scholarly journals Increased hippocampal-inferior temporal cortex white matter connectivity following donepezil treatment in patients with mild cognitive impairment: A diffusion tensor probabilistic tractography study

2021 ◽  
Author(s):  
Gwang-Won Kim ◽  
Kwangsung Park ◽  
Gwang-Woo Jeong
Keyword(s):  
Cognitive Impairment ◽  
Mild Cognitive Impairment ◽  
White Matter ◽  
Diffusion Tensor ◽  
Early Stage ◽  
Structural Connectivity ◽  
Temporal Cortex ◽  
Mean Diffusivity ◽  
Inferior Temporal Cortex ◽  
Probabilistic Tractography

Abstract The incidence of Alzheimer’s disease (AD) has been increasing each year; however, few methods are available to identify the effects of treatment for AD. Defective hippocampus has been associated with mild cognitive impairment (MCI), an early stage of AD. However, the effect of donepezil treatment on hippocampus-related networks is unknown. The purpose of this study was to evaluate the hippocampal white matter (WM) connectivity following donepezil treatment in patients with MCI using probabilistic tractography, and to further determine the WM integrity and changes in brain volume. Magnetic resonance imaging and diffusion tensor imaging (DTI) data of patients with MCI before and after 6-month donepezil treatment were acquired. Volumes and DTI scalars of 11 regions of interest comprising the frontal and temporal cortices and subcortical regions were measured. Seed-based structural connectivity analyses were focused on the hippocampus. Compared with healthy controls, patients with MCI showed significantly decreased hippocampal volume and WM connectivity with the superior frontal gyrus, as well as increased mean diffusivity (MD) and radial diffusivity (RD) in the amygdala (p < 0.05, Bonferroni-corrected). After six months of donepezil treatment, patients with MCI showed increased hippocampal-inferior temporal gyrus (ITG) WM connectivity (p < 0.05, Bonferroni-corrected), which was normalized to the healthy control. These findings will be useful in developing theories to describe the etiology of MCI and the therapeutic role of anticholinesterases.

Olfactory Function and Diffusion Tensor Imaging as Markers of Mild Cognitive Impairment in Early Stages of Parkinson's Disease

2021 ◽  
pp. 155005942110582
Author(s):  
Sophie A. Stewart ◽  
Laura Pimer ◽  
John D. Fisk ◽  
Benjamin Rusak ◽  
Ron A. Leslie ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Cognitive Impairment ◽  
Diffusion Tensor Imaging ◽  
Mild Cognitive Impairment ◽  
White Matter ◽  
Neurodegenerative Disorder ◽  
Diffusion Tensor ◽  
Early Stage ◽  
White Matter Integrity

Parkinson's disease (PD) is a neurodegenerative disorder that is typified by motor signs and symptoms but can also lead to significant cognitive impairment and dementia Parkinson's Disease Dementia (PDD). While dementia is considered a nonmotor feature of PD that typically occurs later, individuals with PD may experience mild cognitive impairment (PD-MCI) earlier in the disease course. Olfactory deficit (OD) is considered another nonmotor symptom of PD and often presents even before the motor signs and diagnosis of PD. We examined potential links among cognitive impairment, olfactory functioning, and white matter integrity of olfactory brain regions in persons with early-stage PD. Cognitive tests were used to established groups with PD-MCI and with normal cognition (PD-NC). Olfactory functioning was examined using the University of Pennsylvania Smell Identification Test (UPSIT) while the white matter integrity of the anterior olfactory structures (AOS) was examined using magnetic resonance imaging (MRI) diffusion tensor imaging (DTI) analysis. Those with PD-MCI demonstrated poorer olfactory functioning and abnormalities based on all DTI parameters in the AOS, relative to PD-NC individuals. OD and microstructural changes in the AOS of individuals with PD may serve as additional biological markers of PD-MCI.

Deep microbleeds and periventricular white matter disintegrity are independent predictors of attention/executive dysfunction in non-dementia patients with small vessel disease

2016 ◽  
Vol 29 (5) ◽  
pp. 793-803 ◽  
Author(s):  
Wen-wei Cao ◽  
Yao Wang ◽  
Quan Dong ◽  
Xue Chen ◽  
Yan-sheng Li ◽  
...  
Keyword(s):  
Cognitive Impairment ◽  
White Matter ◽  
Diffusion Tensor ◽  
Small Vessel Disease ◽  
Early Stage ◽  
Mean Diffusivity ◽  
Executive Dysfunction ◽  
Small Vessel ◽  
Periventricular White Matter ◽  
Vessel Disease

ABSTRACTBackground:Cerebral small vessel disease (SVD) is the common cause of cognitive decline in the old population. MRI can be used to clarify its mechanisms. However, the surrogate markers of MRI for early cognitive impairment in SVD remain uncertain to date. We investigated the cognitive impacts of cerebral microbleeds (CMBs), diffusion tensor imaging (DTI), and brain volumetric measurements in a cohort of post-stroke non-dementia SVD patients.Methods:Fifty five non-dementia SVD patients were consecutively recruited and categorized into two groups as no cognitive impairment (NCI) (n = 23) or vascular mild cognitive impairment (VaMCI) (n = 32). Detailed neuropsychological assessment and multimodal MRI were completed.Results:The two groups differed significantly on Z scores of all cognitive domains (all p < 0.01) except for the language. There were more patients with hypertension (p = 0.038) or depression (p = 0.019) in the VaMCI than those in the NCI group. Multiple regression analysis of cognition showed periventricular mean diffusivity (MD) (β = −0.457, p < 0.01) and deep CMBs numbers (β = −0.352, p < 0.01) as the predictors of attention/executive function, which explained 45.2% of the total variance. Periventricular MD was the independent predictor for either memory (β = −0.314, p < 0.05) or visuo-spatial function (β = −0.375, p < 0.01); however, only small proportion of variance could be accounted for (9.8% and 12.4%, respectively). Language was not found to be correlated with any of the MRI parameters. No correlation was found between brain atrophic indices and any of the cognitive measures.Conclusion:Arteriosclerotic CMBs and periventricular white matter disintegrity seem to be independent MRI surrogated markers in the early stage of cognitive impairment in SVD.

scholarly journals Disrupted white matter integrity is associated with cognitive deficits in patients with amnestic mild cognitive impairment: An atlas-based study

2016 ◽  
Vol 4 ◽  
pp. 205031211664881 ◽  
Author(s):  
Duan Liu ◽  
Zan Wang ◽  
Hao Shu ◽  
Zhijun Zhang
Keyword(s):  
Cognitive Impairment ◽  
Diffusion Tensor Imaging ◽  
Mild Cognitive Impairment ◽  
White Matter ◽  
Diffusion Tensor ◽  
Mean Diffusivity ◽  
Amnestic Mild Cognitive Impairment ◽  
Uncinate Fasciculus ◽  
Radial Diffusivity ◽  
Mild Cognitive Impairment Group

Objective: This study investigated white matter integrity in patients with amnestic mild cognitive impairment by diffusion tensor imaging. Methods: A total of 83 patients with amnestic mild cognitive impairment and 85 elderly healthy controls underwent neuropsychological testing and a diffusion tensor imaging scan. Whole-brain white matter data were parcellated into 50 regions based on the anatomical ICBM-DTI-81 atlas, and regional diffusion metrics consisting of fractional anisotropy, mean diffusivity, radial diffusivity, and axial diffusivity were calculated for each region. Diffusion tensor imaging indices were compared between groups, and it was determined that between-group differences were significantly correlated with neurocognitive performance. Results: Relative to the healthy controls group, the amnestic mild cognitive impairment group exhibited poorer cognitive performance in all neuropsychological tests except the complex figure test ( p = 0.083) and showed decreased mean fractional anisotropy in the fornix, increased mean diffusivity in the fornix and bilateral uncinate fasciculus, elevated axial diffusivity in the fornix and genu of corpus callosum, and elevated radial diffusivity in the fornix and bilateral uncinate fasciculus ( p < 0.05). Behaviorally, integrity of the bilateral uncinate fasciculus was correlated positively with episodic memory function, while left uncinate fasciculus integrity was positively associated with language function in the amnestic mild cognitive impairment group ( p < 0.05). Conclusion: White matter abnormalities in neural pathways associated with memory were correlated with neurocognitive deficiencies in amnestic mild cognitive impairment. Given that amnestic mild cognitive impairment is putatively a prodromal syndrome for Alzheimer’s disease, this study furthers our understanding of the white matter changes associated with Alzheimer’s disease pathogenesis in the predementia stage.

scholarly journals Changes in Parahippocampal White Matter Integrity in Amnestic Mild Cognitive Impairment: A Diffusion Tensor Imaging Study

2009 ◽  
Vol 21 (1-2) ◽  
pp. 51-61 ◽  
Author(s):  
E. J. Rogalski ◽  
C. M. Murphy ◽  
L. deToledo-Morrell ◽  
R. C. Shah ◽  
M. E. Moseley ◽  
...  
Keyword(s):  
Cognitive Impairment ◽  
Diffusion Tensor Imaging ◽  
Mild Cognitive Impairment ◽  
White Matter ◽  
Diffusion Tensor ◽  
Mean Diffusivity ◽  
Amnestic Mild Cognitive Impairment ◽  
Perforant Path ◽  
Tissue Loss

In the present study, changes in the parahippocampal white matter (PWM), in the region that includes the perforant path, were investigated, in vivo, in 14 individuals with amnestic mild cognitive impairment (aMCI) compared to 14 elderly controls with no cognitive impairment (NCI). For this purpose, (1) volumetry; (2) diffusion tensor imaging (DTI) derived measures of mean diffusivity (MD) and fractional anisotropy (FA); and (3) tractography were used. In addition, regression models were utilized to examine the association of PWM measurements with memory decline. The results from this study confirm previous findings in our laboratory and others, showing that compared to controls, individuals with aMCI have PWM volume loss. In addition to volume reduction, participants with aMCI demonstrated a significant increase in MD, but no difference in FA, both in the PWM region and in fibers modeled to pass through the PWM region. Further, the DTI metric of MD was associated with declarative memory performance, suggesting it may be a sensitive marker for memory dysfunction. These results indicate that there is general tissue loss and degradation (decreased volume; increased MD) in individuals with aMCI compared to older people with normal cognitive function. However, the microstructural organization of remaining fibers, as determined by measures of anisotropic diffusion, is not significantly different from that of controls.

Abstract WP489: Disrupted Functional and Structural Connectivity Within Default Mode Network Contribute to WMH Related Cognitive Impairment

Stroke ◽  
2020 ◽  
Vol 51 (Suppl_1) ◽  
Author(s):  
Lili Huang ◽  
Qing Ye ◽  
Xin Chen ◽  
Dan Yang ◽  
Ruomeng Qin ◽  
...  
Keyword(s):  
Risk Factors ◽  
Cognitive Impairment ◽  
White Matter ◽  
Default Mode Network ◽  
Rating Scale ◽  
Diffusion Tensor ◽  
Structural Connectivity ◽  
Mean Diffusivity ◽  
White Matter Tracts ◽  
Default Mode

Aims: The prevalence of white matter hyperintensities (WMH) rises dramatically with aging. Both the progression of WMH and default mode network (DMN) have been proven to be closely associated with cognitive function. Thus, we hypothesized that changes in functional connectivity (FC) and structural connectivity (SC) of the DMN contributed to WMH related cognitive impairment. Methods: A total of 116 subjects were enrolled from the Cerebral Small Vessel Disease Register in Drum Tower Hospital of Nanjing University, and were distributed across three categories according to Fazekas rating scale: WMH I(n=57), WMH II(n=34), and WMH III (n=25). The clinical and neuropsychological data were collected, and all participants underwent 3D T1 weighted images, T2 weighted images, 3D fluid attenuated inversion recovery (FLAIR) images, diffusion tensor images (DTI), and diffusion weighted imaging (DWI). The alterations of FC and SC within the DMN were further explored in these subjects. Results: The study found that age and hypertension were risk factors for WMH progression. Subjects with a larger WMH burden displayed higher DMN FC in the medial frontal gyrus (MFG), while lower DMN FC in the thalamus. After adjustment for age, gender, and education, the increasing FC between the MFG, posterior cingulate cortex (PCC), and ascending mean diffusivity (MD) of the white matter tracts between the hippocampus and PCC were independent indicators of worse performance in memory. Moreover, the decreasing FC between the thalamus, PCC, and ascending MD of the white matter tracts between the thalamus and PCC were independent risk factors for a slower processing speed. Conclusion: The changes in FC and SC within the DMN attributed to WMH progression were responsible for the cognitive impairment.

scholarly journals Thalamic Structural Connectivity Abnormalities in Minimal Hepatic Encephalopathy

2021 ◽  
Vol 15 ◽  
Author(s):  
Hua-Jun Chen ◽  
Xiao-Hong Zhang ◽  
Jia-Yan Shi ◽  
Shao-Fan Jiang ◽  
Yi-Fan Sun ◽  
...  
Keyword(s):  
Hepatic Encephalopathy ◽  
White Matter ◽  
Diffusion Tensor ◽  
Structural Connectivity ◽  
Mean Diffusivity ◽  
Minimal Hepatic Encephalopathy ◽  
Probabilistic Tractography ◽  
Neurocognitive Performance ◽  
Cirrhotic Patients ◽  
Subcortical Regions

Background and Aims: Numerous studies have demonstrated thalamus-related structural, functional, and metabolic abnormalities in minimal hepatic encephalopathy (MHE). We conducted the first study to investigate thalamic structural connectivity alterations in MHE.MethodsDiffusion tensor imaging (DTI)-based probabilistic tractography was employed to determine the structural linkage between the thalamus and cortical/subcortical regions in 52 cirrhotic patients [22 with MHE; 30 without MHE (NHE)] and 30 controls. We measured these thalamic connections, which included connectivity strength (CS), fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD), and then compared these among the three groups. Neurocognitive assessment was also performed. Correlation analysis was conducted to investigate the relationship between neurocognitive performance and the above measurements. Classification analysis was performed to determine whether thalamic connection measurements can distinguish MHE from NHE.ResultsThe probabilistic tractography revealed thalamic structural connections, which were disrupted in cirrhotic patients (as reflected by a decrease in CS/FA and an increase in MD/AD/RD). Abnormal thalamic connections primarily involved the prefrontal cortex, sensorimotor cortex, parietal cortex, medial temporal cortex and hippocampus, and striatum. Thalamic connectivity abnormalities deteriorated from NHE to MHE, and they were correlated with patients’ neurocognitive performance. The moderate classification accuracy was obtained using CS and MD as discriminating indexes.ConclusionOur results demonstrated the altered thalamic structural connectivity involving both cortical and subcortical regions in MHE, which could be regarded as representative of MHE-related widespread impairments in white matter pathways. The disturbed thalamic connectivity may underlie the mechanism of cognitive deficits in MHE and may potentially be utilized as a biomarker for diagnosing MHE and in monitoring disease progression. In addition to thalamic–cortical/subcortical connections, further studies are recommended to explore the structural alterations in other white matter pathways in MHE.

Assessment of White Matter Lesions in Parkinson's Disease: Voxel-based Analysis and Tract-based Spatial Statistics Analysis of Parkinson's Disease with Mild Cognitive Impairment

2020 ◽  
Vol 17 (4) ◽  
pp. 480-486
Author(s):  
Wei Pu ◽  
Xudong Shen ◽  
Mingming Huang ◽  
Zhiqian Li ◽  
Xianchun Zeng ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Cognitive Impairment ◽  
Mild Cognitive Impairment ◽  
White Matter ◽  
Corpus Callosum ◽  
Fractional Anisotropy ◽  
Spatial Statistics ◽  
Diffusion Tensor ◽  
Tract Based Spatial Statistics

Objective: Application of diffusion tensor imaging (DTI) to explore the changes of FA value in patients with Parkinson's disease (PD) with mild cognitive impairment. Methods: 27 patients with PD were divided into PD with mild cognitive impairment (PD-MCI) group (n = 7) and PD group (n = 20). The original images were processed using voxel-based analysis (VBA) and tract-based spatial statistics (TBSS). Results: The average age of pd-mci group was longer than that of PD group, and the course of disease was longer than that of PD group. Compared with PD group, the voxel based analysis-fractional anisotropy (VBA-FA) values of PD-MCI group decreased in the following areas: bilateral frontal lobe, bilateral temporal lobe, bilateral parietal lobe, bilateral subthalamic nucleus, corpus callosum, and gyrus cingula. Tract-based spatial statistics-fractional anisotropy (TBSS-FA) values in PD-MCI group decreased in bilateral corticospinal tract, anterior cingulum, posterior cingulum, fornix tract, bilateral superior thalamic radiation, corpus callosum(genu, body and splenium), bilateral uncinate fasciculus, bilateral inferior longitudinal fasciculus, bilateral superior longitudinal fasciculus, bilateral superior fronto-occipital fasciculus, bilateral inferior fronto-occipital fasciculus, and bilateral parietal-occipital tracts. The mean age of onset in the PD-MCI group was greater than that in the PD group, and the disease course was longer than that in the PD group. Conclusion: DTI-based VBA and TBSS post-processing methods can detect abnormalities in multiple brain areas and white matter fiber tracts in PD-MCI patients. Impairment of multiple cerebral cortex and white matter fiber pathways may be an important causes of cognitive dysfunction in PD-MCI.

scholarly journals White matter abnormalities in the corpus callosum with cognitive impairment in Parkinson disease

Neurology ◽  
2018 ◽  
Vol 91 (24) ◽  
pp. e2244-e2255 ◽  
Author(s):  
Ian O. Bledsoe ◽  
Glenn T. Stebbins ◽  
Doug Merkitch ◽  
Jennifer G. Goldman
Keyword(s):  
Cognitive Impairment ◽  
White Matter ◽  
Corpus Callosum ◽  
Parkinson Disease ◽  
Information Transfer ◽  
Diffusion Tensor ◽  
Anterior Segment ◽  
Mean Diffusivity ◽  
Cognitive Domain ◽  
White Matter Abnormalities

ObjectiveTo evaluate microstructural characteristics of the corpus callosum using diffusion tensor imaging (DTI) and their relationships to cognitive impairment in Parkinson disease (PD).MethodsSeventy-five participants with PD and 24 healthy control (HC) participants underwent structural MRI brain scans including DTI sequences and clinical and neuropsychological evaluations. Using Movement Disorder Society criteria, PD participants were classified as having normal cognition (PD-NC, n = 23), mild cognitive impairment (PD-MCI, n = 35), or dementia (PDD, n = 17). Cognitive domain (attention/working memory, executive function, language, memory, visuospatial function) z scores were calculated. DTI scalar values, including fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD), were established for 5 callosal segments on a midsagittal plane, single slice using a topographically derived parcellation method. Scalar values were compared among participant groups. Regression analyses were performed on cognitive domain z scores and DTI metrics.ResultsParticipants with PD showed increased AD values in the anterior 3 callosal segments compared to healthy controls. Participants with PDD had significantly increased AD, MD, and RD in the anterior 2 segments compared to participants with PD-NC and most anterior segment compared to participants with PD-MCI. FA values did not differ significantly between participants with PD and participants with HC or among PD cognitive groups. The strongest associations for the DTI metrics and cognitive performance occurred in the most anterior and most posterior callosal segments, and also reflected fronto-striatal and posterior cortical type cognitive deficits, respectively.ConclusionsMicrostructural white matter abnormalities of the corpus callosum, as measured by DTI, may contribute to PD cognitive impairment by disrupting information transfer across interhemispheric and callosal–cortical projections.

scholarly journals Motor cortex gliomas induces microstructural changes of large fiber tracts revealed by TBSS

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Xiangdong Wang ◽  
Chunyao Zhou ◽  
Lei Wang ◽  
Yinyan Wang ◽  
Tao Jiang
Keyword(s):  
White Matter ◽  
Motor Cortex ◽  
Diffusion Tensor ◽  
Early Stage ◽  
Mean Diffusivity ◽  
Cerebral White Matter ◽  
Control Group ◽  
Fiber Tracts ◽  
3.0 T ◽  
White Matter Fiber Tracts

Abstract Gliomas grow and invade along white matter fiber tracts. This study assessed the effects of motor cortex gliomas on the cerebral white matter fiber bundle skeleton. The motor cortex glioma group included 21 patients, and the control group comprised 14 healthy volunteers. Both groups underwent magnetic resonance imaging-based 3.0 T diffusion tensor imaging. We used tract-based spatial statistics to analyze the characteristics of white matter fiber bundles. The left and right motor cortex glioma groups were analyzed separately from the control group. Results were statistically corrected by the family-wise error rate. Compared with the controls, patients with left motor cortex gliomas exhibited significantly reduced fractional anisotropy and an increased radial diffusivity in the corpus callosum. The alterations in mean diffusivity (MD) and the axial diffusivity (AD) were widely distributed throughout the brain. Furthermore, atlas-based analysis showed elevated MD and AD in the contralateral superior fronto-occipital fasciculus. Motor cortex gliomas significantly affect white matter fiber microstructure proximal to the tumor. The range of affected white matter fibers may extend beyond the tumor-affected area. These changes are primarily related to early stage tumor invasion.

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