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1.
Postgrad Med ; 131(7): 533-538, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31478419

RESUMO

Introduction: Depression in patients with mild cognitive impairment (MCI) and dementia of the Alzheimer's type (AD) is associated with worse prognosis. Indeed, depressed MCI patients have worse cognitive performance and greater loss of gray-matter volume in several brain areas. To date, knowledge of the factors that can mitigate this detrimental effect is still limited. The aim of the present study was to understand in what way cognitive reserve/brain reserve and depression interact and are linked to regional atrophy in early stage AD. Methods: Depression was evaluated with the Patient Health Questionnaire-9 in 90 patients with early AD, and a cutoff of ≥ 5 was used to separate depressed (n = 44) from non-depressed (n = 46) patients. Each group was further stratified into high/low cognitive reserve/brain reserve. Cognitive reserve was calculated using years of education as proxy, while normalized parenchymal volumes were used to estimate brain reserve. Voxel-based morphometry was carried out to extract and analyze gray-matter maps. 2 × 2 ANCOVAs were run to test the effect of the reserve-by-depression interaction on gray matter. Age and hippocampal ratio were used as covariates. Composite indices of major cognitive domains were also analyzed with comparable models. Results: No reserve-by-depression interaction was found in the analytical models of gray matter. Depression was associated with less gray matter volume in the cerebellum and parahippocampal gyrus. The brain reserve-by-depression interaction was a significant predictor of executive functioning. Among those with high brain reserve, depressed patients had poorer executive skills. No significant results were found in association with cognitive reserve. Conclusion: These findings suggest that brain reserve may modulate the association between neurodegeneration and depression in patients with MCI and dementia of the AD type, influencing in particular executive functioning.


Assuntos
Doença de Alzheimer/psicologia , Disfunção Cognitiva/psicologia , Reserva Cognitiva , Depressão/psicologia , Substância Cinzenta/diagnóstico por imagem , Idoso , Doença de Alzheimer/diagnóstico por imagem , Doença de Alzheimer/fisiopatologia , Atrofia , Encéfalo/diagnóstico por imagem , Encéfalo/patologia , Cerebelo/diagnóstico por imagem , Cerebelo/patologia , Disfunção Cognitiva/diagnóstico por imagem , Disfunção Cognitiva/fisiopatologia , Depressão/diagnóstico por imagem , Depressão/fisiopatologia , Feminino , Substância Cinzenta/patologia , Hipocampo/diagnóstico por imagem , Hipocampo/patologia , Humanos , Masculino , Pessoa de Meia-Idade , Tamanho do Órgão , Giro Para-Hipocampal/diagnóstico por imagem , Giro Para-Hipocampal/patologia , Questionário de Saúde do Paciente
2.
Postgrad Med ; 131(7): 509-522, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31422718

RESUMO

Objectives: Visual hallucinations (VH) are common in Lewy body disease (LBD), and have been associated with cognitive and structural brain alterations. Evidence so far concerns mainly Parkinson's disease (PD), but little is known about symptom-specific pathophysiological mechanisms across the LBD spectrum, especially related to the presence of dementia. The aim of the present pilot study was to investigate the neuroanatomical, and neuropsychological characteristics related to VH in two forms of LBD, namely dementia with Lewy bodies (DLB) and PD without dementia. Methods: Whole brain voxel-based morphometry (VBM) analyses on 3D MRI acquired structural brain scans, and neuropsychological testing were performed on 28 clinically diagnosed DLB (11 with VH, 17 NVH), and 24 PD (9 with VH, and 15 NVH) patients. In order to assess differences in gray matter (GM) regional volumes, and cognitive performance, hallucinating patients for each group were compared with corresponding non-hallucinating ones. Results: DLB patients with VH presented significantly worse visual attention deficits compared to those without, which persisted even when controlling for visual perception. Whole brain VBM analysis revealed decreased GM volume in DLB with VH in the right superior and medial frontal gyri, putamen, caudate nucleus and insula. Subcortical regional volumes were also significantly associated with visual attention performance. Hallucinating PD patients, instead, presented more severe executive dysfunction, but VBM showed no volumetric differences between the two PD subgroups. Post hoc region of interest analyses revealed striatal GM loss in PD with VH. Conclusion: Frontal and striatal GM atrophy may contribute to the emergence of VH in DLB, which may be fostered by the more severe attention deficits. Striatal GM loss and executive dysfunction, instead, appeared to underlie VH in PD without dementia.


Assuntos
Núcleo Caudado/diagnóstico por imagem , Lobo Frontal/diagnóstico por imagem , Substância Cinzenta/diagnóstico por imagem , Alucinações/diagnóstico por imagem , Doença por Corpos de Lewy/diagnóstico por imagem , Doença de Parkinson/diagnóstico por imagem , Putamen/diagnóstico por imagem , Idoso , Idoso de 80 Anos ou mais , Atenção , Estudos de Casos e Controles , Núcleo Caudado/patologia , Córtex Cerebral/diagnóstico por imagem , Córtex Cerebral/patologia , Feminino , Lobo Frontal/patologia , Substância Cinzenta/patologia , Alucinações/psicologia , Humanos , Doença por Corpos de Lewy/psicologia , Imagem por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos , Tamanho do Órgão , Doença de Parkinson/psicologia , Putamen/patologia , Percepção Visual
3.
JAMA ; 322(4): 336-347, 2019 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-31334794

RESUMO

Importance: United States government personnel experienced potential exposures to uncharacterized directional phenomena while serving in Havana, Cuba, from late 2016 through May 2018. The underlying neuroanatomical findings have not been described. Objective: To examine potential differences in brain tissue volume, microstructure, and functional connectivity in government personnel compared with individuals not exposed to directional phenomena. Design, Setting, and Participants: Forty government personnel (patients) who were potentially exposed and experienced neurological symptoms underwent evaluation at a US academic medical center from August 21, 2017, to June 8, 2018, including advanced structural and functional magnetic resonance imaging analytics. Findings were compared with imaging findings of 48 demographically similar healthy controls. Exposures: Potential exposure to uncharacterized directional phenomena of unknown etiology, manifesting as pressure, vibration, or sound. Main Outcomes and Measures: Potential imaging-based differences between patients and controls with regard to (1) white matter and gray matter total and regional brain volumes, (2) cerebellar tissue microstructure metrics (eg, mean diffusivity), and (3) functional connectivity in the visuospatial, auditory, and executive control subnetworks. Results: Imaging studies were completed for 40 patients (mean age, 40.4 years; 23 [57.5%] men; imaging performed a median of 188 [range, 4-403] days after initial exposure) and 48 controls (mean age, 37.6 years; 33 [68.8%] men). Mean whole brain white matter volume was significantly smaller in patients compared with controls (patients: 542.22 cm3; controls: 569.61 cm3; difference, -27.39 [95% CI, -37.93 to -16.84] cm3; P < .001), with no significant difference in the whole brain gray matter volume (patients: 698.55 cm3; controls: 691.83 cm3; difference, 6.72 [95% CI, -4.83 to 18.27] cm3; P = .25). Among patients compared with controls, there were significantly greater ventral diencephalon and cerebellar gray matter volumes and significantly smaller frontal, occipital, and parietal lobe white matter volumes; significantly lower mean diffusivity in the inferior vermis of the cerebellum (patients: 7.71 × 10-4 mm2/s; controls: 8.98 × 10-4 mm2/s; difference, -1.27 × 10-4 [95% CI, -1.93 × 10-4 to -6.17 × 10-5] mm2/s; P < .001); and significantly lower mean functional connectivity in the auditory subnetwork (patients: 0.45; controls: 0.61; difference, -0.16 [95% CI, -0.26 to -0.05]; P = .003) and visuospatial subnetwork (patients: 0.30; controls: 0.40; difference, -0.10 [95% CI, -0.16 to -0.04]; P = .002) but not in the executive control subnetwork (patients: 0.24; controls: 0.25; difference: -0.016 [95% CI, -0.04 to 0.01]; P = .23). Conclusions and Relevance: Among US government personnel in Havana, Cuba, with potential exposure to directional phenomena, compared with healthy controls, advanced brain magnetic resonance imaging revealed significant differences in whole brain white matter volume, regional gray and white matter volumes, cerebellar tissue microstructural integrity, and functional connectivity in the auditory and visuospatial subnetworks but not in the executive control subnetwork. The clinical importance of these differences is uncertain and may require further study.


Assuntos
Encéfalo/patologia , Empregados do Governo , Doenças do Sistema Nervoso/diagnóstico por imagem , Adulto , Encéfalo/anatomia & histologia , Encéfalo/diagnóstico por imagem , Estudos de Casos e Controles , Cuba , Imagem de Difusão por Ressonância Magnética , Feminino , Substância Cinzenta/anatomia & histologia , Substância Cinzenta/diagnóstico por imagem , Humanos , Imagem por Ressonância Magnética , Masculino , Doenças do Sistema Nervoso/etiologia , Ruído/efeitos adversos , Tamanho do Órgão , Valores de Referência , Estados Unidos , Substância Branca/anatomia & histologia , Substância Branca/diagnóstico por imagem
4.
Neuroradiology ; 61(6): 695-702, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30949745

RESUMO

PURPOSE: Previous studies have focused on global cerebral alterations observed in cirrhosis. However, little was known about the specific abnormalities of vision-related brain regions in cirrhotic patients. In this study, we sought to explore neurological alterations of vision-related regions by measuring brain resting-state network connectivity, based on the structural investigation in cirrhotic patients without clinical sign of hepatic encephalopathy (HE). METHODS: Structural and functional magnetic resonance image (MRI) data were collected from 20 hepatitis B virus (HBV)-related cirrhotic patients without clinical sign of HE and from 20 healthy controls (HC). Voxel-based morphometric (VBM) analysis and brain functional network analysis were performed to detect abnormalities in cerebral structure and function. RESULTS: Cirrhotic patients showed regions with the most significant gray matter reduction primarily in vision-related brain regions, including the bilateral lingual gyri, left putamen, right fusiform gyrus, and right calcarine gyrus, and other significant gray matter reductions were distributed in bilateral hippocampus. Based on structural investigation focused on vision-related regions, brain functional network analysis revealed decreased functional connectivity between brain functional networks within vision-related regions (primary visual network (PVN), higher visual network (HVN), visuospatial network (VSN)) in the patient group compared with HC group. CONCLUSION: These results indicate that structural and functional impairment were evident in the vision-related brain regions in cirrhotic patients without clinical sign of hepatic encephalopathy. The physiopathology and clinical relevance of these changes could not be ascertained from the present study, which provided a basis for further evolution of the disease.


Assuntos
Substância Cinzenta/diagnóstico por imagem , Encefalopatia Hepática/diagnóstico , Imagem por Ressonância Magnética/métodos , Córtex Visual/diagnóstico por imagem , Estudos de Casos e Controles , Feminino , Substância Cinzenta/patologia , Encefalopatia Hepática/virologia , Humanos , Masculino , Pessoa de Meia-Idade , Córtex Visual/patologia
5.
Maturitas ; 123: 45-54, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31027677

RESUMO

BACKGROUND: Motoric cognitive risk syndrome (MCR) is a pre-dementia stage, which associates slow walking speed with subjective cognitive impairment (SCI). MCR's clinical utility for the prediction of dementia and its pathophysiology are unclear. The aim of this systematic review and meta-analysis is to examine the association of MCR with incident cognitive impairment, cognitive performance and brain structures. METHODS: A systematic search was conducted using the Medical Subject Heading terms "Walking" and "Cognition disorders" combined with the terms "Subjective cognitive impairment", "Subjective cognitive decline" and "Motoric cognitive risk". A total of 11 studies were included in the systematic review and meta-analysis: 3 studies had dementia as the outcome, 3 studies had cognitive performance as the outcome, 4 studies had brain structures as the outcome and one study examined the incidence of both major neurocognitive disorders and cognitive impairment. RESULTS: MCR was found to be associated with incident cognitive impairment (pooled hazard ratio (HR) = 1.70, 95% CI, 1.46-1.98 with P-value <0.001) and dementia (pooled HR = 2.50, 95% CI, 1.75-2.39 with P-value <0.001). MCR was also found to be associated with low grey matter volume involving the premotor and the prefrontal cortex, and lacunar lesions in the frontal lobe. No significant association was found with white matter abnormalities. CONCLUSION: MCR predicts cognitive impairment and dementia, suggesting that it may be used as a screening syndrome for dementia in a primary care setting. Its significant association with both low grey matter volume and lacunar lesions makes its pathophysiology unclear and suggests multiple pathways.


Assuntos
Encéfalo/diagnóstico por imagem , Disfunção Cognitiva/epidemiologia , Demência/epidemiologia , Sintomas Prodrômicos , Velocidade de Caminhada , Encéfalo/patologia , Cognição/fisiologia , Transtornos Cognitivos/epidemiologia , Disfunção Cognitiva/diagnóstico por imagem , Autoavaliação Diagnóstica , Substância Cinzenta/diagnóstico por imagem , Substância Cinzenta/patologia , Humanos , Incidência , Testes Neuropsicológicos , Tamanho do Órgão , Modelos de Riscos Proporcionais , Fatores de Risco , Síndrome
6.
Brain Topogr ; 32(3): 504-518, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30949863

RESUMO

Motor functions are frequently impaired in Asperger syndrome (AS). In this study, we examined the motor cortex structure and function using navigated transcranial magnetic stimulation (nTMS) and voxel-based morphometry (VBM) and correlated the results with the box and block test (BBT) of manual dexterity and physical activity in eight boys with AS, aged 8-11 years, and their matched controls. With nTMS, we found less focused cortical representation areas of distinct hand muscles in AS. There was hemispheric asymmetry in the motor maps, silent period duration and active MEP latency in the AS group, but not in controls. Exploratory VBM analysis revealed less gray matter in the left postcentral gyrus, especially in the face area, and less white matter in the precentral area in AS as compared to controls. On the contrary, in the right leg area, subjects with AS displayed an increased density of gray matter. The structural findings of the left hemisphere correlated negatively with BBT score in controls, whereas the structure of the right hemisphere in the AS group correlated positively with motor function as assessed by BBT. These preliminary functional (neurophysiological and behavioral) findings are indicative of asymmetry, and co-existing structural alterations may reflect the motor impairments causing the deteriorations in manual dexterity and other motor functions commonly encountered in children with AS.


Assuntos
Síndrome de Asperger/diagnóstico por imagem , Córtex Motor/diagnóstico por imagem , Síndrome de Asperger/fisiopatologia , Encéfalo/diagnóstico por imagem , Encéfalo/fisiopatologia , Mapeamento Encefálico/métodos , Criança , Potencial Evocado Motor/fisiologia , Exercício , Face , Lateralidade Funcional , Substância Cinzenta/diagnóstico por imagem , Mãos , Humanos , Imagem por Ressonância Magnética , Masculino , Córtex Motor/fisiopatologia , Músculo Esquelético , Córtex Somatossensorial/diagnóstico por imagem , Córtex Somatossensorial/fisiopatologia , Estimulação Magnética Transcraniana/métodos , Substância Branca/diagnóstico por imagem
7.
J Med Syst ; 43(5): 131, 2019 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-30937597

RESUMO

In order to study the application of multi-modal magnetic resonance imaging (MRI) fusion technology in schizophrenia, a 4-way multi-modal fusion method based on mCCA+jICA is used to fuse the local consistency and functional network connection of resting-state functional MRI, gray matter volume of structural MRI, and partial anisotropy of diffusion MRI four characteristics of large sample of schizophrenic patients in multi-site China, trying to find out the common characteristics of function and structure of significant differences between schizophrenia and healthy controls. It is found that compared with normal people, schizophrenic patients show higher local consistency, lower gray matter volume, lower functional network connectivity and decreased white matter integrity in the anterior thalamic radiation, upper bundle and other bundles in brain areas such as basal ganglia network, hippocampus and prominence network. There is a significant correlation between a thalamocortical perceptual loop and auditory hallucination in schizophrenia, and there is a high degree of spatial consistency and commonality among the three MRI features. The higher the volume of gray matter in the dorsolateral and medial prefrontal cortex is, the higher the integrity of white matter fibers such as corticospinal tract, superior longitudinal tract and anterior thalamic radiation is, the higher the digital backward score is, and the better the working memory ability of the subjects is.


Assuntos
Encéfalo/patologia , Processamento de Imagem Assistida por Computador/métodos , Imagem por Ressonância Magnética/métodos , Esquizofrenia/patologia , Adolescente , Adulto , Anisotropia , Encéfalo/diagnóstico por imagem , China , Imagem de Difusão por Ressonância Magnética , Feminino , Substância Cinzenta/diagnóstico por imagem , Substância Cinzenta/patologia , Alucinações , Humanos , Masculino , Pessoa de Meia-Idade , Esquizofrenia/diagnóstico por imagem , Substância Branca/diagnóstico por imagem , Substância Branca/patologia , Adulto Jovem
8.
BMC Med Imaging ; 19(1): 26, 2019 04 03.
Artigo em Inglês | MEDLINE | ID: mdl-30943911

RESUMO

BACKGROUND: Initial reports of 23Na magnetic resonance imaging (MRI) date back to the 1970s. However, methodological challenges of the technique hampered its widespread adoption for many years. Recent technical developments have overcome some of these limitations and have led to more optimal conditions for 23Na-MR imaging. In order to serve as a reliable tool for the assessment of clinical stroke or brain tumor patients, we investigated the repeatability and reproducibility of cerebral sodium (23Na) imaging in healthy subjects. METHODS: In this prospective, IRB approved study 12 consecutive healthy volunteers (8 female, age 31 ± 8.3) underwent three cerebral 23Na-MRI examinations at 3.0 T (TimTrio, Siemens Healthineers) distributed between two separate visits with an 8 day interval. For each scan a T1w MP-RAGE sequence for anatomical referencing and a 3D-density-adapted, radial GRE-sequence for 23Na-imaging were acquired using a dual-tuned (23Na/1H) head-coil. On 1 day, these scans were repeated consecutively; on the other day, the scans were performed once. 23Na-sequences were reconstructed according to the MP-RAGE sequence, allowing direct cross-referencing of ROIs. Circular ROIs were placed in predetermined anatomic regions: gray and white matter (GM, WM), head of the caudate nucleus (HCN), pons, and cerebellum. External 23Na-reference phantoms were used to calculate the tissue sodium content. RESULTS: Excellent correlation was found between repeated measurements on the same day (r2 = 0.94), as well as on a different day (r2 = 0.86). No significant differences were found based on laterality other than in the HCN (63.1 vs. 58.7 mmol/kg WW on the right (p = 0.01)). Pronounced inter-individual differences were identified in all anatomic regions. Moderate to good correlation (0.310 to 0.701) was found between the readers. CONCLUSION: Our study has shown that intra-individual 23Na-concentrations in healthy subjects do not significantly differ after repeated scans on the same day and a pre-set time interval. This confirms the repeatability and reproducibility of cerebral 23Na-imaging. However, with manual ROI placement in predetermined anatomic landmarks, fluctuations in 23Na-concentrations can be observed.


Assuntos
Encéfalo/diagnóstico por imagem , Imagem por Ressonância Magnética/métodos , Sódio/administração & dosagem , Adulto , Núcleo Caudado/diagnóstico por imagem , Feminino , Substância Cinzenta/diagnóstico por imagem , Voluntários Saudáveis , Humanos , Imagem por Ressonância Magnética/instrumentação , Masculino , Variações Dependentes do Observador , Imagens de Fantasmas , Ponte/diagnóstico por imagem , Estudos Prospectivos , Reprodutibilidade dos Testes , Substância Branca/diagnóstico por imagem , Adulto Jovem
9.
Neuron ; 102(1): 17-20, 2019 04 03.
Artigo em Inglês | MEDLINE | ID: mdl-30946819

RESUMO

Recent research has identified a single factor accounting for broad risk to experience common forms of psychopathology. Structural alterations of cerebellar circuitry have emerged as a neural nexus of this broad risk, highlighting the cerebellum's importance for executive control.


Assuntos
Cerebelo/diagnóstico por imagem , Transtornos Mentais , Anisotropia , Cerebelo/patologia , Cerebelo/fisiopatologia , Suscetibilidade a Doenças , Neuroimagem Funcional , Substância Cinzenta/diagnóstico por imagem , Substância Cinzenta/patologia , Humanos , Imagem por Ressonância Magnética , Vias Neurais , Tamanho do Órgão , Ponte/diagnóstico por imagem , Ponte/patologia , Córtex Pré-Frontal/diagnóstico por imagem , Psicopatologia , Risco , Tálamo , Substância Branca/diagnóstico por imagem , Substância Branca/patologia
10.
Neuroradiology ; 61(6): 703-710, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31011773

RESUMO

PURPOSE: Altered brain volume and metabolic variables have been found in subjects with obesity. However, the role of metabolic parameters in gray matter volume (GMV) has been poorly investigated. This study aimed to investigate the relationship between the metabolic parameters and brain volume in subjects with obesity. METHODS: Thirty-seven subjects with obesity and 39 age and sex matched normal-weight controls were included in this study. Eighteen of the 37 participants who underwent sleeve gastrectomy were included in the longitudinal analysis. Blood samples and high-resolution 3T T1-weighted magnetic resonance images were collected. Metabolic parameters in plasma and GMV were measured. RESULTS: Multiple linear regression analysis showed that gray matter reduction in several cognition-related cortices including right angular gyrus, superior occipital cortex, superior parietal cortex, and cerebellum was related to decreased creatinine, as well as increased triglyceride, HbA1c, and low-density lipoprotein in plasma in subjects with obesity. Weight loss after the surgery induced significant recovery of altered metabolic parameters and decreased gray matter volume. Furthermore, changes in the four metabolic parameters before and after the surgery were associated with changes in gray matter volume. CONCLUSION: Our results suggest that the gray matter reduction is related to decreased creatinine as well as increased triglyceride, HbA1c, and low-density lipoprotein in plasma in subjects with obesity.


Assuntos
Creatinina/sangue , Hemoglobina A Glicada/metabolismo , Substância Cinzenta/patologia , Lipoproteínas LDL/sangue , Imagem por Ressonância Magnética/métodos , Obesidade/sangue , Obesidade/complicações , Triglicerídeos/sangue , Adolescente , Adulto , Biomarcadores/sangue , Estudos de Casos e Controles , Feminino , Substância Cinzenta/diagnóstico por imagem , Humanos , Estudos Longitudinais , Masculino , Tamanho do Órgão
11.
Mil Med ; 184(Suppl 1): 218-227, 2019 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-30901451

RESUMO

RESEARCH OBJECTIVES: It is widely accepted that mild traumatic brain injury (mTBI) causes injury to the white matter, but the extent of gray matter (GM) damage in mTBI is less clear. METHODS: We tested 26 civilian healthy controls and 14 civilian adult subacute-chronic mTBI patients using quantitative features of MRI-based Gradient Echo Plural Contrast Imaging (GEPCI) technique. GEPCI data were reconstructed using previously developed algorithms allowing the separation of R2t*, a cellular-specific part of gradient echo MRI relaxation rate constant, from global R2* affected by BOLD effect and background gradients. RESULTS: Single-subject voxel-wise analysis (comparing each mTBI patient to the sample of 26 control subjects) revealed GM abnormalities that were not visible on standard MRI images (T1w and T2w). Analysis of spatial overlap for voxels with low R2t* revealed tissue abnormalities in multiple GM regions, especially in the frontal and temporal regions, that are frequently damaged after mTBI. The left posterior insula was the region with abnormalities found in the highest proportion (50%) of mTBI patients. CONCLUSIONS: Our data suggest that GEPCI quantitative R2t* metric has potential to detect abnormalities in GM cellular integrity in individual TBI patients, including abnormalities that are not detectable by a standard clinical MRI.


Assuntos
Meios de Contraste/uso terapêutico , Substância Cinzenta/lesões , Imagem por Ressonância Magnética/métodos , Adulto , Idoso , Encéfalo/anormalidades , Encéfalo/diagnóstico por imagem , Encéfalo/fisiopatologia , Feminino , Substância Cinzenta/diagnóstico por imagem , Humanos , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos , Projetos Piloto
12.
J Affect Disord ; 251: 78-85, 2019 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-30909161

RESUMO

BACKGROUND: Major depressive disorder (MDD) has been assumed to be associated with aberrant brain connectivity. However, research suggests that brain connectivity abnormalities should not be restricted to extrinsic white matter connectivity, but may also impact on intrinsic gray matter connectivity. Therefore, our study aimed to investigate the intrinsic gray-matter connectivity in MDD. METHODS: The participants were 16 first-episode, drug-naïve patients with MDD and 16 healthy controls matched on age and gender. All participants were scanned by 3.0T structural magnetic resonance imaging. Global and local intrinsic gray-matter connectivity were measured based on surface-based geodesic distances, including mean coritical separation distances (MSDs), perimeter function, and radius function. RESULTS: MDD patients had significantly lower MSDs in the left postcentral gyrus and higher MSDs in the left superior parietal cortex. Marginally significant correlation was observed between MSDs in the left postcentral gyrus and symptoms of depression. Compared with healthy controls, depressed subjects had abnormal local intrinsic gray-matter connectivity in the left postcentral gyrus, the left transverse temporal gyrus, the right lingual gyrus, the right lateral occipital cortex, and the right superior frontal gyrus. Furthermore, local intrinsic gray matter connections of these brain areas were associated with some symptoms of depression. LIMITATIONS: The small sample size limited the interpretability of our potential conclusions. CONCLUSION: Aberrant intrinsic gray-matter connectivity was observed in depressed subjects, indicating abnormal intrinsic wiring cost of brain architecture. This might help explain the aberrant topological properties of brain functional connectivity and provide insights into the vulnerability of MDD.


Assuntos
Transtorno Depressivo Maior/fisiopatologia , Substância Cinzenta/fisiopatologia , Rede Nervosa/fisiopatologia , Adulto , Encéfalo/fisiopatologia , Encefalopatias/fisiopatologia , Mapeamento Encefálico , Transtorno Depressivo Maior/diagnóstico por imagem , Feminino , Substância Cinzenta/diagnóstico por imagem , Humanos , Imagem por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Rede Nervosa/diagnóstico por imagem , Lobo Occipital/fisiopatologia , Lobo Parietal/fisiopatologia , Córtex Pré-Frontal/fisiopatologia , Substância Branca/patologia
13.
J Med Syst ; 43(5): 117, 2019 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-30905048

RESUMO

In order to explore the brain functional and structural imaging results of patients with bipolar disorder and depressive episode without taking medicine, and to further explore the disease mechanism of bipolar disorder by combining with clinical symptoms and cognitive function (neuropsychological test), DPABI (Data Processing and Analysis (Resting-State) For Brain Image) software is used to pre-process fMRI (functional magnetic resonance imaging) data and calculate fALFF (ratio low frequency fluctuation amplitude) index. In addition, SPM8 is applied for grey matter volume analysis based on voxel morphology. Pearson correlation model is used to analyze the relationship between functional and morphological changes and clinical symptoms and cognitive tests. DPABI software and SPSS 22.0 software are used to analyze the data. The results show that corresponding abnormal brain areas are found in both functional and structural aspects of patients with bipolar disorder and depression, involving LCSPT emotional circuits. More importantly, the superior frontal gyrus shows significant abnormalities in both functional and structural analysis.


Assuntos
Transtorno Bipolar/patologia , Transtornos Cognitivos/patologia , Transtorno Depressivo/patologia , Substância Cinzenta/patologia , Processamento de Imagem Assistida por Computador/métodos , Adolescente , Adulto , Grupo com Ancestrais do Continente Asiático , Transtorno Bipolar/diagnóstico por imagem , Transtorno Bipolar/epidemiologia , Encéfalo/patologia , Transtornos Cognitivos/diagnóstico por imagem , Transtornos Cognitivos/epidemiologia , Transtorno Depressivo/diagnóstico por imagem , Transtorno Depressivo/epidemiologia , Escolaridade , Feminino , Substância Cinzenta/diagnóstico por imagem , Humanos , Imagem por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos , Tamanho do Órgão/fisiologia , Adulto Jovem
14.
Neuroradiology ; 61(5): 585-593, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30877333

RESUMO

PURPOSE: A combination of the caloric test with functional magnetic resonance imaging (fMRI) is a promising method for a comprehensive diagnostics of pathologies of the vestibular system. The aim of this study was to investigate the potential pattern of grey matter local activation in fMRI using cold and hot caloric stimulation in patients presenting unilateral peripheral vestibular injury. METHODS: Forty right-handed participants aged 27 to 56 with the diagnosis of right-sided peripheral vestibular hypofunction were included. Stimulation was performed separately for the right and the left ear with cold (C, 14-15 °C) stimulus and hot (H, 48-49 °C) stimulus. Grey matter activation was assessed in BOLD technique using a 3T scanner. RESULTS: We observed activity within the parieto-insular vestibular cortex (PIVC), thalamus, insula and retroinsular area, hippocampus, and cerebellum, as well as oculomotor centers located in the precentral gyrus, superior temporal gyrus, and intraparietal sulcus. Cold stimulus resulted in more areas of activation in response to the right ear activation rather than to the left ear. The ipsilateral activity was noted for insular cortex and intraparietal sulcus. The differences between hot and cold stimuli were noted for the right ear. CONCLUSIONS: In this preliminary study, the combination of the caloric test and fMRI allowed to present specific pattern of grey matter activation in patients with unilateral peripheral vestibular injury. Further studies are necessary to develop patterns or cortical maps differentiating various balance disorders and to analyze the dynamics of cortical plasticity after the injury.


Assuntos
Testes Calóricos , Substância Cinzenta/diagnóstico por imagem , Substância Cinzenta/fisiopatologia , Imagem por Ressonância Magnética , Doenças Vestibulares/fisiopatologia , Adulto , Feminino , Lateralidade Funcional/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade
15.
Nat Commun ; 10(1): 1140, 2019 03 08.
Artigo em Inglês | MEDLINE | ID: mdl-30850610

RESUMO

Accurate estimates of the BOLD hemodynamic response function (HRF) are crucial for the interpretation and analysis of event-related functional MRI data. To date, however, there have been no comprehensive measurements of the HRF in white matter (WM) despite increasing evidence that BOLD signals in WM change after a stimulus. We performed an event-related cognitive task (Stroop color-word interference) to measure the HRF in selected human WM pathways. The task was chosen in order to produce robust, distributed centers of activity throughout the cortex. To measure the HRF in WM, fiber tracts were reconstructed between each pair of activated cortical areas. We observed clear task-specific HRFs with reduced magnitudes, delayed onsets and prolonged initial dips in WM tracts compared with activated grey matter, thus calling for significant changes to current standard models for accurately characterizing the HRFs in WM and for modifications of standard methods of analysis of functional imaging data.


Assuntos
Córtex Cerebral/fisiologia , Substância Cinzenta/fisiologia , Rede Nervosa/fisiologia , Reconhecimento Visual de Modelos/fisiologia , Substância Branca/fisiologia , Adulto , Córtex Cerebral/diagnóstico por imagem , Circulação Cerebrovascular/fisiologia , Feminino , Substância Cinzenta/diagnóstico por imagem , Voluntários Saudáveis , Hemodinâmica/fisiologia , Hemoglobinas/análise , Hemoglobinas/fisiologia , Humanos , Imagem por Ressonância Magnética , Masculino , Rede Nervosa/diagnóstico por imagem , Oxigênio/análise , Oxigênio/fisiologia , Teste de Stroop , Substância Branca/diagnóstico por imagem
16.
J Clin Neurosci ; 63: 55-61, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30827879

RESUMO

Occipital bending (OB) describes asymmetry of the occipital lobes where one lobe wraps across the midline, and has been associated with the presence of mood disorders. We evaluated the relationship between OB and major depressive disorder (MDD) in a large population of subjects from the International Study to Predict Optimized Treatment in Depression. MDD patients (n = 231) and healthy controls (n = 68) underwent MRI and neuropsychiatric evaluation, including response or remission to antidepressant medication at baseline and at 8 weeks. Cortical thickness, ventricular volumes and regional grey matter volumes were measured. OB was visually assessed and OB angle measured using a semi-automated method. Correlations with MDD diagnosis, MRI measures and clinical features were tested. Results demonstrated a greater proportion of rightwards OB in MDD compared to control subjects (p = 0.02). There was no difference in the total prevalence of OB (combined left and rightward bending) between MDD and controls. MDD subjects with right OB had greater cortical thickness in three medial occipital regions (cuneus, lingual gyrus and calcarine sulcus) on the left. Lateral ventricular size was 20% lower bilaterally in right OB MDD subjects compared to non-OB MDD subjects. OB was not associated with severity (HDRS-17). Our data suggest the presence of a strong link between greater rightward occipital bending and MDD. Rightward-OB is associated with greater left medial occipital cortical thickness, and with reduced lateral ventricular size. The cause for greater rightward bending in MDD patients is unclear, however our data suggest a developmental aetiology.


Assuntos
Antidepressivos/uso terapêutico , Transtorno Depressivo Maior/diagnóstico por imagem , Lobo Occipital/diagnóstico por imagem , Adulto , Transtorno Depressivo Maior/tratamento farmacológico , Feminino , Substância Cinzenta/diagnóstico por imagem , Humanos , Imagem por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Prognóstico
17.
Magn Reson Imaging ; 58: 156-161, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30771445

RESUMO

The tumor microenvironment is characteristically acidic and this extracellular acidosis is known to play a role in carcinogenesis and metastasis and can affect tumor chemosensitivity and radiosensitivity. Intracellular pH has been used as a possible biomarker of salvageable tissue in ischemic stroke. A non-invasive MRI-based approach for the determination and imaging of cerebral pH would be a powerful tool in cancer diagnosis and monitoring, as well as stroke treatment planning. Several pH-based MRI imaging approaches have been proposed but for these to be useful, disentangling the effects of pH from other parameters which may affect the measured MRI signal is crucial to ensure accuracy and specificity. R1 relaxation in the rotating frame (R1ρ) is an example of a method that has been proposed to probe pH in vivo using MRI. In this study, we have investigated the relationship between R1ρ, pH, and macromolecular density in vitro using phantoms and in human volunteers. Here we show that the rate of R1ρ relaxation (=1/T1ρ) varies with pH but only in the presence of macromolecules. At constant pH, phantom macromolecular density inversely correlated with R1ρ. R1ρ imaging of the normal human brain demonstrated regional heterogeneity with significant differences between structurally distinct regions, which are likely to be independent of pH. For example, R1ρ was higher in the basal ganglia compared to grey matter and higher in grey matter compared to white matter. We conclude that R1ρ cannot be reliably used to image tissue pH without deconvolution from the effects of local tissue macromolecular composition.


Assuntos
Concentração de Íons de Hidrogênio , Substâncias Macromoleculares/química , Imagem por Ressonância Magnética , Imagens de Fantasmas , Gânglios da Base/diagnóstico por imagem , Encéfalo/diagnóstico por imagem , Isquemia Encefálica/diagnóstico por imagem , Mapeamento Encefálico , Meios de Contraste/química , Gadolínio/química , Substância Cinzenta/diagnóstico por imagem , Voluntários Saudáveis , Humanos , Masculino , Metástase Neoplásica , Neoplasias/diagnóstico por imagem , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Acidente Vascular Cerebral/diagnóstico por imagem , Microambiente Tumoral , Adulto Jovem
18.
Proc Natl Acad Sci U S A ; 116(8): 3316-3321, 2019 02 19.
Artigo em Inglês | MEDLINE | ID: mdl-30718430

RESUMO

Mind wandering represents the human capacity for internally focused thought and relies upon the brain's default network and its interactions with attentional networks. Studies have characterized mind wandering in healthy people, yet there is limited understanding of how this capacity is affected in clinical populations. This paper used a validated thought-sampling task to probe mind wandering capacity in two neurodegenerative disorders: behavioral variant frontotemporal dementia [(bvFTD); n = 35] and Alzheimer's disease [(AD); n = 24], compared with older controls (n = 37). These patient groups were selected due to canonical structural and functional changes across sites of the default and frontoparietal networks and well-defined impairments in cognitive processes that support mind wandering. Relative to the controls, bvFTD patients displayed significantly reduced mind wandering capacity, offset by a significant increase in stimulus-bound thought. In contrast, AD patients demonstrated comparable levels of mind wandering to controls, in the context of a relatively subtle shift toward stimulus-/task-related forms of thought. In the patient groups, mind wandering was associated with gray matter integrity in the hippocampus/parahippocampus, striatum, insula, and orbitofrontal cortex. Resting-state functional connectivity revealed associations between mind wandering capacity and connectivity within and between regions of the frontoparietal and default networks with distinct patterns evident in patients vs. controls. These findings support a relationship between altered mind wandering capacity in neurodegenerative disorders and structural and functional integrity of the default and frontoparietal networks. This paper highlights a dimension of cognitive dysfunction not well documented in neurodegenerative disorders and validates current models of mind wandering in a clinical population.


Assuntos
Doença de Alzheimer/fisiopatologia , Atrofia/fisiopatologia , Encefalopatias/fisiopatologia , Hipocampo/fisiopatologia , Idoso , Idoso de 80 Anos ou mais , Doença de Alzheimer/diagnóstico por imagem , Atrofia/diagnóstico por imagem , Atenção/fisiologia , Encefalopatias/diagnóstico por imagem , Mapeamento Encefálico , Feminino , Demência Frontotemporal/diagnóstico por imagem , Demência Frontotemporal/fisiopatologia , Substância Cinzenta/diagnóstico por imagem , Substância Cinzenta/fisiopatologia , Hipocampo/diagnóstico por imagem , Humanos , Processamento de Imagem Assistida por Computador , Imagem por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Degeneração Neural/diagnóstico por imagem , Degeneração Neural/fisiopatologia , Rede Nervosa/fisiologia , Vias Neurais/fisiologia , Descanso/fisiologia , Lobo Temporal/diagnóstico por imagem , Lobo Temporal/fisiopatologia
19.
J Appl Genet ; 60(2): 151-162, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30706430

RESUMO

Autosomal recessive primary microcephaly (MCPH) is a group of rare neurodevelopmental diseases with severe microcephaly at birth. One type of the disorder, MCPH2, is caused by biallelic mutations in the WDR62 gene, which encodes the WD repeat-containing protein 62. Patients with WDR62 mutation may have a wide range of malformations of cortical development in addition to congenital microcephaly. We describe two patients, a boy and a girl, with severe congenital microcephaly, global developmental delay, epilepsy, and failure to thrive. MRI showed hemispherical asymmetry, diffuse pachygyria, thick gray matter, indistinct gray-white matter junction, and corpus callosum and white matter hypoplasia. Whole exome sequencing revealed the same novel homozygous missense mutation, c.668T>C, p.Phe223Ser in exon 6 of the WDR62 gene. The healthy parents were heterozygous for this mutation. The mutation affects a highly conserved region in one of the WD repeats of the WDR62 protein. Haplotype analysis showed genetic relatedness between the families of the patients. Our findings expand the spectrum of mutations randomly distributed in the WDR62 gene. A review is also provided of the brain malformations described in WDR62 mutations in association with congenital microcephaly.


Assuntos
Deficiências do Desenvolvimento/genética , Microcefalia/genética , Proteínas do Tecido Nervoso/genética , Deficiências do Desenvolvimento/diagnóstico por imagem , Deficiências do Desenvolvimento/fisiopatologia , Feminino , Substância Cinzenta/diagnóstico por imagem , Substância Cinzenta/patologia , Haplótipos , Homozigoto , Humanos , Masculino , Microcefalia/diagnóstico por imagem , Microcefalia/fisiopatologia , Mutação de Sentido Incorreto/genética , Linhagem , Substância Branca/diagnóstico por imagem , Substância Branca/patologia
20.
J Affect Disord ; 245: 971-977, 2019 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-30699883

RESUMO

BACKGROUND: Major depressive disorder (MDD) is accompanied by atypical brain structure affecting grey and white matter from the early stages. Neuroimaging studies of first-episode depression (FED) have provided evidence on this regard, but most of the studies are cross-sectional. The aim of this longitudinal study was to test potential changes in grey matter (GM) and white matter (WM) volumes in FED. METHODS: Thirty-three untreated FED patients (DSM-IV criteria) and 33 healthy controls (HC) underwent a 3T structural magnetic resonance imaging (sMRI) at baseline and after 2 years. Depressive symptoms were assessed at baseline and throughout the study with the 17-item Hamilton Depressive Rating Scale (HDRS-17). Recurrences of FED patients were also collected along the follow-up. To analyze GM and WM differences, whole-brain voxel-based morphometry (VBM, SPM12) was employed (FWE corrected). RESULTS: FED patients showed significant reductions compared to HC in WM volumes of prefrontal cortex (left anterior corona radiata). No differences were found in GM volumes. Full factorial longitudinal analysis of the whole sample revealed no significant effect in GM nor in WM, while the full factorial longitudinal analysis comparing recurrent and non-recurrent patients showed increments in WM volumes of left posterior corona radiata and right posterior thalamic radiation in the recurrent group. LIMITATIONS: Limited sample size, especially in the follow-up. CONCLUSIONS: The present findings provided some new evidence of the role of white matter alterations in the early stages of MDD and in the progression of the illness.


Assuntos
Depressão/diagnóstico por imagem , Transtorno Depressivo Maior/diagnóstico por imagem , Substância Cinzenta/diagnóstico por imagem , Córtex Pré-Frontal/diagnóstico por imagem , Substância Branca/diagnóstico por imagem , Adulto , Encéfalo/diagnóstico por imagem , Encéfalo/patologia , Estudos de Casos e Controles , Estudos Transversais , Depressão/patologia , Transtorno Depressivo Maior/patologia , Progressão da Doença , Feminino , Substância Cinzenta/patologia , Humanos , Estudos Longitudinais , Imagem por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Tamanho do Órgão , Córtex Pré-Frontal/patologia , Substância Branca/patologia
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