisms. The article aims to determine the specific vector of auditory speech asymmetry for efferent motor and acoustic mnestic aphasia and its correlation with the dynamics of speech recovery. The paper studied the frequency of the right and left vectors of auditory speech asymmetry in aphasics with different time post-onset and structural characteristics of lesions. Also, the paper analyses the influence of the ear advantage side on the efficiency index of dichotic listening and quantitative indicators of speech. Material. Patients with acoustic mnestic (n = 52) and efferent motor aphasia (N = 58) of moderate and mild severity. Methods. The dichotic listening task: 16 paired series of 4 monosyllabic words in each. Results. Time post-onset, as well as lesion size, does not influence directly auditory speech laterality in aphasics. The frequency of occurrence of the positive and negative signs of the coefficient of the right ear has no pronounced differences between the different lesion sizes and time post-onset in aphasia. The left hemisphere lesion marks the impairment of the reciprocity in hemispheric interaction. The left ear advantage influences positively the dichotic listening efficiency index. Aphasia recovery does not have a direct conjugacy with the side of lesion or ear advantage. At the same time, the left ear advantage in acoustic mnestic aphasia creates a more pronounced “positive shift” in speech scores than in efferent motor aphasia. Conclusion. It appears that interhemispheric speech reorganization is determined apart from topical, typological, time post-onset and the left-handedness factors by others that needed to be investigated.

Impact of hemisphere localization and the frequency of physical and occupational therapy sessions on functional independence of stroke patients in inpatient rehabilitation

To determine whether the lesioned hemisphere and the frequency of physical and occupational therapy sessions in inpatient rehabilitation have effects on the functional independence of stroke patients.

Simultaneously stimulating both brain hemispheres by rTMS in patients with unilateral brain lesions decreases interhemispheric asymmetry.

Interhemispheric asymmetry caused by brain lesions is an adverse factor in the recovery of patients with neurological deficits. Repetitive transcranial magnetic stimulation (rTMS) has been shown to modulate cortical oscillation and proposed as an approach to rebalance the symmetry, which has not been documented well. In this study, we investigated the influence of repetitive transcranial magnetic stimulation (rTMS) on EEG power in patients with unilateral brain lesions by simultaneously stimulating both brain hemispheres and to elucidate asymmetrical changes in rTMS-induced neurophysiological activity. Fourteen patients with unilateral brain lesions were treated with one active and one sham session of 10 Hz rTMS over the vertex (Cz position). Resting-state EEGs were recorded before and immediately after rTMS. The brain symmetry index (BSI), calculated from a fast Fourier transform, was employed to quantify the power asymmetry in both hemispheres and paired channels over the entire range and five frequency bands (delta, theta, alpha, beta and gamma bands). Comparison between active and sham sessions demonstrated rTMS-induced EEG after-effects. rTMS in the active session significantly reduced the BSI in patients with unilateral brain lesions over the entire frequency range (t = 2.767, P = 0.016). Among the five frequency bands, rTMS only induced a noticeable decrease in the BSI in the delta band (t = 2.254, P = 0.042). Furthermore, analysis of different brain regions showed that significant changes in the BSI of the alpha band were only demonstrated in the posterior parietal lobe. In addition, EEG topographic mapping showed a decreased power of delta oscillations in the ipsilesional hemisphere, whereas distinct cortical oscillations were observed in the alpha band around the parietal-occipital lobe in the contralesional hemisphere. When both brain hemispheres were simultaneously activated, rTMS decreased interhemispheric asymmetry primarily via reducing the delta band in the lesioned hemisphere.

Changes in autonomic control of heart rate after ischemic cerebral stroke

Heart rate variability (HRV) is a physiological phenomenon which reflects the influence of the autonomic nervous system on the heart work. Likewise acute MI, acute ischemic stroke leads to autonomic dysbalance and lowered HRV. However, literature relevant data on autonomic dysbalance after the acute phase of ischemic stroke. The aim of this study was to assess the level of autonomic dysbalance in patients after the acute phase of ischemic stroke. This prospective study included 54 consecutive patients who had suffered ischemic stroke (31 men and 23 women, mean age 54 ± 11 years) and 54 age-matched healthy control subjects (37 men and 17 women, mean age 51 ± 6 years). In the acute phase of the disease, along with clinically manifest neurologic deficit, there is ischemic hemispheric lesion verified by computed tomography (CT) scan. Lesion of the left and right cerebral hemisphere was detected in 51% and 49% of patients, respectively. Twenty-four hour Holter ECG was performed 58 ± 23 days after the stroke (14 ± 5 days from the beginning of rehabilitation). HRV was analyzed from the Holter ECG data. The values of the HRV parameters in stroke patients were compared with those recorded in the control group. Patients who had suffered an ischemic stroke had a significantly lower overall HRV and shorter mean RR interval than healthy subjects from the control group: SDNN 96 ± 27 vs. 136 ± 31 ms, P < 0.001; TP 1962 ± 1338 vs. 3968 ± 2857 ms, P < 0.001; and mean RR 869 ± 104 vs. 892 ± 117 ms, P = 0.02. As in MI, the values of HRV stay significantly lower after the acute phase of the disease in patients who have suffered ischemic stroke compared to healthy persons of the same age.

A comparative study betwee Medulloblastoma And Cerebellar astrocytoma In children

study was conducted between 2000 & 2002, 50 children with histopathologyically verified medulloblastoma and cerebellar astrocytoma in neurosurgical department of Surgical Specialties Hospital. Ages ranged from 2-19 years, peak incidence between 5-10 years. No significant gender differences found. CT scan confirmed features of medulloblastoma: midline location, well defined margin & hyperdensity of lesion with homogenous enhancement after I.V. contrast infusion. In cerebellar astrocytoma, 60% were midline tumor, most of which were solid & 40% were hemispheric lesion, most of which were cystic. Calcification on CT scans seen more in medulloblastoma.Shunt operation was the main procedure conducted for treatment of hydrocephalus associated with these tumors, but other CSF diversion procedures, especially safety burrhole at time of tumor resection was carried on in cystic lesion located off the midline. Total removal was achieved in 46.7% of children with medulloblastomas & 50% of children with cerebellar astrocytomas. Brain stem violation was evident more in medulloblastoma & was the main factor behind the incomplete tumor removal in significant number of cases that adversely affected the outcome. postoperative complications (pseudomeningocele, cerebellar mutism, meningitis, CSF leak, cranial nerve palsy…etc.) encountered more in children with medulloblastoma. Mortality rate was 6.7% in medulloblastomas & 10% in cerebellar astrocytoma. The cause of death in patients with medulloblastoma was meningitis & patients with cerebellar astrocytomas was brain stem injury. early diagnosis & total removal of tumor with proper postoperative care would essentially decrease the postoperative morbidity & mortality

Tocilizumab for severe refractory primary central nervous system vasculitis: A center experience.

Primary Central Nervous System Vasculitis (PCNSV) is responsible for 3%-5% of strokes before age 50. It presents with clinical, radiological, and pathological variability. Optimal management is unknown given the absence of randomized clinical trials. Explore whether tocilizumab, an anti-interleukin-6 monoclonal antibody, is an effective treatment for refractory PCNSV. Patients with PCNSV treated with tocilizumab in a single tertiary center were reviewed. Three patients were identified. In two of them, MRI-revealed ischemic lesions. The other presented with a subcortical hemispheric pseudotumoral lesion. Brain biopsy was inconclusive in two patients. Due to a significant number of relapses and clinical deterioration despite other immunosuppressive drugs, tocilizumab was initiated and induced a long remission period up to 44months. Observed side effects were a fungic infection, neutropenia and thrombocytopenia (both transitory), and a pulmonary embolism in one of the cases. Tocilizumab might be a therapeutic option for PCNSV (Class IV evidence), given its efficacy and safety. We propose a novel pathway for diagnosis and therapeutics of PCNSV with the purpose of improving the diagnosis, monitoring, and prognosis of this heterogeneous disorder, setting the framework for future use of tocilizumab in this condition.

Neuroradiological signs of encephalopathy in children with autism spectrum disorders associated with genetic folate deficiency

The results of five meta‑analyzes indicate the association of autism spectrum disorders (ASD) with genetic deficiency of the folate cycle (GDFC) in children. In such cases, specific encephalopathy is formed with predominant immune‑dependent pathways of pathogenesis, the radiological signs of which are insufficiently studied.&#x0D; Objective —— to describe the typical neuroimaging signs of encephalopathy in children with GDFC suffering from ASD, and to find correlations between clinical signs, mechanisms of nervous system damage and neuroimaging data to optimize the algorithm of diagnosis, monitoring and treatment.&#x0D; Methods and subjects. The retrospective analysis of medical data of 225 children aged 2 to 9 years with GDFC, in which there were clinical manifestations of ASD (183 boys and 42 girls). The diagnosis of ASD was made by child psychiatrists according to the criteria of DSM‑IV‑TR (Diagnostic and Statistical Manual of mental disorders) and ICD‑10 (The International Statistical Classification of Diseases and Related Health Problems). Pathogenic polymorphic variants of folate cycle genes were determined by PCR with restriction. Neuroimaging was performed by MRI of the brain in conventional modes (T1‑ and T2‑weighted, FLAIR) on tomographs with a magnetic induction of 1.5 T. To study the associations between the indicators, the odds ratio (OR) and the 95 % confidence interval (95 % SI) were used.&#x0D; Results. There are 5 main groups of neuroimaging signs characteristic of leukoencephalopathy, temporal mesial sclerosis, PANS/PITANDS/PANDAS, congenital CMV neuroinfection and postnatal encephalitis, mild congenital CNS abnormalities. Neuroimaging signs are closely associated with the results of special laboratory tests that characterize the known immune‑dependent mechanisms of CNS damage, and with the emergence of relevant clinical syndromes, consistent with modern concepts of major infectious or autoimmune lesions of the nervous system in immunosuppressed patients. Laboratory‑radiological‑clinical complexes (virus‑induced temporal mesial sclerosis, autoimmune limbic encephalitis, autoimmune subcortical encephalitis, autoimmune or virus‑induced demyelinating lesions of the cerebral hemispheres and mild congenital malformations) have been identified.&#x0D; Conclusions. Encephalopathy in children with ASD associated with GDFC has a complex pathogenesis and is the result of combining a number of immune‑dependent forms of CNS damage in different ways in different patients, leading to a heterogeneous clinic‑radiological phenotype.&#x0D;

BONEs not CATs attract DOGs: Semantic context effects for picture naming in the lesioned language network

The breakdown of rapid and accurate retrieval of words is a hallmark of aphasic speech and a prime target of therapeutic intervention. Complementary, psycho- and neurolinguistic research have developed a spectrum of models, how and by which neuronal network uncompromised speakers can rely on remarkable lexical retrieval capacities. Motivated by both lines of research we invited 32 participants with a chronic left hemispheric brain lesion to name pictures in the presence of distractor words. This picture-word-interference (PWI) paradigm is widely used in psycho- and neurolinguistic research.We find that also after brain lesion categorically related words (CAT → [dog]picture) impede naming, while associatively related words (BONE → [dog]picture) ease access, when compared to unrelated distractor words. The effects largely affecting latencies in neurotypical populations, are reproduced for error rate in our participants with lesions in the language network. Unsurprisingly, overall naming abilities varied greatly across patients. Notably, however, the two effects (categorical interference / associative facilitation) differ between participants. Correlating performance with lesion patterns we find support for the notion of a divergence of brain areas affording different aspects of the task: (i) lesions in the left middle temporal gyurs (MTG) deteriorate overall naming, confirming previous work; more notably, (ii) lesions comprising the inferior frontal hub (inferior frontal gyrus, IFG) of the language-network increase the interference effect for the categorical condition; on the contrary, (iii) lesions to the mid-to-posterior temporal hub (posterior middle and superior temporal gyri, pMTG/ pSTG) increase the facilitatory effect for the associative condition on error rates.The findings can be accommodated in a neuro-linguistic framework, which localizes lexical activation but also lexical interference in posterior parts of the language network (pMTG/pITG); conversely, selection between co-activated categorically related entries is afforded by frontal language areas (IFG). While purely experimental in nature our study highlights that lesion site differentially influences specific aspects of word retrieval. Since confrontational naming is a cornerstone of aphasia rehabilitation, this may be of note when designing and evaluating novel therapeutic regimes.

Distinct cognitive components and their neural substrates underlying praxis and language deficits following left hemisphere stroke

Apraxia is characterised by multiple deficits of higher motor functions, primarily caused by left hemisphere (LH) lesions to parietal-frontal praxis networks. While previous neuropsychological and lesion studies tried to relate the various apraxic deficits to specific lesion sites, a comprehensive analysis of the different apraxia profiles and the related (impaired) motor–cognitive processes as well as their differential neural substrates in LH stroke is lacking.To reveal the cognitive mechanisms that underlie the different patterns of praxis and (related) language deficits, we applied principal component analysis (PCA) to the scores of sub-acute LH stroke patients (n = 91) in several tests of apraxia and aphasia. Voxel-based lesion-symptom mapping (VLSM) analyses were then used to investigate the neural substrates of the identified components.The PCA yielded a first component related to language functions and three components related to praxis functions, with each component associated with specific lesion patterns. Regarding praxis functions, performance in imitating arm/hand gestures was accounted for by a second component related to the left precentral gyrus and the inferior parietal lobule. Imitating finger configurations, pantomiming the use of objects related to the face, and actually using objects loaded on component 3, related to the left anterior intraparietal sulcus and angular gyrus. The last component represented the imitation of bucco-facial gestures and was linked to the basal ganglia and LH white matter tracts. The results further revealed that pantomime of (limb-related) object use depended on both the component 2 and 3, which were shared with gesture imitation and actual object use.Data support and extend the notion that apraxia represents a multi-componential syndrome comprising different (impaired) motor–cognitive processes, which dissociate – at least partially – from language processes. The distinct components might be disturbed to a varying degree following LH stroke since they are associated with specific lesion patterns within the LH.

Neural effective connectivity explains subjective fatigue in stroke.

Persistent fatigue is a major debilitating symptom in many psychiatric and neurological conditions, including stroke. Post-stroke fatigue has been linked to low corticomotor excitability. Yet, it remains elusive as to what the neuronal mechanisms are that underlie motor cortex excitability and chronic persistence of fatigue.In this cross-sectional observational study, in two experiments we examined a total of 59 non-depressed stroke survivors with minimal motoric and cognitive impairments using ‘resting-state’ MRI and single- and paired-pulse transcranial magnetic stimulation.In the first session of Experiment 1, we assessed resting motor thresholds—a typical measure of cortical excitability—by applying transcranial magnetic stimulation to the primary motor cortex (M1) and measuring motor-evoked potentials in the hand affected by stroke. In the second session, we measured their brain activity with resting-state MRI to assess effective connectivity interactions at rest. In Experiment 2 we examined effective inter-hemispheric connectivity in an independent sample of patients using paired-pulse transcranial magnetic stimulation. We also assessed the levels of non-exercise induced, persistent fatigue using Fatigue Severity Scale (FSS-7), a self-report questionnaire that has been widely applied and validated across different conditions. We used spectral dynamic causal modelling in Experiment 1 and paired-pulse transcranial magnetic stimulation in Experiment 2 to characterize how neuronal effective connectivity relates to self-reported post-stroke fatigue. In a multiple regression analysis, we used the balance in inhibitory connectivity between homologue regions in M1 as the main predictor, and have included lesioned hemisphere, resting motor threshold and levels of depression as additional predictors.Our novel index of inter-hemispheric inhibition balance was a significant predictor of post-stroke fatigue in Experiment 1 (β = 1.524, P = 7.56 × 10−5, confidence interval: 0.921 to 2.127) and in Experiment 2 (β = 0.541, P = 0.049, confidence interval: 0.002 to 1.080). In Experiment 2, depression scores and corticospinal excitability, a measure associated with subjective fatigue, also significantly accounted for variability in fatigue.We suggest that the balance in inter-hemispheric inhibitory effects between primary motor regions can explain subjective post-stroke fatigue. Findings provide novel insights into neural mechanisms that underlie persistent fatigue.

Suboccipital Transhorizontal Fissure Approach for Posterior Cranial Fossa Lesions: A Cadaveric Study and First Clinical Experience.

Surgical treatment of pathological lesions in the deep cerebellar hemisphere, cerebellopontine angle (CPA), and fourth ventricle of the posterior cranial fossa (PCF) is challenging. Conventional neurosurgical approaches to these lesions are associated with risk of various complications. Mastery of efficient fissure dissection is imperative when approaching deep-seated lesions. The horizontal fissure (HF) is the largest and deepest fissure of the cerebellum. To conduct an anatomical study and introduce a novel suboccipital trans-HF (SOTHF) approach to access lesions of the deep cerebellar hemispheres, CPA, and upper fourth ventricle of the PCF. We performed a cadaveric dissection study focusing on anatomical landmarks and surgical feasibility of the SOTHF approach then implemented it in 2 patients with a deep cerebellar hemispheric tumor. Anatomical feasibility of the SOTHF approach was demonstrated and compared with conventional approaches in the cadaveric study. Opening the suboccipital surface of the HF to create medial, intermediate, and lateral surgical corridors provided optimal viewing angles and wide access to the deep cerebellar hemispheres, CPA, and upper fourth ventricle without heavy cerebellar retraction. Sacrificing cerebellar neural structures and complex skull base techniques were not required to obtain adequate exposure. The SOTHF approach was successfully applied without complication in 2 patients with a deep cerebellar hemispheric tumor. The HF is an important cerebellar fissure that provides a gateway to deep areas of the PCF. Further studies are needed to define and expand applications of the SOTHF approach.

Effects of Galvanic Vestibular Stimulation on Visual Verticality and Standing Posture Differ Based on the Polarity of the Stimulation and Hemispheric Lesion Side in Patients With Stroke.

Introduction: There is growing evidence supporting the relationship of vertical misperception and poor balance control with asymmetrical standing posture in patients with stroke. Although the vestibular system has been shown to be responsible for vertical misperception and balance disorders, the effect of galvanic vestibular stimulation (GVS) on both vertical misperception and postural asymmetry after stroke remains elusive. The aim of this study was to investigate the effects of GVS on visual verticality and postural asymmetry after stroke and to clarify whether the effects differ depending on the polarity of the stimulation and hemispheric lesion side.Methods: We measured the subjective visual vertical (SVV) and body weight distribution on each foot in an upright stance in 24 patients with a hemispheric stroke (10 with a left hemisphere lesion and 14 with a right hemisphere lesion) and nine age-matched healthy controls. During the measurements, bipolar GVS (1.5 mA) was applied over the bilateral mastoid processes in three stimulation conditions: contralesional-anodal and ipsilesional-cathodal vestibular stimulation, ipsilesional-anodal and contralesional-cathodal vestibular stimulation, and no stimulation. To examine whether GVS modulates visual verticality and standing posture, SVV and weight-bearing in the three conditions were analyzed.Results: During no stimulation, the SVV deviated to the contralesional side in patients with a right hemisphere lesion, while more weight-bearing was observed on the ipsilesional limb than on the contralesional limb in both patient groups than in the controls. The SVV was modulated by reversing the polarity of GVS in all the groups when the cathodal stimulus side was either ipsilateral or contralateral to the lesion while the ipsilesional-cathodal vestibular stimulation reduced weight-bearing asymmetry in only the patients with a right hemisphere lesion.Conclusions: These findings demonstrate that the effects of GVS on the SVV and standing posture differ depending on the polarity of GVS and the hemispheric lesion side. Patients with a right hemisphere lesion have difficulty maintaining their preferred standing posture under visual verticality modulation evoked by GVS. The application of GVS may clarify whether the vestibular system has neural redundancy after stroke to suppress any effects of the stimulation, including modulation of the visual verticality, on balance.

Contralesional plasticity following constraint-induced movement therapy benefits outcome: contributions of the intact hemisphere to functional recovery.

Stroke is a leading cause of death and disability worldwide. A common, chronic deficit after stroke is upper limb impairment, which can be exacerbated by compensatory use of the nonparetic limb. Resulting in learned nonuse of the paretic limb, compensatory reliance on the nonparetic limb can be discouraged with constraint-induced movement therapy (CIMT). CIMT is a rehabilitative strategy that may promote functional recovery of the paretic limb in both acute and chronic stroke patients through intensive practice of the paretic limb combined with binding, or otherwise preventing activation of, the nonparetic limb during daily living exercises. The neural mechanisms that support CIMT have been described in the lesioned hemisphere, but there is a less thorough understanding of the contralesional changes that support improved functional outcome following CIMT. Using both human and non-human animal studies, the current review explores the role of the contralesional hemisphere in functional recovery of stroke as it relates to CIMT. Current findings point to a need for a better understanding of the functional significance of contralesional changes, which may be determined by lesion size, location, and severity as well stroke chronicity.

Ipsilesional Mu Rhythm Desynchronization Correlates With Improvements in Affected Hand Grip Strength and Functional Connectivity in Sensorimotor Cortices Following BCI-FES Intervention for Upper Extremity in Stroke Survivors.

Stroke is a leading cause of acquired long-term upper extremity motor disability. Current standard of care trajectories fail to deliver sufficient motor rehabilitation to stroke survivors. Recent research suggests that use of brain-computer interface (BCI) devices improves motor function in stroke survivors, regardless of stroke severity and chronicity, and may induce and/or facilitate neuroplastic changes associated with motor rehabilitation. The present sub analyses of ongoing crossover-controlled trial NCT02098265 examine first whether, during movements of the affected hand compared to rest, ipsilesional Mu rhythm desynchronization of cerebral cortical sensorimotor areas [Brodmann’s areas (BA) 1-7] is localized and tracks with changes in grip force strength. Secondly, we test the hypothesis that BCI intervention results in changes in frequency-specific directional flow of information transmission (direct path functional connectivity) in BA 1-7 by measuring changes in isolated effective coherence (iCoh) between cerebral cortical sensorimotor areas thought to relate to electrophysiological signatures of motor actions and motor learning. A sample of 16 stroke survivors with right hemisphere lesions (left hand motor impairment), received a maximum of 18–30 h of BCI intervention. Electroencephalograms were recorded during intervention sessions while outcome measures of motor function and capacity were assessed at baseline and completion of intervention. Greater desynchronization of Mu rhythm, during movements of the impaired hand compared to rest, were primarily localized to ipsilesional sensorimotor cortices (BA 1-7). In addition, increased Mu desynchronization in the ipsilesional primary motor cortex, Post vs. Pre BCI intervention, correlated significantly with improvements in hand function as assessed by grip force measurements. Moreover, the results show a significant change in the direction of causal information flow, as measured by iCoh, toward the ipsilesional motor (BA 4) and ipsilesional premotor cortices (BA 6) during BCI intervention. Significant iCoh increases from ipsilesional BA 4 to ipsilesional BA 6 were observed in both Mu [8–12 Hz] and Beta [18–26 Hz] frequency ranges. In summary, the present results are indicative of improvements in motor capacity and behavior, and they are consistent with the view that BCI-FES intervention improves functional motor capacity of the ipsilesional hemisphere and the impaired hand.

Representation of Body Orientation in Vestibular-Defective Patients Before and After Unilateral Vestibular Loss.

Introduction: The unilateral vestibular syndrome results in postural, oculomotor, perceptive, and cognitive symptoms. This study was designed to investigate the role of vestibular signals in body orientation representation, which remains poorly considered in vestibular patients.Methods: The subjective straight ahead (SSA) was investigated using a method disentangling translation and rotation components of error. Participants were required to align a rod with their body midline in the horizontal plane. Patients with right vestibular neurotomy (RVN; n =8) or left vestibular neurotomy (LVN; n = 13) or vestibular schwannoma resection were compared with 12 healthy controls. Patients were tested the day before surgery and during the recovery period, 7 days and 2 months after the surgery.Results: Before and after unilateral vestibular neurotomy, i.e., in the chronic phases, patients showed a rightward translation bias of their SSA, without rotation bias, whatever the side of the vestibular loss. However, the data show that the lower the translation error before neurotomy, the greater its increase 2 months after a total unilateral vestibular loss, therefore leading to a rightward translation of similar amplitude in the two groups of patients. In the early phase after surgery, SSA moved toward the operated side both in translation and in rotation, as typically found for biases occurring after unilateral vestibular loss, such as the subjective visual vertical (SVV) bias.Discussion and Conclusion: This study gives the first description of the immediate consequences and of the recovery time course of body orientation representation after a complete unilateral vestibular loss. The overall evolution differed according to the side of the lesion with more extensive changes over time before and after left vestibular loss. It is noteworthy that representational disturbances of self-orientation were highly unusual in the chronic stage after vestibular loss and similar to those reported after hemispheric lesions causing spatial neglect, while classical ipsilesional biases were reported in the acute stage. This study strongly supports the notion that the vestibular system plays a major role in body representation processes and more broadly in spatial cognition. From a clinical point of view, SSA appeared to be a reliable indicator for the presence of a vestibular disorder.

Ischaemic stroke caused by spontaneous unilateral carotid artery dissection in patient with connective tissue disorder

Background: Spontaneous cervical artery dissection is a major cause of ischaemic stroke in young patients. It is supposed that genetic variants associated with connective tissue disorders often lead to neurovascular complications, the management of which remains a challenge. Case presentation: A 30-year-old female was admitted to the Department of Neurology with an episode of visual disturbances, speech problems, and concomitant headache. Computed tomography angiography revealed left internal carotid artery dissection. Magnetic resonance of the brain showed cortical and subcortical acute ischaemic lesions in the left cerebral hemisphere. The patient was diagnosed with vascular Ehlers–Danlos syndrome based on the clinical course of the disease. Conservative treatment was administered with full neurological recovery. Conclusion: It is very important for clinicians to consider the coexistence of genetically determined connective tissue disorders in young patients who develop arterial dissections.