Study On Cognitive Impairment Of Amyotrophic Systolic Sclerosis By Nuclear Magnetic Resonance Imaging

Background:Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder characterized by progressive degeneration of both upper and lower motor neurons, with also extramotor systems involved in some patients. Cognitive impairment is common in ALS, however, diagnosis of the subtype depends mainly on neuropsychological assessment which is both complicated and time-consuming. Neuroimaging is noninvasive, efficient and allows dynamic observation in vivo which has superiority on related studies over other auxiliary examinations.Objective:Explore specific imaging changes related to cognitive impairment in ALS on both structural and functional aspects using magnetic resonance imaging (MRI) in order to uncover potential pathophysiological mechanism and provide valuable reference for clinical application of MRI in ALS diagnosis and treatment in the future.Methods:16 ALS patients were enrolled and divided into two groups by the presence or absence of cognitive impairment (ALSi & ALSu). (1) Routine MRI structural images, resting-state functional MRI and diffusion tensor imaging data were collected for comparison between groups through voxel-based morphometry (VBM)、regional homogeneity (ReHo)、amplitude of low-frequency fluctuation (ALFF)、voxel-based analysis (VBA) and atlas-based analysis (ABA) methods. (2) Analyze functional connectivity (FC) with regions of interest which showed significant differences in ReHo analysis as seeds. (3) This study also includes correlation analysis of voxels in gray matter density map/ALFF map/szReHo map and results of several neuropsychological tests.Results:(1) VBM analysis showed no significant differences in both gray matter and white matter density between the two groups; correlation analysis showed gray matter density was negatively correlated to cognitive function. (2) ALFF analysis showed significant increased signals in widespread areas of bilateral cerebrum and cerebellum in ALSi group compared to ALSu group; receiver operating characteristic curve analysis showed the diagnostic value of 3.05 as a cutoff of ALFF was the highest for detection of cognitive impairment in ALS; correlation analysis showed ALFF value was also negatively correlated to cognitive function. (3) ReHo analysis showed both significant increased and decreased signals in different areas and the same was with correlation analysis. (4) FC analysis showed significant increased FC between most seeds and regional areas in ALSi group compared to ALSu group; two possible seeds for reconstruction of default mode network (DMN) nodes were discovered; the established hypothesis of ReHo analysis was successfully verified. (5) DTI analysis showed significant increased FA in both gray matter and white matter.Conclusion:ALS may be a complicated clinical continuum which involves multiple systems other than motor system. There is sophisticated structural and functional plasticity for cognitive impairment in ALS. MRI proves to be an irreplaceable tool on related studies which can provides some evidence for further discussion on its pathogenesis.