Articles: amyotrophic-lateral-sclerosis-pathology.
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The extensive application of advanced MR imaging techniques has undoubtedly improved our knowledge of the pathophysiology of amyotrophic lateral sclerosis. Nevertheless, the precise extent of neurodegeneration throughout the central nervous system is not fully understood. In the present study, we assessed the spatial distribution of cortical damage in amyotrophic lateral sclerosis by using a cortical thickness measurement approach. ⋯ Cortical thinning of the motor cortex might reflect upper motor neuron impairment, whereas the extramotor involvement seems to be related to disease disability, progression, and duration. The cortical pattern of neurodegeneration depicted resembles what has already been described in frontotemporal dementia, thereby providing further structural evidence of a continuum between amyotrophic lateral sclerosis and frontotemporal dementia.
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Diffusion-weighted magnetic resonance imaging (DWMRI) is used to study white matter (WM) in normal and clinical populations. In DWMRI studies, diffusion tensor imaging (DTI) models the WM anisotropy with one dominant direction, detecting possible pathway abnormalities only in large and highly coherent fiber tracts. However, more general anisotropy models like Q-ball imaging (QBI) may provide more sensitive WM descriptors in single patients. ⋯ Particularly, the left corticospinal tracts resulted more markedly depicted by the QBI than by the DTI model, with GFA predicting ALS disability better than FA. The present findings demonstrate that QBI model is suitable for studying WM tract degeneration in population-level clinical studies. Particularly, group-level studies of fiber integrity may benefit from QBI when DTI is biased towards low values, such as in cases of fiber degeneration, and in regions with more than one dominant fiber direction.
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Journal of neurology · Feb 2014
Regional alterations in cortical thickness and white matter integrity in amyotrophic lateral sclerosis.
Previous neuroimaging studies have revealed that both gray matter (GM) and white matter (WM) are altered in several morphological aspects in amyotrophic lateral sclerosis (ALS). However, the relations between GM and WM measures and their contributions to clinical features remain in doubt. In this study, we acquired high-resolution diffusion tensor imaging along with structural magnetic resonance imaging data on 20 patients with clinical evidence of ALS and 21 matched healthy controls. ⋯ Finally, patients with faster clinical progression showed more severe cortical thinning of the left precentral gyrus and FA reduction of the left CST. Together, these findings suggest that ALS is multisystem degeneration involving both the widespread cortices and the underlying WM fibers. GM and WM changes might play distinct roles in the disease progression.
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Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease affecting the motor system. Although the etiology of the disease is not fully understood, microglial activation and neuroinflammation are thought to play a role in disease progression. ⋯ This study suggests that the increase in spinal cord microglia occurs around and after disease onset and is preceded by cellular pathology. The results show that Arg1 and iNOS, thought to have opposing inflammatory properties, are upregulated in microglia during disease progression and that Arg1 in motor neurons may confer protection from disease processes. Further understanding of the neuroinflammatory response, and the Arg1/iNOS balance in motor neurons, may provide suitable therapeutic targets for ALS.
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J. Neurol. Neurosurg. Psychiatr. · Jan 2014
Spreading of amyotrophic lateral sclerosis lesions--multifocal hits and local propagation?
To investigate whether or not the lesions in sporadic amyotrophic lateral sclerosis (ALS) originate from a single focal onset site and spread contiguously by prion-like cell-to-cell propagation in the rostrocaudal direction along the spinal cord, as has been hypothesised (the 'single seed and simple propagation' hypothesis). ⋯ In sporadic ALS, the distribution of lower motoneuron involvement cannot be explained by the 'single seed and simple propagation' hypothesis alone. We propose a 'multifocal hits and local propagation' hypothesis instead.