Hemisphere Lesions Research Articles

FRI324 Pituitary Macroadenoma With Carcinomatous Transformation And Multiple Cranial Masses And Spinal Leptomeningeal Carcinomatosis: A Case Report

Abstract Disclosure: C. Cristancho: None. G. Szabo: None. Background: Aggressive pituitary tumors are invasive tumors not responding to standard therapies and presenting with multiple local recurrences; if metastases occur, the tumors are defined as pituitary carcinoma (PC) Clinical Case: 51- year-old Hispanic woman with history of pituitary macroadenoma diagnosed at the age of 41, when presented with weight gain and decrease in visual acuity. Per records initial Brain MRI reported hyperintense sellar lesion of 2.1x2.3x2.6 cm with supra-sella extension and shift of optic chiasm. Patient had 4 pituitary surgeries between 2014-2018 due to growth and had radiation and Temozolomide between 2018-2020. Pathology was diffusely positive for ACTH, PRL, and Ki-67 was 10-20%, P 55 positive staining was 25-30%. As a result from pituitary surgeries patient developed central hypothyroidism, and central AI. Subsequent mornings cortisol were nl between 16-18. No UFC or LNSC were available. MEN1 negative. Brain MRIs done between 2019 and 2020 showed stable 13x8 mm residual pituitary mass with postoperative changes. Patient denied history of diabetes, fragility fractures, HTN, DVTs. She had regular menstrual periods until age of 42. Had left adrenal mass resection in 2019 with benign pathology results. During her initial endocrinology visit her ROS was positive for lower back pain and mild proximal muscle weakness. Patient denied visual changes, headaches, skin changes, polydipsia or polyuria. Physical exam was remarkable for small buffalo hump, and 5-/5 proximal muscle weakness. Negative for moon face, purple striae, acanthosis nigricans, hirsutism, acne. Initial tests were consistent with ACTH-dependent CS: elevated cortisol PM: 18.2 (n <10ug/dL) and LNSC 0.58 and 0.64 mcg/dl (n <0.09), 24-hr UFC 264 (n <50 mcg/dl), abnormal ACTH 150 (n <50 pg/ml).Brain MRI revealing extra-axial mass of 1.6 x1.1 cm overlying posterior aspect of right cerebellar hemisphere and focal lesion in left prepontine cistern of 0.8 cm. Leptomeningeal Enhancement. No sellar mass. Spine MRI showed scattered nodules lining the cord throughout the cervical and upper thoracic spine concerning for metastatic disease. Right cerebellar mass biopsy positive for metastatic pituitary neuroendocrine tumor corticotroph cell subtype, ACTH, chromogranin A, synaptophysin positive; PRL, TSH, GnRH, alpha subunit staining was negative; Ki-67 of 2%. Temozolomide, Capecitabin, and Ketoconazole 200 mg TID were started. Subsequent LNSC <0.03 and <0.03 mcg/dl, UFC at 3 different times were 12.8, 11.2 and 8.1 mcg/dl showing rapid decrease of cortisol levels in a 4-week period. A block-replace approach was decided with Dexamethasone 1 mg daily and a lower dose of Ketoconazole 200 mg BID. Patient reports no side effects. Presentation: Friday, June 16, 2023

Factors Associated with Post-Non Hemorrhagic Stroke Depression: a cross-sectional study

Background: Post-stroke patient depression can result in delays in stroke recovery and healing. The degree of severity of stroke will cause neurological deficits which can become stressors that will affect individual coping mechanisms.Objective: This research aims to analyze factors associated with non-hemorrhagic post-stroke depression.Methods: Analytical observational with a cross-sectional approach. The research was conducted at the Neurology Clinic of RSUD dr. R. Goeteng Taroenadibrata Purbalingga. The population is 435 post-stroke non-hemorrhagic patients. The sample is 104 respondents with the sampling technique used consecutive sampling. The instruments used were the Brief COPE, NIHSS, and PHQ-9. Bivariate analysis used the Kendall-Tau correlation test.Results: The majority of respondents were elderly, male, primary school education level/equivalent, married, live with husband/wife and children, left hemisphere lesion location, had stroke duration 2 years, did not experience recurrent strokes, hypertension, had problem-focused coping and mild stroke severity with varying degrees of depression. Age, gender, marital status, living together, location of the lesion, duration of stroke, stroke frequency, comorbidities and coping mechanisms were not significantly related (p0.05) while education level and stroke severity was significantly associated with post-stroke depression (p0,05).Conclusions: There is a significant relationship between education level and severity of stroke with post-stroke depression. Nurses can also motivate patients to always take medication regularly, increase patient knowledge about stroke and depression, or implement non-pharmacological therapy such as Range of Motion (ROM) so that they can help reduce the severity of a stroke and prevent or reduce the occurrence of depression after non-hemorrhagic stroke.

Machine learning-based prediction of post-stroke cognitive status using electroencephalography-derived brain network attributes.

More than half of patients with acute ischemic stroke develop post-stroke cognitive impairment (PSCI), a significant barrier to future neurological recovery. Thus, predicting cognitive trajectories post-AIS is crucial. Our primary objective is to determine whether brain network properties from electroencephalography (EEG) can predict post-stroke cognitive function using machine learning approach. We enrolled consecutive stroke patients who underwent both EEG during the acute stroke phase and cognitive assessments 3 months post-stroke. We preprocessed acute stroke EEG data to eliminate low-quality epochs, then performed independent component analysis and quantified network characteristics using iSyncBrain®. Cognitive function was evaluated using the Montreal cognitive assessment (MoCA). We initially categorized participants based on the lateralization of their lesions and then developed machine learning models to predict cognitive status in the left and right hemisphere lesion groups. Eighty-seven patients were included, and the accuracy of lesion laterality prediction using EEG attributes was 97.0%. In the left hemispheric lesion group, the network attributes of the theta band were significantly correlated with MoCA scores, and higher global efficiency, clustering coefficient, and lower characteristic path length were associated with higher MoCA scores. Most features related to cognitive scores were selected from the frontal lobe. The predictive powers (R-squared) were 0.76 and 0.65 for the left and right stroke groups, respectively. Estimating EEG-based network properties in the acute phase of ischemic stroke through a machine learning model has a potential to predict cognitive outcomes after ischemic stroke.

Is There a Role of Inferior Frontal Cortex in Motor Timing? A Study of Paced Finger Tapping in Patients with Non-Fluent Aphasia.

The aim of the present study was to investigate the deficits in timing reproduction in individuals with non-fluent aphasia after a left hemisphere lesion including the inferior frontal gyrus, in which Broca's region is traditionally localised. Eighteen stroke patients with non-fluent aphasia and twenty-two healthy controls were recruited. We used a finger-tapping Test, which consisted of the synchronisation and the continuation phase with three fixed intervals (450 ms, 650 ms and 850 ms). Participants firstly had to tap simultaneously with the device's auditory stimuli (clips) (synchronisation phase) and then continue their tapping in the same pace when the stimuli were absent (continuation phase). Patients with aphasia demonstrated less accuracy and greater variability during reproduction in both phases, compared to healthy participants. More specifically, in the continuation phase, individuals with aphasia reproduced longer intervals than the targets, whereas healthy participants displayed accelerated responses. Moreover, patients' timing variability was greater in the absence of the auditory stimuli. This could possibly be attributed to deficient mental representation of intervals and not experiencing motor difficulties (due to left hemisphere stroke), as the two groups did not differ in tapping reproduction with either hand. Given that previous findings suggest a potential link between the IFG, timing and working memory, we argue that patients' extra-linguistic cognitive impairments should be accounted for, as possible contributing factors to timing disturbances.

Neurophysiological biomarkers of motor improvement from Constraint-Induced Movement Therapy and Robot-Assisted Therapy in participants with stroke.

The mechanism of stroke recovery is related to the reorganization of cerebral activity that can be enhanced by rehabilitation therapy. Two well established treatments are Robot-Assisted Therapy (RT) and Constraint-Induced Movement Therapy (CIMT), however, it is unknown whether there is a difference in the neuroplastic changes induced by these therapies, and if the modifications are related to motor improvement. Therefore, this study aims to identify neurophysiological biomarkers related to motor improvement of participants with chronic stroke that received RT or CIMT, and to test whether there is a difference in neuronal changes induced by these two therapies. This study included participants with chronic stroke that took part in a pilot experiment to compare CIMT vs. RT. Neurophysiological evaluations were performed with electroencephalography (EEG) and transcranial magnetic stimulation (TMS), pre and post rehabilitation therapy. Motor function was measured by the Wolf Motor Function Test (WMFT) and Fugl-Meyer Assessment Upper Limb (FMA-UL). Twenty-seven participants with chronic stroke completed the present study [mean age of 58.8 years (SD ± 13.6), mean time since stroke of 18.2 months (SD ± 9.6)]. We found that changes in motor threshold (MT) and motor evoked potential (MEP) in the lesioned hemisphere have a positive and negative correlation with WMFT improvement, respectively. The absolute change in alpha peak in the unlesioned hemisphere and the absolute change of the alpha ratio (unlesioned/lesioned hemisphere) is negatively correlated with WMFT improvement. The decrease of EEG power ratio (increase in the lesioned hemisphere and decrease in the unlesioned hemisphere) for high alpha bandwidths is correlated with better improvement in WMFT. The variable "type of treatment (RT or CIMT)" was not significant in the models. Our results suggest that distinct treatments (RT and CIMT) have similar neuroplastic mechanisms of recovery. Moreover, motor improvements in participants with chronic stroke are related to decreases of cortical excitability in the lesioned hemisphere measured with TMS. Furthermore, the balance of both EEG power and EEG alpha peak frequency in the lesioned hemisphere is related to motor improvement.

Prevalence and factors influencing cognitive impairment among the older adult stroke survivors: a cross-sectional study.

Cognitive impairment as a complication in post-stroke patients has high prevalence throughout the world. However, few studies have focused on the older adult stroke survivors and explored their prevalence and factors of post-stroke cognitive impairment (PSCI). The study aims to evaluate the cognitive status of stroke patients in Hunan Province, China and to determine the potential risk factors associated with PSCI in order to identify the older adult population in advance and promote healthy aging. This cross-sectional study was carried out from August to December, 2021. A total of 520 stroke survivors from 6 tertiary hospitals were randomly selected. The information was collected using the general questionnaire, the Barthel Index Rating Scale and the Mini-mental State Examination (MMSE). Analysis was based on descriptive statistics, chi-square test and the significant variables were included in multivariate logistic regression. The reporting of this cross-sectional study followed the STROBE checklist. A total of 195 older adults (40.37%) were screened for cognitive impairment based on the results of the MMSE score. Patients in the PSCI group had a higher proportion of individuals aged 70 or older (35.90% vs. 24.65%, p<0.001). The potential risk factors for post-stroke cognitive impairment in older adults were being aged between 70 and 79 years old (OR = 3.973, 95% CI, 2.346-6.729, p<0.001), being aged 80 years or older (OR = 3.590, 95% CI, 1.373-9.387, p = 0.009), having a low level of education (OR = 9.183, 95% CI, 5.341-15.789, p<0.001), having hypertension (OR = 1.756, 95% CI, 1.121-2.753, p = 0.014), and having a dominant hemisphere lesion (OR = 1.880, 95% CI, 1.193-2.962, p<0.001). The prevalence of PSCI was high among Chinese older adults, particularly those aged 80 years or older. The factors identified in our study could assist in the early identification of older adults at risk, develop personalized management plans, and promote healthy aging.

P01.01.A THE IMPACT OF BRAIN LESIONS ON HEALTH-RELATED QUALITY OF LIFE IN PATIENTS WITH WHO CNS GRADE 3 OR 4 GLIOMA: A LESION-FUNCTION AND RESTING-STATE FMRI ANALYSIS

Abstract BACKGROUND In glioma patients, tumor development and multimodality therapy are associated with changes in health-related quality of life (HRQoL). It is largely unknown how different types and locations of tumor- and treatment-related brain lesions, as well as their relationship to white matter tracts and functional brain networks, affect HRQoL. MATERIAL AND METHODS In 121 patients with pretreated gliomas of WHO CNS grades 3 or 4, structural MRI, O-(2-[18F]fluoroethyl)-L-tyrosine (FET) PET, resting-state functional MRI (rs-fMRI) and self-reported HRQoL questionnaires (EORTC QLQ-C30/BN20) were obtained. Resection cavities, T1-enhancing lesions, T2/FLAIR hyperintensities, and lesions with pathologically increased FET uptake were delineated. Effects of tumor lateralization, involvement of white matter tracts or resting-state network nodes by different types of lesions and within-network rs-fMRI connectivity were analyzed in terms of their interaction with HRQoL scores. RESULTS Right hemisphere gliomas were associated with significantly less favorable outcomes in physical, role, emotional and social functioning, compared with left-sided tumors. Most functional HRQoL scores correlated significantly with right-sided white-matter tracts involvement by T2/FLAIR hyperintensities and with loss of within-network functional connectivity of right-sided nodes. Tumors of the left hemisphere caused significantly more communication deficits. CONCLUSION In pretreated high-grade gliomas, right hemisphere lesions are associated with reduced HRQoL scores in most functional domains except communication ability, compared to tumors of the left hemisphere. These relationships are mainly observed for T2/FLAIR lesions involving structural and functional networks in the right hemisphere. The data suggest that sparing the right hemisphere from treatment-related tissue damage may improve HRQoL in glioma patients.

Ocimum sanctum Alters the Lipid Landscape of the Brain Cortex and Plasma to Ameliorate the Effect of Photothrombotic Stroke in a Mouse Model.

Stroke-like injuries in the brain result in not only cell death at the site of the injury but also other detrimental structural and molecular changes in regions around the stroke. A stroke-induced alteration in the lipid profile interferes with neuronal functions such as neurotransmission. Preventing these unfavorable changes is important for recovery. Ocimum sanctum (Tulsi extract) is known to have anti-inflammatory and neuroprotective properties. It is possible that Tulsi imparts a neuroprotective effect through the lipophilic transfer of active ingredients into the brain. Hence, we examined alterations in the lipid profile in the cerebral cortex as well as the plasma of mice with a photothrombotic-ischemic-stroke-like injury following the administration of a Tulsi extract. It is also possible that the lipids present in the Tulsi extract could contribute to the lipophilic transfer of active ingredients into the brain. Therefore, to identify the major lipid species in the Tulsi extract, we performed metabolomic and untargeted lipidomic analyses on the Tulsi extract. The presence of 39 molecular lipid species was detected in the Tulsi extract. We then examined the effect of a treatment using the Tulsi extract on the untargeted lipidomic profile of the brain and plasma following photothrombotic ischemic stroke in a mouse model. Mice of the C57Bl/6j strain, aged 2-3 months, were randomly divided into four groups: (i) Sham, (ii) Lesion, (iii) Lesion plus Tulsi, and (iv) Lesion plus Ibuprofen. The cerebral cortex of the lesioned hemisphere of the brain and plasma samples were collected for untargeted lipidomic profiling using a Q-Exactive Mass Spectrometer. Our results documented significant alterations in major lipid groups, including PE, PC, neutral glycerolipids, PS, and P-glycerol, in the brain and plasma samples from the photothrombotic stroke mice following their treatment with Tulsi. Upon further comparison between the different study groups of mice, levels of MGDG (36:4), which may assist in recovery, were found to be increased in the brain cortexes of the mice treated with Tulsi when compared to the other groups (p < 0.05). Lipid species such as PS, PE, LPG, and PI were commonly altered in the Sham and Lesion plus Tulsi groups. The brain samples from the Sham group were specifically enriched in many species of glycerol lipids and had reduced PE species, while their plasma samples showed altered PE and PS species when compared to the Lesion group. LPC (16:1) was found in the Tulsi extract and was significantly increased in the brains of the PTL-plus-Tulsi-treated group. Our results suggest that the neuroprotective effect of Tulsi on cerebral ischemia may be partially associated with its ability to regulate brain and plasma lipids, and these results may help provide critical insights into therapeutic options for cerebral ischemia or brain lesions.

Accuracy Comparison between Frameless Biopsy and Frame-Based Biopsy: A Retrospective Study of a Case Series

Abstract Objective To compare the efficacy and safety of frameless and frame-based techniques for biopsies of intracranial lesions in an exclusive assistance service at a public health center in Brazil (SUS). Method A review of 65 medical records of patients with brain lesions who underwent a frame-based or frameless biopsy from September 2017 to July 2019 was performed. Results Among the 65 patients who underwent biopsy, 42 were male, and 23 were female. The mean age was 53.1 years. Most patients (49; 75.4%) presented hemispheric lesions, and, of these, 27 were in the frontal lobe (41,5%). The diagnostic rate was 78.5% (51 of 65 patients), and glial neoplasia was the most common diagnosis. In addition to glial neoplasia, a wide range of pathologies were diagnosed, such as toxoplasmosis, metastasis, lymphoma, inflammatory lesions, and abscesses. Among the 14 patients (21.5%) with inconclusive results, 8 had gliosis without neoplasia (12.3%), 4 had necrosis (6.1%), and 2 had insufficient samples (3%).The morbidity rate was 9.2%, with 4 cases of hemorrhage, 1 case of infection, and 1 case of worsening of neurological deficits. The mortality rate was 6.1% and occurred in all cases with hemorrhage.There were no significant differences in the diagnosis or complication (morbidity and mortality) rates between the frame-based and frameless groups. Conclusion The frame-based and frameless techniques for stereotactic biopsy present similar efficacy and safety.

Neuroanatomy of post-stroke depression: the association between symptom clusters and lesion location.

Post-stroke depression affects about 30% of stroke patients and often hampers functional recovery. The diagnosis of depression encompasses heterogeneous symptoms at emotional, motivational, cognitive, behavioural or somatic levels. Evidence indicates that depression is caused by disruption of bio-aminergic fibre tracts between prefrontal and limbic or striatal brain regions comprising different functional networks. Voxel-based lesion-symptom mapping studies reported discrepant findings regarding the association between infarct locations and depression. Inconsistencies may be due to the usage of sum scores, thereby mixing different symptoms of depression. In this cross-sectional study, we used multivariate support vector regression for lesion-symptom mapping to identify regions significantly involved in distinct depressive symptom domains and global depression. MRI lesion data were included from 200 patients with acute first-ever ischaemic stroke (mean 0.9 ± 1.5 days of post-stroke). The Montgomery-Åsberg Depression Rating interview assessed depression severity in five symptom domains encompassing motivational, emotional and cognitive symptoms deficits, anxiety and somatic symptoms and was examined 8.4 days of post-stroke (±4.3). We found that global depression severity, irrespective of individual symptom domains, was primarily linked to right hemispheric lesions in the dorsolateral prefrontal cortex and inferior frontal gyrus. In contrast, when considering distinct symptom domains individually, the analyses yielded much more sensitive results in regions where the correlations with the global depression score yielded no effects. Accordingly, motivational deficits were associated with lesions in orbitofrontal cortex, dorsolateral prefrontal cortex, pre- and post-central gyri and basal ganglia, including putamen and pallidum. Lesions affecting the dorsal thalamus, anterior insula and somatosensory cortex were significantly associated with emotional symptoms such as sadness. Damage to the dorsolateral prefrontal cortex was associated with concentration deficits, cognitive symptoms of guilt and self-reproach. Furthermore, somatic symptoms, including loss of appetite and sleep disturbances, were linked to the insula, parietal operculum and amygdala lesions. Likewise, anxiety was associated with lesions impacting the central operculum, insula and inferior frontal gyrus. Interestingly, symptoms of anxiety were exclusively left hemispheric, whereas the lesion-symptom associations of the other domains were lateralized to the right hemisphere. In conclusion, this large-scale study shows that in acute stroke patients, differential post-stroke depression symptom domains are associated with specific structural correlates. Our findings extend existing concepts on the neural underpinnings of depressive symptoms, indicating that differential lesion patterns lead to distinct depressive symptoms in the first weeks of post-stroke. These findings may facilitate the development of personalized treatments to improve post-stroke rehabilitation.

The Kinetics of Transtentorial Brain Herniation: Kernohan-Woltman Notch Phenomenon Revisited.

To critically review recent literature in understanding the pathological consequences of transtentorial brain herniation resulting from unilateral expanding supratentorial mass lesions. Modern neuroimaging assists in understanding the consequences of transtentorial brain herniation with the development of the Kernohan-Woltman notch phenomenon. MRI studies in post-operative patients undergoing craniotomy and removal of expanding unilateral hemispheric mass lesions (usually an extradural or subdural hematoma) have shown striking findings in the contralateral crus cerebri suggestive of damage as a result of impact against the free margin of the opposite tentorium as suggested by Kernohan and Woltman nearly a century back in autopsy studies. MR changes include T1 hypointensity, T2 and fluid-attenuated inversion recovery (FLAIR) hyperintensity, DW1 hyperintensity with restriction of diffusion, presence of hypointensity in GRE sequences and evidence of axonal damage in the corticospinal tracts in the cerebral peduncle in diffusion tensor imaging and MR tractography. The pathological basis of such changes may be variable or a combination of several pathological processes, which may all be related to the impact/compression of the contralateral crus with the tentorial margin. These include contusion, compression, demyelination, and perhaps most importantly microvascular damage including microbleeds. The role of uncal herniation is debatable. It appears that as a result of massive lateral shift in the supratentorial compartment, there is a transient forceful impact of the opposite cerebral peduncle against the rigid tentorial border to induce one or more of the abovementioned phenomena to explain the imaging findings. The limitation of these studies is that most of them have been done in the post-operative periods and surgical manipulations can surely alter anatomical relationships between intracranial structures. The exact sequence of events happening intracranially in the face of rapidly expanding supratentorial mass lesions is largely unknown. Even with rapid progress in neuroimaging, documentation of such changes during life are difficult, principally for logistic reasons. Consequently, the very truth of the much taught about phenomenon of uncal herniation and the resultant Kernohan-Woltman notch phenomenon and the false localizing sign of unilateral motor weakness and contralateral pupillary dilation have been questioned. Animal experimentation and autopsy studies have not contributed much in our understanding of the actual process happening intracranially in such an emergent situation. The midbrain undoubtedly is the key structure bearing the brunt of the effect of brain shift which is more lateral than downward in cases with unilateral expanding lesions. Structural changes in the cerebral peduncles have now been visualized with modern neuroimaging. These alterations may result from the interplay of one or more factors which include compression, contusion, demyelination, and perhaps most importantly microvascular ischemia and hemorrhage resulting from a forceful yet transient impact of the cerebral peduncle with the tough tentorial margin. The last mentioned hypothesis would be in conformity with Kernohan and Woltman's concept of elastic deformation of the midbrain. In the present article an attempt is made to provide a historical account of the changing concepts in relation to brain herniation as systematically and chronologically as possible, and then, critically review recent neuroimaging observations with a view to hypothesize on the sequence of events during transtentorial brain herniation.

Impairments of the ipsilesional upper-extremity in the first 6-months post-stroke

BackgroundIpsilesional motor impairments of the arm are common after stroke. Previous studies have suggested that severity of contralesional arm impairment and/or hemisphere of lesion may predict the severity of ipsilesional arm impairments. Historically, these impairments have been assessed using clinical scales, which are less sensitive than robot-based measures of sensorimotor performance. Therefore, the objective of this study was to characterize progression of ipsilesional arm motor impairments using a robot-based assessment of motor function over the first 6-months post-stroke and quantify their relationship to (1) contralesional arm impairment severity and (2) stroke-lesioned hemisphere.MethodsA total of 106 participants with first-time, unilateral stroke completed a unilateral assessment of arm motor impairment (visually guided reaching task) using the Kinarm Exoskeleton. Participants completed the assessment along with a battery of clinical measures with both ipsilesional and contralesional arms at 1-, 6-, 12-, and 26-weeks post-stroke.ResultsRobotic assessment of arm motor function revealed a higher incidence of ipsilesional arm impairment than clinical measures immediately post-stroke. The incidence of ipsilesional arm impairments decreased from 47 to 14% across the study period. Kolmogorov–Smirnov tests revealed that ipsilesional arm impairment severity, as measured by our task, was not related to which hemisphere was lesioned. The severity of ipsilesional arm impairments was variable but displayed moderate significant relationships to contralesional arm impairment severity with some robot-based parameters.ConclusionsIpsilesional arm impairments were variable. They displayed relationships of varying strength with contralesional impairments and were not well predicted by lesioned hemisphere. With standard clinical care, 86% of ipsilesional impairments recovered by 6-months post-stroke.

The need for hemispheric separation in pairwise structural disconnection studies.

The development of new approaches indirectly measuring the structural disconnectome has recently led to an increase in studies investigating pairwise structural disconnections following brain damage. Previous studies jointly analyzed patients with left hemispheric and patients with right hemispheric lesions when investigating a behavior of interest. An alternative approach would be to perform analyses separated by hemisphere, which has been applied in only a minority of studies to date. The present simulation study investigated whether joint or separate analyses (or both equally) are appropriate to reveal the ground truth disconnections. In fact, both approaches resulted in very different patterns of disconnection. In contrast to analyses separated by hemisphere, joint analyses introduced a bias to the disadvantage of intra-hemispheric disconnections. Intra-hemispheric disconnections were statistically underpowered in the joint analysis and thus surpassed the significance threshold with more difficulty compared to inter-hemispheric disconnections. This statistical imbalance was also shown by a greater number of significant inter-hemispheric than significant intra-hemispheric disconnections. This bias from joint analyses is based on mechanisms similar to those underlying the "partial injury problem." We therefore conclude that pairwise structural disconnections in patients with unilateral left hemispheric and with unilateral right hemispheric lesions exhibiting a specific behavior (or disorder) of interest should be studied separately by hemisphere rather than in a joint analysis.

Intraoperative Neuromonitoring of the Visual Pathway in Asleep Neuro-Oncology Surgery.

Brain tumour surgery in visual eloquent areas poses significant challenges to neurosurgeons and has reported inconsistent results. This is a single-centre prospective cohort study of patients admitted for asleep surgery of intra-axial lesions in visual eloquent areas. Demographic and clinical information, data from tractography and visual evoked potentials (VEPs) monitoring were recorded and correlated with visual outcomes. Thirty-nine patients were included (20 females, 19 males; mean age 52.51 ± 14.08 years). Diffuse intrinsic glioma was noted in 61.54% of patients. There was even distribution between the temporal, occipital and parietal lobes, while 55.26% were right hemispheric lesions. Postoperatively, 74.4% remained stable in terms of visual function, 23.1% deteriorated and 2.6% improved. The tumour infiltration of the optic radiation on tractography was significantly related to the visual field deficit after surgery (p = 0.016). Higher N75 (p = 0.036) and P100 (p = 0.023) amplitudes at closure on direct cortical VEP recordings were associated with no new postoperative visual deficit. A threshold of 40% deterioration of the N75 (p = 0.035) and P100 (p = 0.020) amplitudes correlated with a risk of visual field deterioration. To conclude, direct cortical VEP recordings demonstrated a strong correlation with visual outcomes, contrary to transcranial recordings. Invasion of the optic radiation is related to worse visual field outcomes.

Early Onset of Rapid Lesion Growth in an Acute Subdural Hematoma Model in Rats

Acute subdural hematoma (ASDH) leads to the highest mortality rates of all head injuries with secondary brain damage playing a pivotal role in terms of morbidity and mortality. In patients with ASDH, a delay in surgery leads to disproportional mortality. The benefit of (very) early therapy is therefore, a target of ongoing research. As the process of delayed brain damage in ASDH has not yet been described, this study therefore aimed to examine secondary lesion growth in an experimental rat model of ASDH to define the ideal timing for testing potential neuroprotective therapies. Cerebral blood flow was monitored during ASDH induction with 300μl of autologous blood. Lesion growth was characterized using Hematoxylin-Eosin- , Cresyl-Violet-, and Fluoro-Jade B-staining for early signs of neuronal degeneration. Histological evaluations were performed between 15minutes and 24hours after ASDH. There was a significant reduction of cerebral blood flow after ASDH. Fluoro-Jade B-positive cells were visible 15minutes after ASDH in the lesioned hemisphere. Nonlinear growth of lesion volume from 3.7±0.4mm3 to 17.5±0.6mm3 was observed at 24hours in Hematoxylin-Eosin-staining. The most damage develops between 15minutes and 1hour and again between 2 and 6hours after ASDH. The time course of lesion growth supports the approach of early surgery for patients. It furthermore constitutes a basis for further ASDH research with more clearly defined time windows for therapy in animal models.

Robot-assisted transcerebellar stereotactic approach to the posterior fossa in pediatric patients: a technical note.

During the last decade, there has been renewed interest in stereotactic approaches to diffuse intrinsic pontine gliomas (DIPGs) in children, due to the development of new concepts in molecular biology and management, and subsequent need for tissue sampling. Stereotactic frame-based and robot-assisted techniques are associated with reduced target error and have been incorporated into standard practice at our institution. Four children (age 2-7years) underwent a robot-assisted frame-based transcerebellar approach using the Leksell G frame coupled with Renishaw's neuromate® stereotactic robot. The procedures included 3 biopsies (two brainstem tumors and one cerebellar hemispheric lesion) and 1 depth electrode implantation into a low-grade tumor remnant (ganglioglioma) of the middle cerebellar peduncle causing drug-resistant epilepsy in a young girl. Targeting was based on MRI, and in one case, 18F-FET-PET was coregistered to MRI to improve sampling accuracy. The frame was applied 180° rotated compared to standard orientation, and patients were positioned prone during surgery and stereotactic preoperative CT scan. Postoperative CT scan ruled out complications and was coregistered to preoperative MRI to check the target accuracy. No complications occurred, and targeting was accurate in all cases. All tissue samplings provided proper histology; depth electrode EEG exploration was diagnostic and led subsequent resective surgery. According to our experience, the transcerebellar frame-based robotic stereotactic approach to the cerebellum and the brainstem is feasible, safe, and effective even in young children.

Association of Circumscribed Subcortical Gray and White Matter Lesions With Apraxic Deficits in Patients With Left Hemisphere Stroke.

Apraxia is commonly attributed to left hemisphere (LH) lesions of the cortical fronto-temporo-parietal praxis networks or white matter lesions causing disconnections between cortical nodes. By contrast, the contribution of lesions to the subcortical gray matter, that is, basal ganglia or thalamus, to apraxic deficits remains controversial. Here, we investigate whether damage to these subcortical gray matter structures (i.e., caudate nucleus, putamen, globus pallidus, and thalamus) or the adjacent white matter tracts was associated with apraxic deficits. We identified patients with distinct subcortical lesions with and without apraxia from a large retrospective sample of subacute LH ischemic stroke patients (n = 194). To test which subcortical structures (caudate nucleus, putamen, globus pallidus, thalamus, and adjacent white matter tracts), when lesioned, contributed to apraxic deficits, we statistically compared the proportion of lesioned voxels within subcortical gray and white matter structures between the apraxic and nonapraxic patients. Of the 194 stroke patients screened, 39 (median age = 65 years, range 30-82 years; median time poststroke at the apraxia assessment = 7 days, range 1-44 days) had lesions confined to subcortical regions (gray and white matter). Eleven patients showed apraxic deficits when imitating gestures or pantomiming object use. Region-wise statistical lesion comparison (controlled for lesion size) revealed a more significant proportion of damage ('lesion load') in the caudate nucleus in apraxic stroke patients (mean difference = 6.9%, 95% CI 0.4-13.3, p = 0.038, η p 2 = 0.11). By contrast, apraxic patients had lower lesion load in the globus pallidus (mean difference = 9.9%, 95% CI 0.1-19.8, p = 0.048, η p 2 = 0.10), whereas the lesion load in other subcortical structures (putamen, thalamus, and adjacent white matter tracts) did not differ significantly between the apraxic and nonapraxic patients. These findings provide new insights into the subcortical anatomy of apraxia after LH stroke, suggesting a specific contribution of caudate nucleus lesions to apraxic deficits.

Novel personalized treatment strategy for patients with chronic stroke with severe upper-extremity impairment: The first patient of the AVANCER trial

Around 25% of patients who have had a stroke suffer from severe upper-limb impairment and lack effective rehabilitation strategies. The AVANCER proof-of-concept clinical trial (NCT04448483) tackles this issue through an intensive and personalized-dosage cumulative intervention that combines multiple non-invasive neurotechnologies. The therapy consists of two sequential interventions, lasting until the patient shows no further motor improvement, for a minimum of 11 sessions each. The first phase involves a brain-computer interface governing an exoskeleton and multi-channel functional electrical stimulation enabling full upper-limb movements. The second phase adds anodal transcranial direct current stimulation of the motor cortex of the lesioned hemisphere. Clinical, electrophysiological, and neuroimaging examinations are performed before, between, and after the two interventions (T0, T1, and T2). This case report presents the results from the first patient of the study. The primary outcome (i.e., 4-point improvement in the Fugl-Meyer assessment of the upper extremity) was met in the first patient, with an increase from 6 to 11 points between T0 and T2. This improvement was paralleled by changes in motor-network structure and function. Resting-state and transcranial magnetic stimulation-evoked electroencephalography revealed brain functional changes, and magnetic resonance imaging (MRI) measures detected structural and task-related functional changes. These first results are promising, pointing to feasibility, safety, and potential efficacy of this personalized approach acting synergistically on the nervous and musculoskeletal systems. Integrating multi-modal data may provide valuable insights into underlying mechanisms driving the improvements and providing predictive information regarding treatment response and outcomes. This work was funded by the Wyss-Center for Bio and Neuro Engineering (WCP-030), the Defitech Foundation, PHRT-#2017-205, ERA-NET-NEURON (Discover), and SNSF (320030L_197899, NiBS-iCog).

Top-down and bottom-up stimulation techniques combined with action observation treatment in stroke rehabilitation: a perspective.

Stroke is a central nervous system disease that causes structural lesions and functional impairments of the brain, resulting in varying types, and degrees of dysfunction. The bimodal balance-recovery model (interhemispheric competition model and vicariation model) has been proposed as the mechanism of functional recovery after a stroke. We analyzed how combinations of motor observation treatment approaches, transcranial electrical (TES) or magnetic (TMS) stimulation and peripheral electrical (PES) or magnetic (PMS) stimulation techniques can be taken as accessorial physical therapy methods on symptom reduction of stroke patients. We suggest that top-down and bottom-up stimulation techniques combined with action observation treatment synergistically might develop into valuable physical therapy strategies in neurorehabilitation after stroke. We explored how TES or TMS intervention over the contralesional hemisphere or the lesioned hemisphere combined with PES or PMS of the paretic limbs during motor observation followed by action execution have super-additive effects to potentiate the effect of conventional treatment in stroke patients. The proposed paradigm could be an innovative and adjunctive approach to potentiate the effect of conventional rehabilitation treatment, especially for those patients with severe motor deficits.

The neuropsychology and neuroanatomy of reduplicative paramnesia

Reduplicative paramnesia refers to the delusional belief that there are identical places in different locations. In this case–control study we investigated the clinical, phenomenological, neuropsychological and neuroanatomical data of eleven patients with reduplicative paramnesia and compared them against a control group of eleven patients with severe spatial disorientation without signs of reduplicative paramnesia.We show that most patients with reduplicative paramnesia report that a current place is reduplicated and/or relocated to an other familiar place. Patients with reduplicative paramnesia show a higher prevalence of deficits in the executive functions compared to the control patients, while mnestic and visuo-spatial deficits were both frequent in patients with reduplicative paramnesia and the control group. Patients with reduplicative paramnesia mostly suffer from right hemispheric lesions with a maximal overlap in the dorsolateral prefrontal cortex. Using lesion network mapping we show that lesions causing reduplicative paramnesia are connected to bilateral anterior insula and the right cingulate cortex.We argue that patients with reduplicative paramnesia fail to integrate the actual context with visuo-spatial memories and personal relevant emotional information due to a disruption of the neural network within the anterior temporal lobe, the cingulate cortex and the anterior insula. Also patients with reduplicative paramnesia are not able to resolve this conflict due to the lesion of the dorsolateral prefrontal cortex and executive dysfunction.