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Sökning: WFRF:(Spulber G)

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1.
  • Macfarlane, M. D., et al. (författare)
  • Shape abnormalities of the caudate nucleus correlate with poorer gait and balance: Results from a subset of the ladis study
  • 2015
  • Ingår i: The American journal of geriatric psychiatry. - 1064-7481. ; 23:1, s. 59-U90
  • Tidskriftsartikel (refereegranskat)abstract
    • Objective Functional deficits seen in several neurodegenerative disorders have been linked with dysfunction in frontostriatal circuits and with associated shape alterations in striatal structures. The severity of visible white matter hyperintensities (WMHs) on magnetic resonance imaging has been found to correlate with poorer performance on measures of gait and balance. This study aimed to determine whether striatal volume and shape changes were correlated with gait dysfunction. Methods Magnetic resonance imaging scans and clinical gait/balance data (scores from the Short Physical Performance Battery [SPPB]) were sourced from 66 subjects in the previously published LADIS trial, performed in nondisabled individuals older than age 65 years with WMHs at study entry. Data were obtained at study entry and at 3-year follow-up. Caudate nuclei and putamina were manually traced using a previously published method and volumes calculated. The relationships between volume and physical performance on the SPPB were investigated with shape analysis using the spherical harmonic shape description toolkit. Results There was no correlation between the severity of WMHs and striatal volumes. Caudate nuclei volume correlated with performance on the SPPB at baseline but not at follow-up, with subsequent shape analysis showing left caudate changes occurred in areas corresponding to inputs of the dorsolateral prefrontal, premotor, and motor cortex. There was no correlation between putamen volumes and performance on the SPPB. Conclusion Disruption in frontostriatal circuits may play a role in mediating poorer physical performance in individuals with WMHs. Striatal volume and shape changes may be suitable biomarkers for functional changes in this population. © 2015 American Association for Geriatric Psychiatry.
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2.
  • Besga, A., et al. (författare)
  • Differences in brain cholesterol metabolism and insulin in two subgroups of patients with different CSF biomarkers but similar white matter lesions suggest different pathogenic mechanisms
  • 2012
  • Ingår i: Neuroscience Letters. - 0304-3940 .- 1872-7972. ; 510:2, s. 121-126
  • Tidskriftsartikel (refereegranskat)abstract
    • Investigate possible associations of white matter hyperintensities (WMHs) with the metabolism of cholesterol and insulin in two subgroups of patients with memory complaints and different CSF A beta 42 and CSF tau levels. 59 patients from the memory clinic at Karolinska Hospital were included. Degree of WMHs was rated using the ARWMC scale and the following biomarkers were measured in CSF and plasma: insulin, cholesterol, lanosterol, lathosterol, and oxidized cholesterol metabolites. The WMHs in CSF control-like group correlated with increased brain cholesterol synthesis and reduced efflux of oxysterols and insulin in CSF. In the CSF AD-like group, the WMHs correlated with increased peripheral cholesterol metabolism. Despite having similar appearance on FLAIR images, the pathogenic mechanisms of WMHS are likely to be different in the two groups investigated.
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3.
  • Damangir, Soheil, et al. (författare)
  • Multispectral MRI segmentation of age related white matter changes using a cascade of support vector machines
  • 2012
  • Ingår i: Journal of the Neurological Sciences. - 0022-510X .- 1878-5883. ; 322:1-2, s. 211-216
  • Tidskriftsartikel (refereegranskat)abstract
    • White matter changes (WMC) are the focus of intensive research and have been linked to cognitive impairment and depression in the elderly. Cumbersome manual outlining procedures make research on WMC labor intensive and prone to subjective bias. We present a fast, fully automated method for WMC segmentation using a cascade of reduced support vector machines (SVMs) with active learning. Data of 102 subjects was used in this study. Two MRI sequences (T1-weighted and FLAIR) and masks of manually outlined WMC from each subject were used for the image analysis. The segmentation framework comprises pre-processing, classification (training and core segmentation) and post-processing. After pre-processing, the model was trained on two subjects and tested on the remaining 100 subjects. The effectiveness and robustness of the classification was assessed using the receiver operating curve technique. The cascade of SVMs segmentation framework outputted accurate results with high sensitivity (90%) and specificity (99.5%) values, with the manually outlined WMC as reference. An algorithm for the segmentation of WMC is proposed. This is a completely competitive and fast automatic segmentation framework, capable of using different input sequences, without changes or restrictions of the image analysis algorithm.
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4.
  • Follin, Cecilia, et al. (författare)
  • Impaired brain metabolism and neurocognitive function in childhood leukemia survivors despite complete hormone supplementation in adulthood
  • 2016
  • Ingår i: Psychoneuroendocrinology. - : Elsevier. - 0306-4530 .- 1873-3360. ; 73, s. 157-165
  • Tidskriftsartikel (refereegranskat)abstract
    • Cranial radiotherapy is a known risk factor for neurocognitive impairment in survivors of childhood acute lymphoblastic leukemia (ALL). Understanding the nature of cognitive dysfunction during adulthood in ALL survivors is important as it has an impact on major life situations. Thirty-eight (21 women) ALL survivors were investigated 34 years after diagnosis. Median-age was 38 (27–46) years. All were treated with a CRT dose of 24 Gy and 11 years (3–13) of complete hormone supplementation. Comparisons were made to 29 matched controls. Assessments of magnetic resonance spectroscopy (white and grey matter metabolic alterations), brain volume and neuropsychological tests were performed. ALL survivors demonstrate a generally lower performance in neuropsychological tests. ALL survivors scored lower than controls in vocabulary (p < 0.001), memory (p < 0.001), learning capacity (p < 0.001), spatial ability (p < 0.001), executive functions and attention (p < 0.001) 34 years after ALL treatment. Compared to controls ALL survivors had reduced white matter (WM) (492 vs 536 cm3, p < 0.001) and grey matter (GM) volumes (525 vs 555 cm3, p = 0.001). ALL survivors had lower levels of WM N-acetyl aspartate/creatin (NAA/Cr) (1.48 vs 1.63, p = 0.004), WM NAA + NAAG (N-acetylaspartylglutamate)/Cr (1.61 vs 1.85, p < 0.001) and lower levels of GM NAA/Cr (1.18 vs 1.30, p = 0.001) and GM NAA + NAAG/Cr (1.28 vs 1.34, p = 0.01) compared to controls. ALL survivors had higher levels in WM MI (Myoinositol)/NAA (0.65 vs 0.56, p = 0.01) concentrations compared to controls. There was a significantly negative correlation of years since ALL diagnosis to WM NAA + NAAG/Cr (r = −0.4, p = 0.04) in ALL survivors. The present study shows impaired brain metabolism detected by MRS, reduced brain volumes and neurocognitive impairment in childhood ALL survivors treated with cranial radiotherapy and chemotherapy, despite complete hormone substitution. We also report an impairment of metabolites correlated to time since treatment and a progressive impairment in sustained attention, suggesting an accelerated aging in the irradiated brain. Following these survivors many decades, or throughout life, after treatment with cranial radiotherapy and chemotherapy is highly warranted for a broader understanding of long-term outcome in this patient group.
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5.
  • Hooshmand, Babak, et al. (författare)
  • Vitamin D in Relation to Cognitive Impairment, Cerebrospinal Fluid Biomarkers, and Brain Volumes
  • 2014
  • Ingår i: The journals of gerontology. Series A, Biological sciences and medical sciences. - 1079-5006 .- 1758-535X. ; 69:9, s. 1132-1138
  • Tidskriftsartikel (refereegranskat)abstract
    • Background. Low vitamin D status is associated with poorer cognitive function in older adults, but little is known about the potential impact on cerebrospinal fluid (CSF) biomarkers and brain volumes. The objective of this study was to examine the relations between plasma 25-hydroxyvitamin D (25(OH)D) and cognitive impairment, CSF biomarkers of Alzheimer's disease (AD), and structural brain tissue volumes. Methods. A total of 75 patients (29 with subjective cognitive impairment, 28 with mild cognitive impairment, 18 with AD) referred to the Memory Clinic at Karolinska University Hospital, Huddinge, Sweden were recruited. Plasma 25(OH)D, CSF levels of amyloid beta (A beta(1-42)), total-tau, and phosphorylated tau, and brain tissue volumes have been measured. Results. After adjustment for several potential confounders, the odds ratios (95% confidence interval) for cognitive impairment were as follows: 0.969 (0.948-0.990) per increase of 1 nmol/L of 25(OH) D and 4.19 (1.30-13.52) for 24(OH) D values less than 50 nmol/L compared with values greater than or equal to 50 nmol/L. Adjusting for CSF A beta(1-42) attenuated the 25(OH) D-cognition link. In a multiple linear regression analysis, higher 25(OH)D levels were related to higher concentrations of CSF A beta(1-42) and greater brain volumes (eg, white matter, structures belonging to medial temporal lobe). The associations between 25(OH)D and tau variables were not significant. Conclusions. This study suggests that vitamin D may be associated with cognitive status, CSF A beta(1-42) levels, and brain tissue volumes.
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6.
  • Lebedev, Alexander V., et al. (författare)
  • Effects of daily L-dopa administration on learning and brain structure in older adults undergoing cognitive training : a randomised clinical trial
  • 2020
  • Ingår i: Scientific Reports. - 2045-2322. ; 10
  • Tidskriftsartikel (refereegranskat)abstract
    • Cognitive aging creates major individual and societal burden, motivating search for treatment and preventive care strategies. Behavioural interventions can improve cognitive performance in older age, but effects are small. Basic research has implicated dopaminergic signalling in plasticity. We investigated whether supplementation with the dopamine-precursor L-dopa improves effects of cognitive training on performance. Sixty-three participants for this randomised, parallel-group, double-blind, placebo-controlled trial were recruited via newspaper advertisements. Inclusion criteria were: age of 65–75 years, Mini-Mental State Examination score >25, absence of serious medical conditions. Eligible subjects were randomly allocated to either receive 100/25 mg L-dopa/benserazide (n = 32) or placebo (n = 31) prior to each of twenty cognitive training sessions administered during a four-week period. Participants and staff were blinded to group assignment. Primary outcomes were latent variables of spatial and verbal fluid intelligence. Compared to the placebo group, subjects receiving L-dopa improved less in spatial intelligence (−0.267 SDs; 95%CI [−0.498, −0.036]; p = 0.024). Change in verbal intelligence did not significantly differ between the groups (−0.081 SDs, 95%CI [−0.242, 0.080]; p = 0.323). Subjects receiving L-dopa also progressed slower through the training and the groups displayed differential volumetric changes in the midbrain. No statistically significant differences were found for the secondary cognitive outcomes. Adverse events occurred for 10 (31%) and 7 (23%) participants in the active and control groups, correspondingly. The results speak against early pharmacological interventions in older healthy adults to improve broader cognitive functions by targeting the dopaminergic system and provide no support for learning-enhancing properties of L-dopa supplements in the healthy elderly. The findings warrant closer investigation about the cognitive effects of early dopamine-replacement therapy in neurological disorders. This trial was preregistered at the European Clinical Trial Registry, EudraCT#2016-000891-54 (2016-10-05).
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7.
  • Liu, Yawu, et al. (författare)
  • Diffusion tensor imaging and tract-based spatial statistics in Alzheimer's disease and mild cognitive impairment
  • 2011
  • Ingår i: Neurobiology of Aging. - Fayetteville, N.Y. : Ankho International. - 0197-4580 .- 1558-1497. ; 32:9, s. 1558-1571
  • Tidskriftsartikel (refereegranskat)abstract
    • We aimed to explore the changes in fractional anisotropy (FA) in subjects with mild cognitive impairment (MCI) and Alzheimer's disease (AD) by analyzing diffusion tensor imaging (DTI) data using the Tract-Based Spatial Statistics (TBSS). DTI data were collected from 17 AD patients, 27 MCI subjects and 19 healthy controls. Voxel-based analysis with TBSS was used to compare FA among the three groups. Additionally, guided by TBSS findings, a region of interest (ROI)-based analysis along the TBSS skeleton was performed on group-level and the accuracy of the method was assessed by the back-projection of ROIs to the native space FA. Neurofiber tracts with decreased FA included: the parahippocampal white matter, cingulum, uncinate fasciculus, inferior and superior longitudinal fasciculus, corpus callosum, fornix, tracts in brain stem, and cerebellar tracts. Quantitative ROI-analysis further demonstrated the significant decrease on FA values in AD patients relative to controls whereas FA values of MCI patients were found in between the controls and AD patients. We conclude that TBSS is a promising method in examining the degeneration of neurofiber tracts in MCI and AD patients.
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9.
  • Miralbell, Julia, et al. (författare)
  • Grey matter and cognitive patterns in cognitive impaired subjects using CSF biomarker cut-offs
  • 2012
  • Ingår i: Journal of Alzheimer's Disease. - 1387-2877 .- 1875-8908. ; 29:4, s. 741-749
  • Tidskriftsartikel (refereegranskat)abstract
    • The aim of this study was to investigate brain tissue volumes, grey matter (GM) distribution, and cognitive performance for cognitively impaired subjects using cerebrospinal fluid (CSF) biomarker cut-offs as grouping criteria. 41 subjects attending the Memory Clinic, Karolinska University Hospital, Huddinge, Sweden, were divided into groups based on normal or abnormal CSF levels of Aβ1-42, t-tau, and p-tau181. SIENAX algorithms were employed for brain tissue volumes estimation and voxel-based morphometry (VBM) for mapping the differences in GM patterns. VBM revealed significant lower GM volumes in temporo-parietal, occipital, and prefrontal cortices for those subjects belonging to abnormal CSF t-tau and p-tau181 groups. No differences were found between groups according to CSF Aβ1-42 cut-offs. Patients with abnormal CSF p-tau181 showed lower cognitive performance compared to those with normal levels. Patients with abnormal levels of CSF tau (but not Aβ1-42) showed an Alzheimer's disease-like pattern for both GM distribution and cognitive profile, compared to those with normal levels. These results support the hypothesis that CSF t-tau or p-tau181 levels may be of direct value for the evaluation of disease severity.
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10.
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