MRI Lesion Load of Cerebral Small Vessel Disease and Cognitive Impairment in Patients With CADASIL

Contribution of the APOE Genotype to Cognitive Impairment in Individuals With NOTCH3 Cysteine-Altering Variants

BACKGROUND

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is the most prevalent monogenic cerebral small-vessel disease. Phenotype variability in CADASIL suggests the possible role of genetic modifiers. We aimed to investigate the contributions of the APOE genotype and Neurogenic locus notch homolog protein 3 (NOTCH3) variant position to cognitive impairment associated with CADASIL.

METHODS AND RESULTS

Patients with the cysteine-altering NOTCH3 variant were enrolled in a cross-sectional study, including the Mini-Mental State Examination (MMSE), brain magnetic resonance imaging, and APOE genotyping. Cognitive impairment was defined as an MMSE score <24. The associations between the MMSE score and genetic factors were assessed using linear regression models. Bayesian adjustment for confounding was used to identify clinical confounders. A total of 246 individuals were enrolled, among whom 210 (85%) harbored the p.R544C variant, 96 (39%) had cognitive impairment, and 150 (61%) had a history of stroke. The APOE ɛ2 allele was associated with a lower MMSE score (adjusted B, -4.090 [95% CI, -6.708 to -1.473]; P=0.023), whereas the NOTCH3 p.R544C variant was associated with a higher MMSE score (adjusted B, 2.854 [95% CI, 0.603-5.105]; P=0.0132) after adjustment for age, education, and history of ischemic stroke. Mediation analysis suggests that the associations between the APOE ɛ2 allele and MMSE score and between the NOTCH3 p.R544C variant and MMSE score are mediated by mesial temporal atrophy and white matter hyperintensity, respectively.

CONCLUSIONS

APOE genotype may modify cognitive impairment in CADASIL, whereby individuals carrying the APOE ɛ2 allele may present a more severe cognitive impairment.

The relevance of the socio-emotional deficits in cerebral small vessels disease (CSVD): An exploratory study with sporadic CSVD and CADASIL patients

Background

Cerebral Small Vessels Disease (CSVD) is categorized in different forms, the most common being the sporadic form and a genetic variant - Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL). Amongst the most frequent clinical manifestations are the neuropsychological changes of cognitive, behavioral, and emotional nature, whose features are still under debate.

Objective

This exploratory study aimed to compare the neuropsychological profile of a sporadic CSVD sample and a CADASIL sample with an age, education, and gender matched control group, between the ages of 30-65 YO (total sample mean age=51.16; SD=4.31).

Methods

20 patients with sporadic CSVD, 20 patients with CADASIL and 20 matched controls completed a neuropsychological assessment battery. Global cognitive state, processing speed, working memory, attention, executive dysfunction, episodic memory, social cognition, impulsivity, apathy, alexithymia, depression, and anxiety were measured. White matter hyperintensities (WMH) volume were quantified and measured as lesion burden.

Results

The cognitive differences found between the clinical groups combined (after confirming no differences between the two clinical groups) and matched controls were restricted to speed processing scores (d = 0.32 95 % CI [.12-.47]). The socio-emotional and behavioral profile revealed significantly higher levels of depression (d = 0.21, 95 % CI [.16-.33]). and anxiety (d = 0.25 95 % CI [.19-.32]) in CADASIL and sporadic CSVD groups, and the same for the alexithymia score (d = 0.533 95 % CI [.32-.65]) were the clinical groups revealed impoverished emotional processing compared to controls. WMH only significantly correlated with the cognitive changes and age.

Conclusions

In our study, CADASIL and sporadic cSVD patients combined, present multiple emotional-behavioral symptoms - alexithymia, anxiety, depression, and in a lower extent apathy and impulsivity - suggesting for the presence of emotion dysregulation behaviors, present independently of age and of the presence of cognitive deficits. Despite of the small sample size that could underpower some findings, this exploratory research supported that these symptoms may have a significant impact in disease monitoring, progression, and prognosis, requiring further investigation regarding their neurophysiological substrates.

A neuropsychological profile and its correlation with neuroimaging markers in patients with subcortical ischaemic vascular dementia

OBJECTIVES

Cognitive and neuroimaging assessments are still the main clinical practice methods for screening and diagnosing vascular dementia (VaD) patients. This study aimed to establish the neuropsychological characteristics of mild-to-moderate subcortical ischaemic vascular dementia (SIVD) patients, find an optimal cognitive marker for differentiating them from Alzheimer's disease (AD) patients, and explore the correlation between cognitive function and total small vessel disease (SVD) burden.

METHODS

SIVD (n = 60) and AD (n = 30) patients and cognitively unimpaired healthy controls (HCs; n = 30) were recruited from our longitudinal MRI AD and SIVD study (ChiCTR1900027943) and received a comprehensive neuropsychological assessment and a multimodal MRI scan. Cognitive performance and MRI SVD markers were compared between groups. Combined cognitive scores were established for differentiating between SIVD and AD patients. Correlations between cognitive function and total SVD scores were analysed in dementia patients.

RESULTS

SIVD patients showed poorer performance in information processing speed and better performance in memory, language, and visuospatial function than AD patients, although all cognitive domains were impaired in both groups compared with HCs. Combined cognitive scores showed an area under the curve of 0.727 (95%CI 0.62-0.84, p < 0.001) for differentiating SIVD and AD patients. Auditory Verbal Learning Test recognition scores were negatively correlated with total SVD scores in SIVD patients.

CONCLUSIONS

Our results suggested that neuropsychological assessments, specifically combined tests including episodic memory, information processing speed, language and visuospatial ability, are useful in the clinical differentiation between SIVD and AD patients. Moreover, cognitive dysfunction was partly correlated with MRI SVD burden in SIVD patients.

Imaging Characteristics for Predicting Cognitive Impairment in Patients With Cerebral Autosomal Dominant Arteriopathy With Subcortical Infarcts and Leukoencephalopathy

Objectives

Patients with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) show various clinical symptoms, including migraine, recurrent stroke, and cognitive impairment. We investigated the associations between magnetic resonance imaging (MRI) markers of small vessel disease and neuropsychological tests and identified the MRI characteristics for predicting cognitive impairment in patients with CADASIL.

Methods

Subjects included 60 CADASIL patients diagnosed with genetic tests and registered in the Japanese CADASIL REDCap database between June 2016 and December 2020. Patient information including clinical data, modified Rankin Scale (mRS); MRI findings of small vessel disease including periventricular and deep white matter lesions (WML), lacunar infarcts, and cerebral microbleeds (CMBs); and neuropsychological tests, including the Japanese version of the Mini-Mental State Examination (MMSE), the Japanese version of the Montreal Cognitive Assessment (MoCA-J), and the Frontal Assessment Battery (FAB), were evaluated.

Results

Data from 44 CADASIL patients were eligible for this study, compared between patients with and without dementia. Regarding the neuroimaging findings, the Fazekas score of periventricular and deep WML was higher in patients with dementia (periventricular, p = 0.003; deep, p = 0.009). The number of lacunar infarcts was higher in patients with dementia (p = 0.001). The standardized partial regression coefficient (SPRC) in MoCA-J was 0.826 (95% CI, 0.723-0.942; p = 0.005) for the number of CMBs. The SPRC in MMSE was 0.826 (95% CI, 0.719-0.949; p = 0.007) for the number of CMBs. The SPRC for FAB decreased significantly to 0.728 (95% CI, 0.551-0.960; p = 0.024) for the number of lacunar infarcts. Receiver operating characteristic (ROC) curves for dementia showed that in the number of lacunar infarcts, a cut-off score of 5.5 showed 90.9% sensitivity and 61.1% specificity. For the number of CMBs, a cut-off score of 18.5 showed 45.5% sensitivity and 100% specificity.

Conclusion

The characteristic MRI findings were that CADASIL patients with dementia had severe WML, both periventricular and deep, and a larger number of lacunar infarcts than those without dementia. The risk of dementia may be associated with ≥ 6 lacunar infarcts, ≥19 CMBs, or a Fazekas scale score of 3 in periventricular and deep WML.

Relationships Between Memory Impairments and Hippocampal Structure in Patients With Subcortical Ischemic Vascular Disease

Background and Purpose

Patients with subcortical ischemic vascular disease (SIVD) suffer from memory disorders that are thought to be associated with the hippocampus. We aimed to explore changes in hippocampal subfields and the relationship between different hippocampal subfield volumes and different types of memory dysfunction in SIVD patients.

Methods

A total of 77 SIVD patients with cognitive impairment (SIVD-CI, n = 39) or normal cognition (HC-SIVD, n = 38) and 41 matched healthy controls (HCs) were included in this study. Memory function was measured in all subjects, and structural magnetic resonance imaging (MRI) was performed. Then, the hippocampus was segmented and measured by FreeSurfer 6.0 software. One-way ANOVA was used to compare the volume of hippocampal subfields among the three groups while controlling for age, sex, education and intracranial volume (ICV). Then, post hoc tests were used to evaluate differences between each pair of groups. Finally, correlations between significantly different hippocampal subfield volumes and memory scores were tested in SIVD patients.

Results

Almost all hippocampal subfields were significantly different among the three groups except for the bilateral hippocampal fissure (p = 0.366, p = 0.086, respectively.) and left parasubiculum (p = 0.166). Furthermore, the SIVD-CI patients showed smaller volumes in the right subiculum (p &lt; 0.001), CA1 (p = 0.002), presubiculum (p = 0.002) and molecular layer of the hippocampus (p = 0.017) than the HC-SIVD patients. In addition, right subiculum volumes were positively related to Rey’s Auditory Verbal Learning Test (RAVLT) word recognition (r = 0.230, p = 0.050), reverse digit span test (R-DST) (r = 0.326, p = 0.005) and Rey–Osterrieth Complex Figure Test (ROCF) immediate recall (r = 0.247, p = 0.035) scores, right CA1 volumes were positively correlated with RAVLT word recognition (r = 0.261, p = 0.026), and right presubiculum volumes showed positive relationships with R-DST (r = 0.254, p = 0.030) and ROCF immediate recall (r = 0.242, p = 0.039) scores.

Conclusion

SIVD might lead to general reductions in volume in multiple hippocampal subfields. However, SIVD-CI patients showed atrophy in specific subfields, which might be associated with memory deficits.

Specific Abnormalities in White Matter Pathways as Interface to Small Vessels Disease and Cognition in Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy Individuals

Background: Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is characterized by leukoencephalopathy leading to cognitive impairment. Subtle cognitive deficits can be observed early in the course of the disease, before the occurrence of the first stroke. Therefore, markers that can predict disease progression at this early stage, when interventions are likely to alter disease course, are needed. We aimed to examine the biological cascade of microstructural and macrostructural white matter (WM) abnormalities underlying cognitive deficits in CADASIL. Methods: We examined 20 nondemented CADASIL mutation carriers and 23 noncarriers who underwent neuropsychological evaluation and magnetic resonance imaging. Using probabilistic tractography of key WM tracts, we examined group differences in diffusivity measures and WM hyperintensity volume. Successive mediation models examined whether tract-specific WM abnormalities mediated subtle cognitive differences between CADASIL mutation carriers and noncarriers. Results: The largest effect size differentiating the two groups was observed for left superior longitudinal fasciculus-temporal (SLFt) diffusivity (Cohen's f = 0.49). No group differences were observed with a global diffusion measure. These specific microstructural differences in the SLFt were associated with higher WM hyperintensities burden, and subtle executive deficits in CADASIL mutation carriers. Discussion: Worse diffusivity in the left SLFt is related to greater severity of small vessel disease and worse executive functioning in the asymptomatic stage of the disease. Worse diffusivity of the left SLFt may potentially hold promise as an indicator of disease progression. Impact statement Diffusion tensor imaging outperforms conventional imaging of subcortical small vessel disease as a potential marker of future disease progression. Here we identified the left superior longitudinal temporal fasciculus as a critical white matter fiber bundle, of which worse diffusivity can link presence of cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy mutations to greater severity of small vessel disease and worse executive functioning in asymptomatic stages of the disease. This tract may hold promise and deserves further examination as an early indicator of disease progression.

Prevalence and Consequences of Cerebral Small Vessel Diseases: A Cross-Sectional Study Based on Community People Plotted Against 5-Year Age Strata

PURPOSE

To study the variation tendency of cerebral small vessel disease (CSVD) imaging markers and total burden with aging and to research the relationship between aging, CSVD markers and cognitive function.

METHODS

Participants in local urban communities were recruited for neuropsychological and magnetic resonance imaging assessments. Montreal Cognitive Assessment (MoCA), Mini-mental State Examination (MMSE), Number Connection Test A (NCT-A) and Digital Symbol Test (DST) were adopted as neuropsychological scale. Age was stratified at 5-year intervals, and the variation tendency of imaging markers and variables of neuropsychological scales in different age groups was studied. We further studied the relationship between aging, image markers and neuropsychological scales by multi-linear regression.

RESULTS

Finally, a total of 401 stroke-free participants (age, 54.83±7.74y; 45.9% were male) were included in the present analysis. With the increase of age, the incidence of imaging markers of CSVD were increased with aging except cerebral microbleeds. The performance results of NCT-A and DST were significant difference in 6 age groups (P < 0.001). In addition, linear decline of the neuropsychological function reflected by NCT-A and DST variables was observed. Linear regression found that age was an independent factor affecting the neuropsychological function reflected by NCT-A and DST variables, and the standard correction coefficients among different age groups increased gradually with age. In addition, brain atrophy is an independent factor affecting neuropsychological variables (odds ratio: -2.929, 95% CI: [-5.094 to -0.765]). There was no correlation between the number of neuroimaging markers and neuropsychological variables after full adjustment.

CONCLUSION

There are many CVSD markers even in younger people, the incidence rate and CVSD marker numbers increase with age. Aging and CSVD may eventually affect cognitive function through brain atrophy.

Addition of Aβ42 to Total Cerebral Small Vessel Disease Score Improves the Prediction for Cognitive Impairment in Cerebral Small Vessel Disease Patients

PURPOSE

To investigate the associations between concentrations of Aβ₄₀ and Aβ₄₂ and vascular cognitive impairment (VCI) in cerebral small vessel disease (CSVD) patients and evaluate the value of combination of levels of Aβ₄₀ or Aβ₄₂ and the total CSVD score in predicting VCI.

PATIENTS AND METHODS

A total of 199 CSVD patients were divided into VCI group and non-VCI group according to the criteria of VCI. Demographic data, MRI markers of CSVD, blood pressure, vascular risk factors, laboratory markers, and serum Aβ₄₀ and Aβ₄₂ concentration were collected. Univariate analysis was performed with the Student's t-test, Mann-Whitney U-test or Chi-square test. Variables with P<0.10 in univariate analysis were then included in multivariate analysis that used a backward stepwise logistic regression model. The predictive values were assessed with receiver operating characteristic (ROC) curve.

RESULTS

VCI was determined in 112 CSVD patients (56.3%). Hyperlipidemia (OR: 1.618, 95% CI: 1.265-3.049), the total CSVD score (OR: 1.414, 95% CI: 1.213-2.278) and serum Aβ₄₂ concentration (OR: 1.401, 95% CI: 1.212-1.946) were independent risk factors for VCI in CSVD patients with adjustment for age, education years, diabetes and fasting blood-glucose (FBG). The area under curves (AUCs) were 0.640 (SE: 0.040, 95% CI: 0.563-0.718), 0.733 (SE: 0.035, 95% CI: 0.664-0.802) and 0.827 (SE: 0.030, 95% CI: 0.768-0.887), respectively, for the total CSVD score, serum Aβ₄₂ concentration and their combination applied in predicting VCI in CSVD patients. Z test demonstrated that the AUC of combination prediction was significantly higher than individual prediction (0.827 vs 0.640, Z=3.740, P<0.001; 0.827 vs 0.733, Z=2.039, P=0.021).

CONCLUSION

Combination of Aβ₄₂ and total CSVD score could significantly elevate the predictive value of cognitive impairment in CSVD patients.

Altered Regional Brain Homogeneity of BOLD Signal in CADASIL: A Resting State fMRI Study

BACKGROUND AND PURPOSE

The cognitive decline in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is assumed to be due to a cortical-subcortical disconnection secondary to damage to the cerebral white matter (WM). Using resting state functional MRI (rsfMRI) and analysis of the regional homogeneity (ReHo), we examined a group of CADASIL patients and a group of healthy subjects in order to: (1) explore possible differences between the two groups; and (2) to assess, in CADASIL patients, whether any ReHo abnormalities correlate with individual burdens of WM T₂ -weighted hyperintensity and diffusion tensor imaging (DTI)-derived index of mean diffusivity (MD) of the cerebral WM, an index reflecting microstructural damage in CADASIL.

METHODS

Twenty-three paucisymptomatic CADASIL patients (13 females; age mean ± standard deviation = 43.6 ± 11.1 years; three symptomatic and 20 with no or few symptoms) and 16 healthy controls (nine females; age 46.6 ± 11.0 years) were examined with T₁ -weighted, T₂ -weighted fluid attenuated inversion recovery images, DTI, and rsfMRI.

RESULTS

When compared to controls, CADASIL patients showed four clusters of significantly lower ReHo values in cortical areas belonging to networks involved in inhibition and attention, including the right insula, the left superior frontal gyrus, and the bilateral anterior cingulated cortex. ReHo changes did not correlate with an individual patient's lesion burden or MD.

CONCLUSIONS

This study reveals decreased ReHo of rsfMRI signals in cortical areas involved in inhibition and attention processes, suggesting a potential role for these functional cortical changes in CADASIL.

Iron leakage owing to blood–brain barrier disruption in small vessel disease CADASIL

Objective

To assess the relationship among iron accumulation, blood–brain barrier (BBB) damage, and cognitive function in patients with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL).

Methods

We enrolled 21 patients with NOTCH3 mutations and 21 age-matched healthy controls in this cross-sectional study. All participants underwent global physical and cognitive assessments and brain MRI using voxel-based quantitative susceptibility mapping (QSM; iron deposition measure) and dynamic contrast-enhanced MRI (BBB permeability measure). We compared behavioral and imaging data between the groups and analyzed the correlations in each group.

Results

Among 21 NOTCH3 mutation carriers, 10 were symptomatic and 11 asymptomatic. Montreal Cognitive Assessment scores were significantly different among the groups (symptomatic < asymptomatic < control participants). Voxel-based QSM analysis revealed that the symptomatic group had higher QSM values than did the asymptomatic group in the putamen, caudate nucleus, temporal pole, and centrum semiovale. These QSM values were positively correlated with regional BBB permeabilities (putamen: r = 0.57, p = 0.006; caudate nucleus: r = 0.51, p = 0.019; temporal pole: r = 0.48, p = 0.030; centrum semiovale: r = 0.45, p = 0.044) and negatively correlated with Montreal Cognitive Assessment scores (caudate nucleus: r = −0.53, p = 0.012; temporal pole: r = −0.56, p = 0.008).

Conclusions

This study showed that cerebral iron burden was associated with regional BBB permeability and cognitive dysfunction in patients with CADASIL, highlighting the potential of these imaging techniques as auxiliary biomarkers to monitor the course of small vessel disease.

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy revisited: Genotype-phenotype correlations of all published cases

Objective

The aim of this study was to evaluate the correlation between the various NOTCH3 mutations and their clinical and genetic profile, along with the presentation of a novel mutation in a patient.

Methods

Here, we describe the phenotype of a patient with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) harboring a novel mutation. We also performed an extensive literature research for NOTCH3 mutations published since the identification of the gene and performed a systematic review of all published cases with NOTCH3 mutations. We evaluated the mutation pathogenicity in a great number of patients with detailed clinical and genetic evaluation and investigated the possible phenotype-genotype correlations.

Results

Our patient harbored a novel mutation in the NOTCH3 gene, the c.3084 G > C, corresponding to the aminoacidic substitution p.Trp1028Cys, presenting with seizures as the first neurologic manifestation. We managed to find a correlation between the pathogenicity of mutations, severity of the phenotype, and age at onset of CADASIL. Significant differences were also identified between men and women regarding the phenotype severity.

Conclusions

The collection and analysis of these scarce data published since the identification of NOTCH3 qualitatively by means of a systematic review and quantitatively regarding genetic profile and pathogenicity scores, highlight the significance of the ongoing trend of investigating phenotypic genotypic correlations.

Reduced resting-state brain functional network connectivity and poor regional homogeneity in patients with CADASIL

BACKGROUND

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) manifests principally as a suite of cognitive impairments, particularly in the executive domain. Executive functioning requires the dynamic coordination of neural activity over large-scale networks. It remains unclear whether changes in resting-state brain functional network connectivity and regional homogeneities (ReHos) underly the mechanisms of executive dysfunction evident in CADASIL patients.

METHODS

In this study, 22 CADASIL patients and 44 matched healthy controls underwent resting-state functional magnetic resonance imaging (fMRI). Independent component analysis (ICA) was used to measure functional brain network connectivity, and ReHos were calculated to evaluate local brain activities. We used seed-based functional connectivity (FC) analyses to determine whether dysfunctional areas (as defined by ReHos) exhibited abnormal FC with other brain areas. Relationships among the mean intra-network connectivity z-scores of dysfunctional areas within functional networks, and cognitive scores were evaluated using Pearson correlation analyses.

RESULTS

Compared to the controls, CADASIL patients exhibited decreased intra-network connectivity within the bilateral lingual gyrus (LG) and the right cuneus (CU) (thus within the visual network [VIN)], and within the right precuneus (Pcu), inferior frontal gyrus (IFG), and precentral gyrus (thus within the frontal network [FRN]). Compared to the controls, patients also exhibited significantly lower ReHos in the right precuneus and cuneus (Pcu/CU), visual association cortex, calcarine gyri, posterior cingulate, limbic lobe, and weaker FC between the right Pcu/CU and the bilateral parahippocampal gyrus (PHG), and between the right Pcu/CU and the right postcentral gyrus. Notably, the mean connectivity z-scores of the bilateral LG and the right CU within the VIN were positively associated with compromised attention, calculation and delayed recall as revealed by tests of the various cognitive domains explored by the Mini-Mental State Examination.

CONCLUSIONS

The decreases in intra-network connectivity within the VIN and FRN and reduced local brain activity in the posterior parietal area suggest that patients with CADASIL may exhibit dysfunctional visuomotor behaviors (a hallmark of executive function), and that all visual information processing, visuomotor planning, and movement execution may be affected.