Evidence of motor injury due to damaged corticospinal tract following acute hemorrhage in the basal ganglia region

Bilateral basal ganglia hemorrhage: a systematic review of etiologies, management strategies, and clinical outcomes

Bilateral basal ganglia hemorrhages (BBGHs) represent rare accidents, with no clear standard of care currently defined. We reviewed the literature on BBGHs and analyzed the available conservative and surgical strategies. PubMed, Scopus, Web of Science, and Cochrane were searched following the PRISMA guidelines to include studies reporting patients with BBGHs. Clinical characteristics, management, and outcomes were analyzed. We included 64 studies comprising 75 patients, 25 (33%) traumatic and 50 (67%) non-traumatic. Traumatic cases affected younger patients (mean age 35 vs. 46 years, p=0.014) and males (84% vs. 71%, p=0.27) and were characterized by higher proportion of normal blood pressures at admission (66% vs. 13%, p=0.0016) compared to non-traumatic cases. Most patients were comatose at admission (56%), with a mean Glasgow Coma Scale (GCS) score of 7 and a higher proportion of comatose patients in the traumatic than in the non-traumatic group (64% vs. 52%, p=0.28). Among the traumatic group, motor vehicle accidents and falls accounted for 79% of cases. In the non-traumatic group, hemorrhage was most associated with hypertensive or ischemic (54%) and chemical (28%) etiologies. Management was predominantly conservative (83%). Outcomes were poor in 56% of patients with mean follow-up of 8 months. Good recovery was significantly higher in the traumatic than in the non-traumatic group (48% vs. 17%, p=0.019). BBGHs are rare occurrences with dismal prognoses. Standard management follows that of current intracerebral hemorrhage guidelines with supportive care and early blood pressure management. Minimally invasive surgery is promising, though substantial evidence is required to outweigh the potentially increased risks of bilateral hematoma evacuation.

Pathway-Specific Mediation Effect Between Structure, Function, and Motor Impairment After Subcortical Stroke

BACKGROUND AND OBJECTIVE

To investigate the pathway-specific correspondence between structural and functional changes resulting from focal subcortical stroke and their causal influence on clinical symptom.

METHODS

In this retrospective, cross-sectional study, we mainly focused on patients with unilateral subcortical chronic stroke with moderate-severe motor impairment assessed by Fugl-Meyer Assessment (upper extremity) and healthy controls. All participants underwent both resting-state fMRI and diffusion tensor imaging. To parse the pathway-specific structure-function covariation, we performed association analyses between the fine-grained corticospinal tracts (CSTs) originating from 6 subareas of the sensorimotor cortex and functional connectivity (FC) of the corresponding subarea, along with the refined corpus callosum (CC) sections and interhemispheric FC. A mediation analysis with FC as the mediator was used to further assess the pathway-specific effects of structural damage on motor impairment.

RESULTS

Thirty-five patients (mean age 52.7 ± 10.2 years, 27 men) and 43 healthy controls (mean age 56.2 ± 9.3 years, 21 men) were enrolled. Among the 6 CSTs, we identified 9 structurally and functionally covaried pathways, originating from the ipsilesional primary motor area (M1), dorsal premotor area (PMd), and primary somatosensory cortex (p < 0.05, corrected). FC for the bilateral M1, PMd, and ventral premotor cortex covaried with secondary degeneration of the corresponding CC sections (p < 0.05, corrected). Moreover, these covarying structures and functions were significantly correlated with the Fugl-Meyer Assessment (upper extremity) scores (p < 0.05, uncorrected). In particular, FC between the ipsilesional PMd and contralesional cerebellum (β = -0.141, p < 0.05, CI = [-0.319 to -0.015]) and interhemispheric FC of the PMd (β = 0.169, p < 0.05, CI = [0.015-0.391]) showed significant mediation effects in the prediction of motor impairment with structural damage of the CST and CC.

DISCUSSIONS

This study reveals causal influence of structural and functional pathways on motor impairment after subcortical stroke and provides a promising way to investigate pathway-specific structure-function coupling. Clinically, our findings may offer a circuit-based evidence for the PMd as a critical neuromodulation target in more impaired patients with stroke and also suggest the cerebellum as a potential target.

A Nurr1 ligand C-DIM12 attenuates brain inflammation and improves functional recovery after intracerebral hemorrhage in mice

We have previously reported that amodiaquine, a compound that binds to the ligand-binding domain of a nuclear receptor Nurr1, attenuates inflammatory responses and neurological deficits after intracerebral hemorrhage (ICH) in mice. 1,1-Bis(3'-indolyl)-1-(p-chlorophenyl)methane (C-DIM12) is another Nurr1 ligand that recognizes a domain of Nurr1 different from the ligand-binding domain. In the present study, mice were treated daily with C-DIM12 (50 or 100 mg/kg, p.o.) or amodiaquine (40 mg/kg, i.p.), or twice daily with 1400 W (20 mg/kg, i.p.), an inducible nitric oxide synthase (iNOS) inhibitor, from 3 h after ICH induction by microinjection of collagenase into the striatum. C-DIM12 improved the recovery of neurological function and prevented neuron loss in the hematoma, while suppressed activation of microglia/macrophages and expression of inflammatory mediators interleukin-6 and CC chemokine ligand 2. In addition, C-DIM12 as well as amodiaquine preserved axonal structures in the internal capsule and axonal transport function. We also found that C-DIM12 and amodiaquine suppressed the increases of iNOS mRNA expression after ICH. Moreover, 1400 W improved neurological function and prevented neuron loss, activation of microglia/macrophages and axonal transport dysfunction. These results suggest that suppression of iNOS induction contributes to several features of the therapeutic effects of Nurr1 ligands.

Association Between Anatomical Location and Hematoma Expansion in Deep Intracerebral Hemorrhage

Objective

To establish the relationship between hematoma sites of involvement and hematoma expansion (HE) in patients with deep intracerebral hemorrhage (ICH).

Methods

Eligible patients with deep ICH admitted to hospital within 6 hours of onset between 2018 and 2020 were included in this retrospective multi-center study. Individuals with secondary ICH were excluded. The volume of HE was evaluated based on admission and follow-up computed tomography scans. Associations between deep ICH sites of involvement and HE were examined using multivariable logistic regression analysis while adjusting for confounding covariates of HE.

Results

We enrolled 583 individuals from three stroke centers. Data from a final total of 460 patients were used in the analysis; of these patients, 159 (34.6%) had HE. In the crude model without adjustment, external capsule, anterior limb of the internal capsule, and posterior limb of the internal capsule (PLIC) involvement were correlated with HE. After fully adjusted models for sex, age, intraventricular hemorrhage, Glasgow Coma Scale admission score, baseline ICH volume, and time from onset to initial computed tomography, multivariable logistic regression revealed that the PLIC is a robust predictor of HE in patients with deep ICH (adjusted odds ratio = 2.73; 95% confidence interval = 1.75–4.26; p < 0.001).

Conclusion

Involvement of the posterior limb of the internal capsule in deep hemorrhage could be a promising predictor of HE.

General additive models address statistical issues in diffusion MRI: An example with clinically anxious adolescents

Statistical models employed to test for group differences in quantized diffusion-weighted MRI white matter tracts often fail to account for the large number of data points per tract in addition to the distribution, type, and interdependence of the data. To address these issues, we propose the use of Generalized Additive Models (GAMs) and supply code and examples to aid in their implementation. Specifically, using diffusion data from 73 periadolescent clinically anxious and no-psychiatric-diagnosis control participants, we tested for group tract differences and show that a GAM allows for the identification of differences within a tract while accounting for the nature of the data as well as covariates and group factors. Further, we then used these tract differences to investigate their association with performance on a memory test. When comparing our high versus low anxiety groups, we observed a positive association between the left uncinate fasciculus and memory overgeneralization for negatively valenced stimuli. This same association was not evident in the right uncinate or anterior forceps. These findings illustrate that GAMs are well-suited for modeling diffusion data while accounting for various aspects of the data, and suggest that the adoption of GAMs will be a powerful investigatory tool for diffusion-weighted analyses.

A Comparative Study of Diffusion Fiber Reconstruction Models for Pyramidal Tract Branches

Currently, comparative studies evaluating the quantification accuracy of pyramidal tracts (PT) and PT branches that were tracked based on four mainstream diffusion models are deficient. The present study aims to evaluate four mainstream models using the high-quality Human Connectome Project (HCP) dataset. Diffusion tensor imaging (DTI), diffusion spectral imaging (DSI), generalized Q-space sampling imaging (GQI), and Q-ball imaging (QBI) were used to construct the PT and PT branches in 50 healthy volunteers from the HCP. False and true PT fibers were identified based on anatomic information. One-way repeated measure analysis of variance and post hoc paired-sample t-test were performed to identify the best PT and PT branch quantification model. The number, percentage, and density of true fibers of PT obtained based on GQI and QBI were significantly larger than those based on DTI and DSI (all p < 0.0005, Bonferroni corrected), whereas false fibers yielded the opposite results (all p < 0.0005, Bonferroni corrected). More trunk branches (PT_trunk) were present in the four diffusion models compared with the upper limb (PT_Ulimb), lower limb (PT_Llimb), and cranial (PT_cranial) branches. In addition, significantly more true fibers were obtained in PT_trunk, PT_Ulimb, and PT_Llimb based on the GQI and QBI compared with DTI and DSI (all p < 0.0005, Bonferroni corrected). Finally, GQI-based group probabilistic maps showed that the four PT branches exhibited relatively unique spatial distributions. Therefore, the GQI and QBI represent better diffusion models for the PT and PT branches. The group probabilistic maps of PT branches have been shared with the public to facilitate more precise studies on the plasticity of and the damage to the motor pathway.