Amyotrophic lateral sclerosis (ALS) is now universally recognized as a complex multisystem disorder with considerable extra-motor involvement. The neuropsychological manifestations of frontotemporal, ...parietal, and basal ganglia involvement in ALS have important implications for compliance with assistive devices, survival, participation in clinical trials, caregiver burden, and the management of individual care needs. Recent advances in neuroimaging have been instrumental in characterizing the biological substrate of heterogeneous cognitive and behavioral deficits in ALS. In this review we discuss the clinical and radiological aspects of cognitive and behavioral impairment in ALS focusing on the recognition, assessment, and monitoring of these symptoms.
We investigated the potential of machine learning for diagnostic classification in late-life major depression based on an advanced whole brain white matter segmentation framework. Twenty-six ...late-life depression and 12 never depressed individuals aged > 55 years, matched for age, MMSE, and education underwent brain diffusion tensor imaging and a multi-contrast, multi-atlas segmentation in MRIcloud. Fractional anisotropy volume, mean fractional anisotropy, trace, axial and radial diffusivity (RD) extracted from 146 white matter parcels for each subject were used to train and test the AdaBoost classifier using stratified 12-fold cross validation. Performance was evaluated using various measures. The statistical power of the classifier was assessed using label permutation test. Statistical analysis did not yield significant differences in DTI measures between the groups. The classifier achieved a balanced accuracy of 71% and an Area Under the Receiver Operator Characteristic Curve (ROC-AUC) of 0.81 by trace, and a balanced accuracy of 70% and a ROC-AUC of 0.80 by RD, in limbic, cortico-basal ganglia-thalamo-cortical loop, brainstem, external and internal capsules, callosal and cerebellar structures. Both indices shared important structures for classification, while fornix was the most important structure for classification by both indices. The classifier proved statistically significant, as trace and RD ROC-AUC scores after permutation were lower than those obtained with the actual data (P = 0.022 and P = 0.024, respectively). Similar results were obtained with the Gradient Boosting classifier, whereas the RBF-kernel Support Vector Machine with k-best feature selection did not exceed the chance level. Finally, AdaBoost significantly predicted the class using all features together. Limitations are discussed. The results encourage further investigation of the implemented methods for computer aided diagnostics and anatomically informed therapeutics.
Cognitive impairment is a rapidly growing public health problem. As there is no curative treatment for dementia, the proactive management of modifiable risk factors and the identification of early ...biomarkers indicative of the cognitive decline are of great importance. Although nutrition is one of the most extensively studied lifestyle factor in relation to cognitive health, its association with brain magnetic resonance imaging (MRI) biomarkers is not well established. In the present work, we review available studies relating dietary or nutrient patterns with brain MRI biomarkers in dementia-free adults. Greater adherence to the Mediterranean diet has been associated with the preservation of structural connectivity and less brain atrophy in adults without dementia. In addition, specific nutrient patterns, characterized by a high intake of antioxidant vitamins, polyphenols and unsaturated fatty acids, have been related to larger brain volume. Although the results are encouraging regarding the role of dietary and nutrient patterns on imaging biomarkers, more well-designed observational longitudinal studies and clinical trials are needed in order to confirm potentially causal relationships and better understand underlying mechanisms.
Purpose
The aim of the study was to evaluate extraocular muscle (EOM) atrophy and fatty replacement in ocular myasthenia gravis (OMG) and generalized myasthenia gravis (GMG) patients with chronic and ...untreated ocular symptoms or with inadequate response to immunotherapy and unprovoked ocular exacerbations despite chronic immunotherapy.
Methods
Nineteen patients with either OMG or GMG and 19 healthy age-matched controls underwent an orbital MRI. Visually obvious muscle atrophy and muscle fatty replacement were evaluated by two raters independently. Maximum thickness of EOM was measured. Measurements of the muscles of each participant were added up, in order to calculate the total thickness.
Results
Eleven patients suffered from AChR-positive GMG, and 8 patients from OMG. All patients had chronic ocular symptoms or inadequate response to corticosteroids and unprovoked ocular exacerbations in spite of immunotherapy. Fatty replacement was reported in 6/19 (31.6%) patients and 0/19 (0%) controls (p = 0.02). Obvious atrophy in at least one muscle was reported in 8/19 (42.1%) patients and 1/19 (5.3%) controls (p = 0.019). Statistically significant differences between the two groups were also found in the mean total thickness, as well as in the thickness of superior recti, levator palpebrae, inferior recti, and superior oblique muscles.
Conclusion
EOM atrophy and fatty replacement were seen frequently in our series of MG patients with treatment difficulties and frequent relapses of ocular involvement.
The involvement of the right hemisphere (RH) in language, and especially after aphasia resulting from left hemisphere (LH) lesions, has been recently highlighted. The present study investigates white ...matter structure in the right hemisphere of 25 chronic post-stroke aphasic patients after LH lesions in comparison with 24 healthy controls, focusing on the four cortico-cortical tracts that link posterior parietal and temporal language-related areas with Broca’s region in the inferior frontal gyrus of the LH: the Superior Longitudinal Fasciculi II and III (SLF II and SLF III), the Arcuate Fasciculus (AF), and the Temporo-Frontal extreme capsule Fasciculus (TFexcF). Additionally, the relationship of these RH white matter tracts to language performance was examined. The patients with post-stroke aphasia in the chronic phase and the healthy control participants underwent diffusion tensor imaging (DTI) examination. The aphasic patients were assessed with standard aphasia tests. The results demonstrated increased axial diffusivity in the RH tracts of the aphasic patients. Patients were then divided according to the extent of the left hemisphere white matter loss. Correlations of language performance with radial diffusivity (RD) in the right hemisphere homologs of the tracts examined were demonstrated for the TFexcF, SLF III, and AF in the subgroup with limited damage to the LH language networks and only with the TFexcF in the subgroup with extensive damage. The results argue in favor of compensatory roles of the right hemisphere tracts in language functions when the LH networks are disrupted.
Paradoxical Reasoning: An fMRI Study Belekou, Antigoni; Papageorgiou, Charalabos; Karavasilis, Efstratios ...
Frontiers in psychology,
05/2022, Letnik:
13
Journal Article
Recenzirano
Odprti dostop
Paradoxes are a special form of reasoning leading to absurd inferences in contrast to logical reasoning that is used to reach valid conclusions. A functional MRI (fMRI) study was conducted to ...investigate the neural substrates of paradoxical and deductive reasoning. Twenty-four healthy participants were scanned using fMRI, while they engaged in reasoning tasks based on arguments, which were either Zeno's like paradoxes (paradoxical reasoning) or Aristotelian arguments (deductive reasoning). Clusters of significant activation for paradoxical reasoning were located in bilateral inferior frontal and middle temporal gyrus. Clusters of significant activation for deductive reasoning were located in bilateral superior and inferior parietal lobe, precuneus, and inferior frontal gyrus. These results confirmed that different brain activation patterns are engaged for paradoxical vs. deductive reasoning providing a basis for future studies on human physiological as well as pathological reasoning.
•Parkinson Disease (PD) and Schizophrenia (SCZ) share cortical dopamine dysfunction.•SCZ and PD were compared in a speeded decision processing task using fMRI.•Normal performance in PD contrasted ...with performance deviance in SCZ.•Cortical hypo-activity in SCZ contrasted with normal task activation in PD.•The results do not favour common cognitive/cortical dysfunction PD and SCZ.
This study examined whether Parkinson's disease (PD11Parkinson Disease) and schizophrenia (SCZ22Schizophrenia) share a hypo dopaminergic dysfunction of the prefrontal cortex leading to cognitive impairments in decision processing. 24 medicated PD patients and 28 matched controls performed the Eriksen flanker two-choice reaction time (RT33Reaction Time) task while brain activity was measured throughout, using functional Magnetic Resonance Imaging (fMRI44functional Magnetic Resonance Imaging). Results were directly compared to those of 30 SCZ patients and 30 matched controls. Significant differences between SCZ and PD were found, through directly comparing the z-score deviations from healthy controls across all behavioral measures, where only SCZ patients showed deviances from controls. Similarly a direct comparison of z-score activation deviations from controls indicated significant differences in prefrontal and cingulate cortical activation between SCZ and PD, where only SCZ patients showed hypo-activation of these areas compared to controls. The hypo-activation of the dorsolateral prefrontal cortex was related to larger RT variability (ex-Gaussian tau) in SCZ but not PD patients. Overall, the concluding evidence does not support a shared neural substrate of cognitive dysfunction, since the deficit in speeded decision processing and the related cortical hypo-activation observed in SCZ were absent in PD.
The golden standard of treating Small Cell Lung Cancer (SCLC) entails application of platinum-based chemotherapy, is often accompanied by Prophylactic Cranial Irradiation (PCI), which have been ...linked to neurotoxic side-effects in cognitive functions. The related existing neuroimaging research mainly focuses on the effect of PCI treatment in life quality and expectancy, while little is known regarding the distinct adverse effects of chemotherapy. In this context, a multimodal MRI analysis based on structural and functional brain data is proposed in order to evaluate chemotherapy-specific effects on SCLC patients. Data from 20 patients (after chemotherapy and before PCI) and 14 healthy controls who underwent structural MRI, DTI and resting state fMRI were selected in this study. From a structural aspect, the proposed analysis included volumetry and thickness measurements on structural MRI data for assessing gray matter dissimilarities, as well as deterministic tractography and Tract-Based Spatial Statistics (TBSS) on DTI data, aiming to investigate potential white matter abnormalities. Functional data were also processed on the basis of connectivity analysis, evaluating brain network parameters to identify potential manifestation of functional inconsistencies. By comparing patients to healthy controls, the obtained results revealed statistically significant differences, with the patients’ brains presenting reduced volumetry/thickness and fractional anisotropy values, accompanied by prominent differences in functional connectivity measurements. All above mentioned findings were observed in patients that underwent chemotherapy.
Objectives
Cardiac magnetic resonance (CMR) imaging is a key test in the diagnosis of cardiac amyloidosis (CA). Extracardiac involvement is common in light chain (AL) amyloidosis and MRI findings may ...assist in its diagnosis. We sought to investigate the utility of splenic CMR parameters for the diagnosis of CA.
Methods
Thirty-four patients with AL amyloidosis and 32 patients with severe left ventricular hypertrophy in the setting of aortic stenosis (LVH-AS) who completed 3T cardiac MRI at the time of their diagnosis of AL or LVH-AS were assessed with T1, T2 (modified Look-Locker inversion recovery), extracellular volume (ECV) mapping, and late gadolinium enhancement (LGE) imaging of the heart and spleen.
Results
Age, left ventricular mass index, wall thickness, ejection fraction, and splenic dimensions did not differ significantly between groups. All AL patients had cardiac involvement. T1 and T2 spleen mapping did not differ significantly between groups but AL patients had higher median ECV in the spleen than in LVH-AS (AL 46.9%, LVH-AS: 31%,
p
< 0.001), and significantly lower short tau inversion recovery ratio (AL: 1.7, LVH-AS: 2.7,
p
< 0.001) both with very good diagnostic performance to diagnose AL. We identified 16 AL patients with spleen involvement and 16 without. Spleen ECV and “normalized” spleen ratio, defined as the ratio of spleen LGE to muscle values exhibited strong correlation and had excellent diagnostic performance to discriminate those with spleen involvement.
Conclusion
Our findings show that spleen CMR parameters can identify spleen involvement in AL patients and differentiate them from those without AL amyloidosis.
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