The Relationship between Cerebral White Matter Integrity and Cognitive Function in Mild Stroke with Basal Ganglia Region Infarcts

Brain structural-functional coupling mechanism in mild subcortical stroke and its relationship with cognition

OBJECTIVES

Stroke can lead to significant restructuring of brain structure and function. However, the precise changes in the coordination between brain structure and function in subcortical stroke patients remain unclear. We investigated alterations in brain structural-functional coupling (SC-FC coupling) and their impact on cognitive function in subcortical basal ganglia infarction patients.

METHODS

The study comprised 40 patients with mild stroke with basal ganglia region infarcts and 29 healthy controls (HC) who underwent multidimensional neuroimaging examination and neuropsychological testing. The subcortical stroke patients were divided into post-stroke cognitive impairment (PSCI) and stroke with no cognitive impairment (NPSCI) groups based on cognitive performance, with 22 individuals undergoing follow-up examination after three months. We investigated differences in brain structural-functional coupling across three groups, and their associations with cognitive functions.

RESULTS

Compared to both HC participants and NPSCI, PSCI exhibited significantly reduced structural-functional coupling strength in specific brain regions. After a three-month period, there was observed an increase in structural-functional coupling strength within the frontal lobe (precentral gyrus and paracentral lobule). The strength of SC-FC coupling within the precentral gyrus, precuneus, and paracentral lobule regions demonstrated a decline correlating with the deterioration of cognitive function (MoCA, memory and visual motor speed functions).

CONCLUSIONS

After subcortical basal ganglia stroke, PSCI patients demonstrated decreased SC-FC coupling in the frontal lobe region, correlating with multidimensional cognitive impairment. Three months later, there was an increase in SC-FC coupling in the frontal lobe, suggesting a compensatory mechanism during the recovery phase of cognitive impairment following stroke.

Identification of a cognitive network with effective connectivity to post-stroke cognitive impairment

Altered connectivity within complex functional networks has been observed in individuals with post-stroke cognitive impairment (PSCI) and during cognitive tasks. This study aimed to identify a cognitive function network that is responsive to cognitive changes during cognitive tasks and also sensitive to PSCI. To explore the network, we analyzed resting-state fMRI data from 20 PSCI patients and task-state fMRI data from 100 unrelated healthy young adults using functional connectivity analysis. We further employed spectral dynamic causal modeling to examine the effective connectivity among the pivotal regions within the network. Our findings revealed a common cognitive network that encompassed the hub regions 231 in the Subcortical network (SC), 70, 199, 242 in the Frontoparietal network (FP), 214 in the Visual II network, and 253 in the Cerebellum network (CBL). These hubs' effective connectivity, which showed reliable but slight changes during different cognitive tasks, exhibited notable alterations when comparing post-stroke cognitive impairment and improvement statuses. Decreased coupling strengths were observed in effective connections to CBL253 and from SC231 and FP70 in the improvement status. Increased connections to SC231 and FP70, from CBL253 and FP242, as well as from FP199 and FP242 to FP242 were observed in this status. These alterations exhibited a high sensitivity to signs of recovery, ranging from 80 to 100%. The effective connectivity pattern in both post-stroke cognitive statuses also reflected the influence of the MoCA score. This research succeeded in identifying a cognitive network with sensitive effective connectivity to cognitive changes after stroke, presenting a potential neuroimaging biomarker for forthcoming interventional studies.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11571-024-10139-4.

Exploring the Relationship between Abnormal Communication Efficiency of Cerebral Cortex and Multiple Cognitive Functions in Mild Subcortical Stroke: A Resting-State fMRI Study

BACKGROUND

The purpose of this study was to explore the specific regions of abnormal cortical communication efficiency in patients with mild subcortical stroke and to investigate the relationship between these communication efficiency abnormalities and multidimensional cognition.

METHODS

The research involved 35 patients with mild strokes affecting the basal ganglia and 29 healthy controls (HC). Comprehensive neuroimaging and neuropsychological assessments were conducted. Stroke patients were categorized into post-stroke cognitive impairment (PSCI) (MoCA ≤ 22) and non-cognitively impaired stroke patients (NPSCI) (MoCA ≥ 23) based on their cognitive performance. Additionally, 22 patients were reassessed three months later.

RESULTS

PSCI patients, compared to HC and NPSCI groups, had significantly higher communication efficiency in specific brain regions. A notable finding was the significant correlation between increased communication efficiency in the medioventral occipital cortex and multidimensional cognitive decline. However, this increased communication efficiency in PSCI patients lessened during the three-month follow-up period.

CONCLUSIONS

the heightened communication efficiency in the medio-ventral occipital cortex may represent a compensatory mechanism for cognitive impairment in PSCI patients, which undergoes adjustment three months after stroke.

Effects of brain atrophy and altered functional connectivity on poststroke cognitive impairment

BACKGROUND AND PURPOSE

Brain atrophy and disrupted functional connectivity are often present in patients with poststroke cognitive impairment (PSCI). This study aimed to explore the relationship between remote brain atrophy, connectional diaschisis and cognitive impairment in ischemic stroke patients to provide valuable information about the mechanisms underlying cognitive function recovery.

METHODS

Forty first-time stroke patients with basal ganglia infarcts and twenty-nine age-matched healthy people were enrolled. All participants underwent T1-weighted and functional MRI scans, comprehensive cognitive function assessments at baseline, and 3-month follow-up. Brain volumes were calculated, and the atrophic regions were regarded as regions of interest in seed-based functional connectivity analyses. Pearson correlation analysis was used to explore the relationships among cognitive performance, brain atrophy, and functional connectivity alterations.

RESULTS

Compared with healthy participants, stroke patients had worse cognitive performance at baseline and the 3-month follow-up. Worse cognitive performance was associated with smaller bilateral thalamus, left hippocampus, and left amygdala volumes, as well as lower functional connectivity between the left thalamus and the left medial superior frontal gyrus, between the right thalamus and the left median cingulate and paracingulate gyri, between the right hippocampus and the left medial superior frontal gyrus, and between the left amygdala and the right dorsolateral superior frontal gyrus.

CONCLUSIONS

In patients with basal ganglia infarction, connectional diaschisis between remote brain atrophy and the prefrontal lobe plays a significant role in PSCI. This finding provides new scientific evidence for understanding the mechanisms of PSCI and indicates that the prefrontal lobe may be a target to improve cognitive function after stroke.

Basal ganglia ischaemic infarction after thrombectomy: cognitive impairment at acute stage

BACKGROUND AND PURPOSE

After successful mechanical thrombectomy for middle cerebral artery occlusion, basal ganglia infarction is commonly detectable. Whilst the functional outcome of these patients is often good, less knowledge is available about the cognitive outcome. The aim of our study was to assess the presence of cognitive impairment within 1 week after thrombectomy.

METHODS

In all, 43 subjects underwent a general cognitive assessment using the Montreal Cognitive Assessment and an extensive battery of tests. Patients were classified as cognitively impaired (CImp) or not (noCImp) according to a Montreal Cognitive Assessment score below 18.

RESULTS

Cognitively impaired and noCImp subjects did not differ either in their National Institutes of Health Stroke Scale (NIHSS) and modified Rankin Scale (mRS) at admittance, or in their Fazekas score and Alberta Stroke Program Early Computed Tomography Score. At discharge, CImp subjects showed higher scores than noCImp subjects on NIHSS (p = 0.002) and mRS (p < 0.001). The percentage of pathological performances on each neuropsychological test in the whole sample and in CImp and noCImp patients shows a similar cognitive profile between the groups.

CONCLUSIONS

Some patients who underwent thrombectomy experienced a detectable cognitive impairment that probably led to worse NIHSS and mRS. The neuropsychological profile of such cognitive impairment at the acute stage consists of wide deficits in numerous cognitive domains, suggesting that basal ganglia damage may lead to complex functional impairments.

Cognitive decline as the main manifestation of diabetic striatal disease but without involuntary movements: a case report

Diabetic striatopathy (DS) is a rare central nervous system complication of diabetes mellitus, characterized mainly by non-ketotic hyperglycemia and lateralized involuntary movements. Patients with diabetic striatopathy manifested solely by subacute cognitive decline were rarely reported. In this paper, we report a patient with DS who presented solely with subacute cognitive decline without involuntary movements, and cranial CT showed bilateral high density in the basal ganglia. In contrast, SWI showed microhemorrhages in the right caudate nucleus head. After one week of treatment, including glycemic control, the patient showed significant improvement in cognitive function, while a repeat cranial CT showed improved hyperdensity in the right basal ganglia region. 1 month later, at telephone follow-up, the patient's symptoms did not recur.

Acute minocycline treatment inhibits microglia activation, reduces infarct volume, and has domain-specific effects on post-ischemic stroke cognition in rats

Ischemic stroke affects millions of individuals worldwide and a high prevalence of survivors experience cognitive deficits. At present, the underlying mechanisms that drive post-stroke cognitive decline are not well understood. Microglia play a critical role in the post-stroke inflammatory response, but experimental studies show that an accumulation of chronically activated microglia can be harmful and associates with cognitive impairment. This study assessed the effect of acute post-stroke minocycline treatment on chronic microglia and astrocyte expression within the infarct and remote white matter regions, as well as its effect on various domains of cognitive function post-stroke. Nine-month-old male rats received an injection of endothelin-1 into the right dorsal striatum to induce transient focal ischemia, and then were treated with minocycline or saline for 4 days post-stroke. Rats were tested using a series of lever-pressing tasks and the Morris water maze to assess striatal-based learning, cognitive flexibility, and spatial learning and reference memory. We found that minocycline-treated rats had smaller stroke-induced infarcts and less microglia activation in the infarct area and remote white matter regions compared to saline-treated rats at 28 days post-stroke. The behavioural testing results differed according to the cognitive domain; whereas minocycline-treated rats trended towards improved striatal-based learning in a lever-pressing task, but cognitive flexibility was unaffected during the subsequent set-shifting task. Furthermore, minocycline treatment unexpectedly impaired spatial learning, yet it did not alter reference memory. Collectively, we show that post-stroke minocycline treatment can reduce chronic microglia activation even in remote brain regions, with domain-specific effects on cognitive function.

MRI factors associated with cognitive functioning after acute onset brain injury: Systematic review and meta-analysis

Impairments of memory, attention, and executive functioning are frequently reported after acute onset brain injury. MRI markers hold potential to contribute to identification of patients at risk for cognitive impairments and clarification of mechanisms. The aim of this systematic review was to summarize and value the evidence on MRI markers of memory, attention, and executive functioning after acute onset brain injury. We included ninety-eight studies, on six classes of MRI factors (location and severity of damage (n = 15), volume/atrophy (n = 36), signs of small vessel disease (n = 15), diffusion-weighted imaging measures (n = 36), resting-state functional MRI measures (n = 13), and arterial spin labeling measures (n = 1)). Three measures showed consistent results regarding their association with cognition. Smaller hippocampal volume was associated with worse memory in fourteen studies (pooled correlation 0.58 [95% CI: 0.46-0.68] for whole, 0.11 [95% CI: 0.04-0.19] for left, and 0.34 [95% CI: 0.17-0.49] for right hippocampus). Lower fractional anisotropy in cingulum and fornix was associated with worse memory in six and five studies (pooled correlation 0.20 [95% CI: 0.08-0.32] and 0.29 [95% CI: 0.20-0.37], respectively). Lower functional connectivity within the default-mode network was associated with worse cognition in four studies. In conclusion, hippocampal volume, fractional anisotropy in cingulum and fornix, and functional connectivity within the default-mode network showed consistent associations with cognitive performance in all types of acute onset brain injury. External validation and cut off values for predicting cognitive impairments are needed for clinical implementation.

Montreal Cognitive Assessment of cognitive dysfunction after basal ganglia stroke

Objective

The Montreal Cognitive Assessment (MoCA) was used to evaluate cognitive dysfunction after basal ganglia stroke, and factors affecting total MoCA score were examined.

Methods

Data were retrospectively analyzed for 30 patients with basal ganglia intracerebral hemorrhage or basal ganglia cerebral infarction, who were admitted to The Second Affiliated Hospital of Fujian Traditional Medical University (Fujian, China) from January 2017 to March 2020. Cognitive impairment was assessed using the MoCA, and potential correlations were explored between clinicodemographic characteristics (sex, age, stroke location and etiology) and MoCA dimensions or total MoCA score.

Results

Univariate linear regression showed that the total MoCA score was significantly associated with sex, age, executive function, naming, attention, abstract generalization ability, memory ability, and visuospatial orientation. However, multivariate linear regression identified only executive function, naming, attention, memory ability, and visuospatial orientation as significantly associated with the total MoCA score.

Conclusions

We showed that the MoCA test can be used for patients with basal ganglia stroke. The total MoCA score of basal ganglia stroke was significantly associated with impairments in executive function, naming, attention, memory ability, and visuospatial orientation.

MRI tracking/detection of bone marrow mesenchymal stromal cells transplantation for treatment of ischemic cerebral infarction

Background

Cerebral stroke is the second leading cause of death with high mortality and morbidity worldwide, currently it lacks effective therapies to improve the prognosis. This study was aimed to explore the role of bone marrow mesenchymal stem cells (BMSCs) transplantation in the recovery of brain structure and function after ischemic cerebral infarction by magnetic resonance imaging (MRI).

Methods

By applying internal carotid artery embolization, the ischemic cerebral infarction model in rats was established. MRI was performed to detect the imaging changes in the brain tissue after modeling, and the successful modeling was evidenced by the presence of obvious high-signal infarct areas in the brain. BMSCs were then injected into the lateral ventricles of rats, and the recovery of brain tissue and function were quantitatively evaluated by T2-weighted image (T2WI) and voxel-based morphology (VBM) after 28 days.

Results

The results showed that BMSCs were cell subsets with multiple differentiation potentials. Deficits caused by Ischemic cerebral infarction were relieved by BMSCs transplantation, including increase in damaged cerebral tissue and recovery of cerebral function. In addition, the combined imaging technology of VBM and T2WI quantitatively revealed the effectiveness of BMSCs in repairing damaged brain tissue structure and function.

Conclusion

Taken together, the results revealed that the transplantation of BMSCs into the lateral ventricle was beneficial to repair the structure and function of the damaged brain tissue after ischemic cerebral infarction. Moreover, the combination of VBM and T2WI technology can detect the level of brain injury in ischemic cerebral infarction dynamically and noninvasively, and evaluate the recovery of structure and function of damaged brain tissue.

Childhood ischaemic stroke in the basal ganglia can lead to fine motor and anxiety disorders: a retrospective analysis and follow-up of 109 cases

Background

Stroke in children easily causes long-term dysfunction. Whether the prognoses of motor and anxiety disorders are related to the affected stroke area has not been reported.

Methods

One hundred nine cases of children with ischaemic stroke were reviewed and divided into three groups: lenticular nucleus lesions only (lenticular nucleus group), lenticular nucleus and caudate head lesions (caudate head group), and lenticular nucleus and thalamus lesions (thalamus group). Overall prognosis was evaluated by the mRS score. The SCAS-P was used to evaluate anxiety in children aged ≥6 years.

Results

mRS scores were ≤ 2 points (mean: 0.62), no significant difference among groups. 3/21 (14.2%) patients in the caudate head group changed handedness, which is significantly higher than other groups. Patients with lesions in thalamus group had significantly higher SCAS-P scores.

Conclusions

The overall prognosis of children with basal ganglia ischaemic stroke is good. However, hand preference changes and anxiety disorders may develop. Patients in the caudate head groups are more likely to suffer from fine motor disorders and changes in handedness. Patients within the thalamus group are more prone to anxiety than patients in the other groups. Anxiety disorders should be noted in children with basal ganglia stroke.

Diffusion Properties of Normal-Appearing White Matter Microstructure and Severity of Motor Impairment in Acute Ischemic Stroke

BACKGROUND AND PURPOSE

The effect of white matter hyperintensities as measured by FLAIR MR imaging on functional impairment and recovery after ischemic stroke has been investigated thoroughly. However, there has been growing interest in investigating normal-appearing white matter microstructural integrity following ischemic stroke onset with techniques such as DTI.

MATERIALS AND METHODS

Fifty-two patients with acute ischemic stroke and 36 without stroke were evaluated with a DTI and FLAIR imaging protocol and clinically assessed for the severity of motor impairment using the Motricity Index within 72 hours of suspected symptom onset.

RESULTS

There were widespread decreases in fractional anisotropy and increases in mean diffusivity and radial diffusivity for the acute stroke group compared with the nonstroke group. There was a significant positive association between fractional anisotropy and motor function and a significant negative association between mean diffusivity/radial diffusivity and motor function. The normal-appearing white matter ROIs that were most sensitive to the Motricity Index were the anterior/posterior limb of the internal capsule in the infarcted hemisphere and the splenium of the corpus callosum, external capsule, posterior limb/retrolenticular part of the internal capsule, superior longitudinal fasciculus, and cingulum (hippocampus) of the intrahemisphere/contralateral hemisphere.

CONCLUSIONS

The microstructural integrity of normal-appearing white matter is a significant parameter to identify neural differences not only between those individuals with and without acute ischemic stroke but also correlated with the severity of acute motor impairment.