Quantitative MR evaluation of atrophy, as well as perfusion and diffusion alterations within hippocampi in patients with Alzheimer's disease and mild cognitive impairment

Brain atrophy pattern in patients with mild cognitive impairment: MRI study

We evaluated the accuracy of the quantitative and semiquantitative analysis in detecting regional atrophy patterns and differentiating mild cognitive impairment patients who remain stable (aMCI-S) from patients who develop Alzheimer’s disease (aMCI-AD) at clinical follow-up. Baseline magnetic resonance imaging was used for quantitative and semiquantitative analysis using visual rating scales. Visual rating scores were related to gray matter thicknesses or volume measures of some structures belonging to the same brain regions. Receiver operating characteristic (ROC) analysis was performed to assess measures’ accuracy in differentiating aMCI-S from aMCI-AD. Comparing aMCI-S and aMCI-AD patients, significant differences were found for specific rating scales, for cortical thickness belonging to the middle temporal lobe (MTL), anterior temporal (AT), and fronto-insular (FI) regions, for gray matter volumes belonging to MTL and AT regions. ROC curve analysis showed that middle temporal atrophy, AT, and FI visual scales showed better diagnostic accuracy than quantitative measures also when thickness measures were combined with hippocampal volumes. Semiquantitative evaluation, performed by trained observers, is a fast and reliable tool in differentiating, at the early stage of disease, aMCI patients that remain stable from those patients that may progress to AD since visual rating scales may be informative both about early hippocampal volume loss and cortical thickness reduction.

Evaluation of Fundus Blood Flow Perfusion in Patients with Diabetic Retinopathy after PPV with Fundus Color Doppler Based on Big Data Mining

In this paper, we have carefully investigated the clinical phenotype and genotype of patients with Johanson-Blizzard syndrome (JBS) with diabetes mellitus as the main manifestation. Retinal vessel segmentation is an important tool for the detection of many eye diseases and plays an important role in the automated screening system for retinal diseases. A segmentation algorithm based on a multiscale attentional resolution network is proposed to address the problem of insufficient segmentation of small vessels and pathological missegmentation in existing methods. The network is based on the encoder-decoder architecture, and the attention residual block is introduced in the submodule to enhance the feature propagation ability and reduce the impact of uneven illumination and low contrast on the model. The jump connection is added between the encoder and decoder, and the traditional pooling layer is removed to retain sufficient vascular detail information. Two multiscale feature fusion methods, parallel multibranch structure, and spatial pyramid pooling are used to achieve feature extraction under different sensory fields. We collected the clinical data, laboratory tests, and imaging examinations of JBS patients, extracted the genomic DNA of relevant family members, and validated them by whole-exome sequencing and Sanger sequencing. The patient had diabetes mellitus as the main manifestation, with widened eye spacing, low flat nasal root, hypoplastic nasal wing, and low hairline deformities. Genetic testing confirmed the presence of a c.4463 T > C (p.Ile1488Thr) pure missense mutation in the UBR1 gene, which was a novel mutation locus, and pathogenicity analysis indicated that the locus was pathogenic. This patient carries a new UBR1 gene c.4463 T > C pure mutation, which improves the clinical understanding of the clinical phenotypic spectrum of JBS and broadens the genetic spectrum of the UBR1 gene. The experimental results showed that the method achieved 83.26% and 82.56% F1 values on CHASEDB1 and STARE standard sets, respectively, and 83.51% and 81.20% sensitivity, respectively, and its performance was better than the current mainstream methods.

Identification and Classification of Alzheimer's Disease Patients Using Novel Fractional Motion Model

Most diffusion magnetic resonance imaging (dMRI) techniques use the mono-exponential model to describe the diffusion process of water in the brain. However, the observed dMRI signal decay curve deviates from the mono-exponential form. To solve this problem, the fractional motion (FM) model has been developed, which is regarded as a more appropriate model for describing the complex diffusion process in brain tissue. It is still unclear in the identification and classification of Alzheimer's disease (AD) patients using the FM model. The purpose of this study was to investigate the potential feasibility of FM model for differentiating AD patients from healthy controls and grading patients with AD. Twenty-four patients with AD and 11 healthy controls were included. The left and right hippocampus were selected as regions of interest (ROIs). The apparent diffusion coefficient (ADC) values and FM-related parameters, including the Noah exponent (α), the Hurst exponent (H), and the memory parameter (μ=H-1/α), were calculated and compared between AD patients and healthy controls and between mild AD and moderate AD patients using a two-sample t-test. The correlations between FM-related parameters α, H, μ, and ADC values and the cognitive functions assessed by mini-mental state examination (MMSE) and Montreal cognitive assessment (MoCA) scales were investigated using Pearson partial correlation analysis in patients with AD. The receiver-operating characteristic analysis was used to assess the differential performance. We found that the FM-related parameter α could be used to distinguish AD patients from healthy controls (P < 0.05) with greater sensitivity and specificity (left ROI, 0.917 and 0.636; right ROI, 0.917 and 0.727) and grade AD patients (P < 0.05) showed higher sensitivity and specificity (right ROI, 0.917, 0.75). The α was found to be positively correlated with MMSE (P < 0.05) and MoCA (P < 0.05) scores in patients with AD, indicating that the α values in the bilateral hippocampus were a potential MRI-based biomarker of disease severity in AD patients. This novel diffusion model may be useful for further understanding neuropathologic changes in patients with AD.

Characterization of Alzheimer's Disease Using Ultra-high b-values Apparent Diffusion Coefficient and Diffusion Kurtosis Imaging

The aim of the study is to investigate the diffusion characteristics of Alzheimer’s disease (AD) patients using an ultra-high b-values apparent diffusion coefficient (ADC_uh) and diffusion kurtosis imaging (DKI). A total of 31 AD patients and 20 healthy controls (HC) who underwent both MRI examination and clinical assessment were included in this study. Diffusion weighted imaging (DWI) was acquired with 14 b-values in the range of 0 and 5000 s/mm². Diffusivity was analyzed in selected regions, including the amygdala (AMY), hippocampus (HIP), thalamus (THA), caudate (CAU), globus pallidus (GPA), lateral ventricles (LVe), white matter (WM) of the frontal lobe (FL), WM of the temporal lobe (TL), WM of the parietal lobe (PL) and centrum semiovale (CS). The mean, median, skewness and kurtosis of the conventional apparent diffusion coefficient (ADC), DKI (including two variables, D_app and K_app) and ADC_uh values were calculated for these selected regions. Compared to the HC group, the ADC values of AD group were significantly higher in the right HIP and right PL (WM), while the ADC_uh values of the AD group increased significantly in the WM of the bilateral TL and right CS. In the AD group, the K_app values in the bilateral LVe, bilateral PL/left TL (WM) and right CS were lower than those in the HC group, while the D_app value of the right PL (WM) increased. The ADC_uh value of the right TL was negatively correlated with MMSE (mean, r=-0.420, p=0.019). The ADC value and D_app value have the same regions correlated with MMSE. Compared with the ADC_uh, combining ADC_uh and ADC parameters will result in a higher AUC (0.894, 95%CI=0.803-0.984, p=0.022). Comparing to ADC or DKI, ADC_uh has no significant difference in the detectability of AD, but ADC_uh can better reflect characteristic alternation in unconventional brain regions of AD patients.

AVRA: Automatic visual ratings of atrophy from MRI images using recurrent convolutional neural networks

Quantifying the degree of atrophy is done clinically by neuroradiologists following established visual rating scales. For these assessments to be reliable the rater requires substantial training and experience, and even then the rating agreement between two radiologists is not perfect. We have developed a model we call AVRA (Automatic Visual Ratings of Atrophy) based on machine learning methods and trained on 2350 visual ratings made by an experienced neuroradiologist. It provides fast and automatic ratings for Scheltens' scale of medial temporal atrophy (MTA), the frontal subscale of Pasquier's Global Cortical Atrophy (GCA-F) scale, and Koedam's scale of Posterior Atrophy (PA). We demonstrate substantial inter-rater agreement between AVRA's and a neuroradiologist ratings with Cohen's weighted kappa values of κw = 0.74/0.72 (MTA left/right), κw = 0.62 (GCA-F) and κw = 0.74 (PA). We conclude that automatic visual ratings of atrophy can potentially have great scientific value, and aim to present AVRA as a freely available toolbox.

Impaired chemoreflex correlates with decreased c-Fos in respiratory brainstem centers of the streptozotocin-induced Alzheimer's disease rat model

Besides impairment in cognition and memory, patients with Alzheimer's disease (AD) often exhibit marked dysfunction in respiratory control. Sleep-disordered breathing (SDB) is commonly found in cases of AD, resulting in periods of hypoxia during sleep. Early structural changes in brainstem areas controlling respiratory function may account for SDB in the course of AD. However, to date the underlying mechanisms for these complications are not known. The streptozotocin (STZ)-induced rat model of AD exhibits abnormal responses to hypoxia and increased astrogliosis in a key region for respiratory control. In this study we further defined the pathophysiological respiratory response of STZ-AD rats to 10% O₂. In addition, we analyzed hypoxia-induced neuronal activation in respiratory and cardiovascular nuclei of the dorsal and ventral brainstem. Two hours of hypoxia induced a transient increase in tidal volume that was followed by a prolonged increase in respiratory rate. Only respiratory rate was significantly blunted in the STZ-AD model, which continued over the entire duration of the hypoxic episode. Analysis of c-Fos expression as a marker for neuronal activation showed abundant labeling throughout the nTS, nuclei of the ventral respiratory column, and A1/C1 cells of cardiovascular centers in the ventral brainstem. STZ-AD rats showed a significant decrease of c-Fos labeling in the caudal/medial nTS, rostral ventral respiratory group, and Bötzinger complex. c-Fos in other respiratory centers and A1/C1 cells was unaltered when compared to control. The results of this study document a region-specific impact of STZ-induced AD in respiratory brainstem nuclei. This decrease in c-Fos expression correlates with the observed blunting of respiration to hypoxia in the STZ-AD rat model.

Multi-modal MRI investigation of volumetric and microstructural changes in the hippocampus and its subfields in mild cognitive impairment, Alzheimer's disease, and dementia with Lewy bodies

BACKGROUND

Volumetric atrophy and microstructural alterations in diffusion tensor imaging (DTI) measures of the hippocampus have been reported in people with Alzheimer's disease (AD) and mild cognitive impairment (MCI). However, no study to date has jointly investigated concomitant microstructural and volumetric changes of the hippocampus in dementia with Lewy bodies (DLB).

METHODS

A total of 84 subjects (23 MCI, 17 DLB, 14 AD, and 30 healthy controls) were recruited for a multi-modal imaging (3T MRI and DTI) study that included neuropsychological evaluation. Freesurfer was used to segment the total hippocampus and delineate its subfields. The hippocampal segmentations were co-registered to the mean diffusivity (MD) and fractional anisotropy (FA) maps obtained from the DTI images.

RESULTS

Both AD and MCI groups showed significantly smaller hippocampal volumes compared to DLB and controls, predominantly in the CA1 and subiculum subfields. Compared to controls, hippocampal MD was elevated in AD, but not in MCI. DLB was characterized by both volumetric and microstructural preservation of the hippocampus. In MCI, higher hippocampal MD was associated with greater atrophy of the hippocampus and CA1 region. Hippocampal volume was a stronger predictor of memory scores compared to MD within the MCI group.

CONCLUSIONS

Through a multi-modal integration, we report novel evidence that the hippocampus in DLB is characterized by both macrostructural and microstructural preservation. Contrary to recent suggestions, our findings do not support the view that DTI measurements of the hippocampus are superior to volumetric changes in characterizing group differences, particularly between MCI and controls.

The Disconnection Hypothesis in Alzheimer's Disease Studied Through Multimodal Magnetic Resonance Imaging: Structural, Perfusion, and Diffusion Tensor Imaging

According to the so-called disconnection hypothesis, the loss of synaptic inputs from the medial temporal lobes (MTL) in Alzheimer's disease (AD) may lead to reduced activity of target neurons in cortical areas and, consequently, to decreased cerebral blood flow (CBF) in those areas. The aim of this study was to assess whether hypoperfusion in parietotemporal and frontal cortices of patients with mild cognitive impairment who converted to AD (MCI-c) and patients with mild AD is associated with atrophy in the MTL and/or microstructural changes in the white matter (WM) tracts connecting these areas. We assessed these relationships by investigating correlations between CBF in hypoperfused areas, mean cortical thickness in atrophied regions of the MTL, and fractional anisotropy (FA) in WM tracts. In the MCI-c group, a strong correlation was observed between CBF of the superior parietal gyri and FA in the parahippocampal tracts (left: r = 0.90, p <  0.0001; right: r = 0.597, p = 0.024), and between FA in the right parahippocampal tract and the right precuneus (r = 0.551, p = 0.041). No significant correlations between CBF in hypoperfused regions and FA in the WM tract were observed in the AD group. These results suggest an association between perfusion deficits and altered WM tracts in prodromal AD, while microvasculature impairments may have a greater influence in more advanced stages. We did not find correlations between cortical thinning in the medial temporal lobes and decreased FA in the WM tracts of the limbic system in either group.

Interleukin-1beta-induced reduction of tissue water diffusion in the juvenile rat brain on ADC MRI is not associated with 31P MRS-detectable energy failure

Background

It has long been known that an intrastriatal microinjection of the archetypal pro-inflammatory cytokine, interleukin-1beta (IL-1β), in juvenile rats induces a chronic reduction in the apparent diffusion coefficient (ADC) of tissue water on magnetic resonance imaging (MRI). Reduced ADC during acute cerebral ischaemia is an established indicator of metabolic failure whereas the cause of the IL-1β-induced reduction remains to be deciphered. Previously, it has been shown that IL-1β does not perturb the phosphorus (³¹P) magnetic resonance spectroscopy (MRS)-detectable energy status of an ex vivo preparation of rat brain parenchyma that is devoid of a functional vasculature component. However, brain energy status following an IL-1β challenge in vivo remains to be examined.

Methods

This study is the first longitudinal in vivo examination of the correlation of ADC MRI with localised ³¹P MRS signals obtained specifically from within the injected and non-injected striatum following IL-1β (1 ng/ul or 100 ng/ul) challenge, in real-time.

Results

Despite observing a chronic reduction in ADC at either dose of IL-1β challenge, energy compromise was not detected at any time point.

Conclusions

The IL-1β-induced effects pertaining to a functional vasculature such as leukocyte recruitment, blood–brain barrier (BBB) breakdown and blood flow changes are unlikely to impact on overall tissue energy status. Compared to classic ischaemia, there is dissociation between ADC and energy status within an IL-1β-induced lesion in vivo.

Quantitative multimodal multiparametric imaging in Alzheimer's disease

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder, causing changes in memory, thinking, and other dysfunction of brain functions. More and more people are suffering from the disease. Early neuroimaging techniques of AD are needed to develop. This review provides a preliminary summary of the various neuroimaging techniques that have been explored for in vivo imaging of AD. Recent advances in magnetic resonance (MR) techniques, such as functional MR imaging (fMRI) and diffusion MRI, give opportunities to display not only anatomy and atrophy of the medial temporal lobe, but also at microstructural alterations or perfusion disturbance within the AD lesions. Positron emission tomography (PET) imaging has become the subject of intense research for the diagnosis and facilitation of drug development of AD in both animal models and human trials due to its non-invasive and translational characteristic. Fluorodeoxyglucose (FDG) PET and amyloid PET are applied in clinics and research departments. Amyloid beta (Aβ) imaging using PET has been recognized as one of the most important methods for the early diagnosis of AD, and numerous candidate compounds have been tested for Aβ imaging. Besides in vivo imaging method, a lot of ex vivo modalities are being used in the AD researches. Multiphoton laser scanning microscopy, neuroimaging of metals, and several metal bioimaging methods are also mentioned here. More and more multimodality and multiparametric neuroimaging techniques should improve our understanding of brain function and open new insights into the pathophysiology of AD. We expect exciting results will emerge from new neuroimaging applications that will provide scientific and medical benefits.

Cognitive Results of CANTAB Tests and Their Change Due to the First Dose of Donepezil May Predict Treatment Efficacy in Alzheimer Disease

Background

Ability to predict the efficacy of treatment in Alzheimer disease (AD) may be very useful in clinical practice. Cognitive predictors should be investigated alongside with the demographic, genetic, and other predictors of treatment efficacy. The aim of this study was to establish whether the baseline measures of CANTAB tests and their changes due to the first donepezil dose are able to predict the efficacy of treatment after 4 months of therapy. We also compared the predictive value of cognitive, clinical, and demographic predictors of treatment efficacy in AD.

Material/Methods

Seventy-two AD patients (62 treatment-naïve and 10 donepezil-treated) and 30 controls were enrolled in this prospective, randomized, rater-blinded, follow-up study. Treatment-naïve AD patients were randomized to 2 groups to take the first donepezil dose after the first or second CANTAB testing, separated by 4 hours. Follow-up Test 3 was performed 4 months after the initial assessment.

Results

The groups were similar in age, education, gender, Hachinski index, and depression. General Regression Models (GRM) have shown that cognitive changes after the first dose of donepezil in PAL (t-values for regression coefficients from 3.43 to 6.44), PRMd (t=4.33), SWM (t=5.85) test scores, and baseline results of PAL (t=2.57–2.86), PRM (t=3.08), and CRT (t=3.42) tests were significant predictors of long-term donepezil efficacy in AD (p<0.05).

Conclusions

The cognitive changes produced by the first donepezil dose in CANTAB PAL, PRM, and SWM test measures are able to predict the long-term efficacy of donepezil in AD. Baseline PAL, PRM, and CRT test results were significant predictors.

Selective Ability of Some CANTAB Battery Test Measures to Detect Cognitive Response to a Single Dose of Donepezil in Alzheimer Disease

Background

The Cambridge Neuropsychological Test Automated Battery (CANTAB) was used to explore which tests and their measures are able to detect cognitive change after a single dose of donepezil in Alzheimer disease (AD) patients. The aim of this study was to establish the ability of CANTAB tests and their measures to detect cognitive change after a single 5-mg dose of donepezil in treatment-naïve AD patients.

Material/Methods

We enrolled 62 treatment-naïve AD patients and 30 healthy controls in this prospective, randomized, rater-blinded study. AD patients were randomized to 2 groups: the AD+ group received donepezil after the first CANTAB testing and the AD− group remained treatment-naïve at second testing. The time period between repeated testing was 4 hours. Parallel versions of CRT, SOC, PAL, SWM, and PRM tests were used.

Results

All groups did not differ according to age, education, gender, or depression (p>0.05). AD+ and AD− groups did not differ according to MMSE. SOC, PAL, PRM, and SWM tests distinguished AD from controls. Eight measures of PAL and PRM had a strong correlation with MMSE (r>0.7). Repeated-measures ANOVA with Bonferroni post-hoc test showed the difference of change in AD+ and AD− groups between first and second CANTAB testing in 7 PAL measures. AD+ and AD− groups differed in the second testing by 7 PAL measures. Four PAL measures differed in first and second testing within the AD+ group.

Conclusions

The CANTAB PAL test measures, able to detect cognitive change after a single dose of donepezil in AD patients, are: PAL mean trials to success, total errors (adjusted), total errors (6 shapes, adjusted), and total trials (adjusted).

Butyrylcholinesterase K variant and Alzheimer's disease risk: a meta-analysis

Background

Although many studies have estimated the association between the butyrylcholinesterase (BCHE) K variant and Alzheimer’s disease (AD) risk, the results are still controversial. We thus conducted this meta-analysis.

Material/Methods

We searched NCBI, Medline, Web of Science, and Embase databases to find all eligible studies. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of the association.

Results

We found a significant association between BCHE K variant and AD risk (OR=1.20; 95% CI 1.03–1.39; P=0.02). In the stratified analysis by ethnicity, we observed a significant association between BCHE K variant and AD risk in Asians (OR=1.32; 95% CI 1.02–1.72; P=0.04). However, no significant association between BCHE K variant and AD risk in Caucasians was found (OR=1.14; 95% CI 0.95–1.37; P=0.16). When stratified by the age of AD onset, we found that late-onset AD (LOAD) was significantly associated with BCHE K variant (OR=1.44; 95% CI 1.05–1.97; P=0.02). No significant association between BCHE K variant and early-onset AD (EOAD) risk was observed (OR=1.16; 95% CI 0.89–1.51; P=0.27). Compared with non-APOE ɛ4 and non-BCHE K carriers, no significant association between BCHE K variant and AD risk was found (OR=1.11; 95% CI 0.91–1.35; P=0.30). However, APOE ɛ4 carriers showed increased AD risk in both non-BCHE K carriers (OR=2.81; 95% CI 1.75–4.51; P=0.0001) and BCHE K carriers (OR=3.31; 95% CI 1.82–6.02; P=0.0001).

Conclusions

The results of this meta-analysis indicate that BCHE K variant might be associated with AD risk.

Factors related to long-term post-stroke cognitive impairment in young adult ischemic stroke

BACKGROUND

Post-stroke cognitive impairment is common and a decisive prognostic factor. However, few studies have reported on post-stroke cognition in young adults, especially long-term cognition. This study was designed to investigate the influence of baseline factors, treatments, and functional outcome on the long-term cognitive outcome in young adults with ischemic stroke.

MATERIAL AND METHODS

Consecutive patients aged 18-45 years between January 1, 2006 and December 31, 2010, with a first-ever ischemic stroke, were recruited for cognitive assessment by telephone from December 10 to December 31, 2013 using modified versions of "Telephone Instrument for Cognitive Status" (TICS-m) scale. The relationship of cognitive impairment with baseline factors, treatments, and functional outcome were evaluated.

RESULTS

A total of 350 patients with an average age of 41.0±6.8 years (69.7% males and 30.3% females) were reviewed. The average follow-up period was 5.8±3.2 years, and cognitive impairment existed in 39.4% of patients at follow-up. Stroke severity on admission, functional outcome (modified Rankin Scale, mRS >2) at discharge, left anterior circulation syndrome, and stroke recurrence were markedly associated with post-stroke cognitive impairment (all P<0.01). Post-stroke cognition was also significantly related to mRS at follow-up (r=-0.563, P<0.001).

CONCLUSIONS

Post-stroke cognition was related to functional outcome: hence, treatment directed toward reducing functional disability might also reduce cognitive impairment.

Meta-analysis of Ubiquilin1 gene polymorphism and Alzheimer's disease risk

BACKGROUND

Some studies have evaluated the association between the Ubiquilin 1 (UBQLN1) gene UBQ-8i polymorphism and Alzheimer's disease (AD). However, the results remain uncertain. We carried out a meta-analysis to derive a more comprehensive estimation of this association.

MATERIAL/METHODS

Case-control studies were identified by searching databases of PubMed, EMBASE, Web of Science, CNKI, CBM, Wanfang, and VIP. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of the association.

RESULTS

The UBQ-8i polymorphism was significantly associated with an increased AD risk (OR=1.15; 95%CI 1.05-1.25; P=0.002). The combination of adjusted ORs also found UBQ-8i polymorphism was significantly associated with AD risk (OR=1.15; 95%CI 1.02-1.30; P=0.02). When stratified by APOE ε4 status, both APOE ε4 carriers and APOE non-ε4 carriers with UBQ-8i polymorphism had significantly increased AD risk (OR=1.28; 95%CI 1.05-1.56; P=0.01 and OR=1.25; 95%CI 1.04-1.50; P=0.02). In the subgroup analysis according to age, UBQ-8i polymorphism was significantly associated with LOAD risk (OR=1.17; 95%CI 1.05-1.31; P=0.005), but not with EOAD risk (OR=1.12; 95%CI 0.95-1.31; P=0.17).

CONCLUSIONS

These results suggest that the UBQ-8i polymorphism is associated with AD risk.

Omental transplantation for neurodegenerative diseases

Up to date, almost all researchers consider that there is still no effective therapy for neurodegenerative diseases (NDDs) and therefore, these diseases are incurable. However, since May 1998, we know that a progressive ischemia in the medial temporal lobes and subcommissural regions can cause Alzheimer's disease; because, in contrast to this, its revascularization by means of omental tissue can cure or improve this disease. Likewise we observed that the aging process, Huntington's disease, Parkinson's disease, and Amyotrophic lateral sclerosis; all of them are of ischemic origin caused by cerebral atherosclerosis, associated with vascular anomalies and/or environmental chemicals. On the contrary, an omental transplantation on the affected zone can stop and improve these diseases. For these reasons, I believe that NDDs, are wrongly classified as neurodegenerative disorders.

Glucose metabolism measured by positron emission tomography is reduced in patients with white matter presumably ischemic lesions

BACKGROUND

The severity and progression of white matter ischemic lesion (WMIL) are closely linked to vascular dementia. The function of neural tissue is closely linked to glucose consumption as the most important energy-supplying metabolic process. At present, [18]fluorine-fluorodeoxy glucose ([18]FDG) positron emission tomography (PET) can provide regional and 3-dimensional quantification of glucose metabolism in the human brain. Although MMSE and MoCA are commonly used screens in cognitive impairment, no research team has yet validated their performance in WMIL. The purpose of our study was to compare MMSE and MoCA in screening for cognitive impairment and to explore the correlations between CMRglu values and executive function.

MATERIAL AND METHODS

All the participants underwent comprehensive clinical, MoCA, MMSE, MRI, and PET examinations. Patients in the WMIL group were subdivided into 3 severity subgroups according to the Fazekas scale.

RESULTS

The MoCA scores were lower in the WMIL group. Our research indicates that MoCA is a more sensitive screening tool than the commonly used MMSE in detecting cognitive impairment in patients with WMIL. CMRglu values of gray matter were decreased in the WMIL group. Reductions of CMRglu in parietal lobe, frontal lobe, and white matter centrum semiovale were observed to different degrees in the WMIL groups according to the modified Fazekas scale. A significant negative correlation was found between executive function and CMRglu in the frontal lobe.

CONCLUSIONS

MoCA appears to be a more sensitive screening tool than the commonly used MMSE in detecting cognitive impairment in patients with WMIL. CMRglu can potentially be used as a biomarker for predicting the severity of WMIL.

Plasma cortisol in Alzheimer's disease with or without depressive symptoms

Background

Cortisol is presumed to be a risk factor for stress- and age-related disorders, such as depressive disorder and Alzheimer’s disease (AD). The aim of this study was to investigate the association of plasma cortisol concentration with AD in presence or absence of comorbid depressive symptoms.

Material/Methods

Plasma cortisol concentration was measured in 80 AD patients (35 of them with depressive symptoms), 27 elderly depressive patients without AD, and 37 elderly controls.

Results

Compared to controls, a significant increase of mean plasma cortisol was found in AD patients but not in depressive patients. Plasma cortisol was positively correlated with cognitive impairment in AD patients. We confirmed a U-shaped association between plasma cortisol and major depression and a linear association between plasma cortisol and AD without depressive symptoms. Significantly increased relative risk of disease in people with high plasma cortisol was found for AD with depressive symptoms and for AD with mild dementia.

Conclusions

Plasma cortisol reflects the degree of cognitive impairment in AD rather than the severity of comorbid depression. We confirmed that both hypercortisolemia and hypocortisolemia are associated with depressive disorder. Significant association between high plasma cortisol and AD was found, supporting the use of high plasma cortisol as a component of a panel of biochemical markers for AD with depressive symptoms as well as AD in the early stage of dementia development.