Matching Items (2)

The Differences in the Motor Abilities of Individuals with Autism Spectrum Disorder (ASD) and Neurotypical (NT) Individuals

Description

Introduction: Autism Spectrum Disorder (ASD) is a lifelong neurodevelopmental disorder that increased in prevalence in the last few decades, most notably among older adults. The gap in knowledge of aging processes, among individuals with ASD, and the increasing prevalence of Parkinsonism diagnosis in this population, revealed a need for research…

Introduction: Autism Spectrum Disorder (ASD) is a lifelong neurodevelopmental disorder that increased in prevalence in the last few decades, most notably among older adults. The gap in knowledge of aging processes, among individuals with ASD, and the increasing prevalence of Parkinsonism diagnosis in this population, revealed a need for research efforts. Nevertheless, differences in the group and age-related differences in cortical thickness in brain regions associated with motor control remain relatively unexplored. Objective: In this study, we analyzed cross-sectional data to investigate group differences and age-related differences in cortical thickness of the left hemisphere (lh) and right hemisphere (rh) of the precentral gyrus and paracentral lobule, in adults with ASD vs. NT adults. Knowing that individuals with ASD present greater group and age-related motor impairments than NT individuals, we tested the following hypothesis: adults with ASD will demonstrate reduced cortical thickness and greater relationships between increasing age and decreasing cortical thickness in the precentral gyrus and paracentral lobule than the NT participants. Methods: Group and age-related differences in cortical thickness were analyzed in our cohort of 191 participants with (N=105; ages 18-71) and without ASD (N=86 ages 18-70). T1-weighted MRI images were collected from each participant and were analyzed using FreeSurfer to obtain cortical thickness measurements from the motor regions of interest. Using SPSS (IBM SPSS Statistics for macOs, Version 28.0.1.1) univariate general linear models were used to test the between-subject effects of group, age, and group by age interaction, with sex as a covariate. Results: A statistically significant effect of the diagnosis group on cortical thickness was only observed in the lh precentral gyrus, with the ASD group showing a thinner cortex than the NT group. A statistically significant group-by-age interaction was present in the cortical thickness of the lh precentral gyrus, the rh precentral gyrus, and the lh paracentral lobule. For each interaction, the relationship between age and cortical thickness had a steeper negative slope in the ASD group compared to the NT group. Discussion: Consistent with our hypothesis, findings indicate ASD affects cortical thickness and may be linked to greater age-related reduced cortical thickness, of the studied motor areas, in adults with ASD compared to NT adults. Future research is warranted to investigate the relationship between cortical thickness in motor regions and the severity of motor impairments in the ASD population. Further longitudinal investigations of the age-related changes (trajectories) in cortical thickness, specific to motor regions, in individuals with ASD, are also necessary.
ContributorsValdez, Melony (Author) / Braden, Brittany (Thesis director) / Ofori, Edward (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)
Created2023-05
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Compensation or Pre-stroke Advantage? An Investigation of the Relationships Between Structural and Diffusion MRI Measures in the Right Hemisphere and Language and Cognitive Abilities in Left-hemisphere Stroke Survivors

Description
Previous work indicates that structural changes in the right hemisphere following left hemisphere stroke may be related to language abilities. However, the mechanisms behind this relationship remain unclear, particularly regarding the relative contributions of gray and white matter. The present study examined how structural and diffusion measures in the right…

Previous work indicates that structural changes in the right hemisphere following left hemisphere stroke may be related to language abilities. However, the mechanisms behind this relationship remain unclear, particularly regarding the relative contributions of gray and white matter. The present study examined how structural and diffusion measures in the right hemisphere differ between chronic left hemisphere stroke survivors and matched control subjects, and the relationships between language and cognition measures and these right hemisphere measures. T1-weighted MRI, diffusion tensor images (DTI), and a battery of cognitive tests were obtained from 27 chronic left hemisphere stroke survivors and 44 neurologically intact matched control participants. Cortical and volumetric measures of gray and white matter in regions of interest were obtained from the T1 images and compared between groups, and correlated with behavioral measures. Tract-Based Spatial Statistics and tractography methods from the DTI were examined in a similar manner. The T1 MRI-based analyses revealed that the stroke survivors did not differ from the control group in any of the gray or white matter volume measurements. The cortical thickness and mean curvature analyses identified right lateral frontal and insular ROIs exhibiting thinner and greater curvature (an indication of atrophy) in the left hemisphere stroke survivors compared to controls. The DTI-based results showed that the stroke survivors had lower fractional anisotropy and fewer reconstructed fibers in the right language ventral-stream tracts. Regarding correlations between the right hemisphere measures and behavioral performance, there were no significant results within the DTI data, and only one significant result in the gray matter analyses: faster processing speed was correlated with greater cortical thickness in the right frontal cortex in chronic left hemisphere stroke survivors. Overall, the present study provides support for the idea that the right hemisphere exhibits post-stroke changes, particularly in right dorsal stream gray matter and the ventral stream’s white matter, and that these differences are not captured by T1-imaging alone; in fact, the DTI tract-specific analyses were perhaps the most revealing. Future studies are needed, perhaps incorporating functional neuroimaging, to elucidate how these right hemisphere differences in left hemisphere stroke survivors is related to language recovery.
ContributorsHsueh, Yi-Ting (Author) / Reddy, Corianne (Thesis advisor) / Braden, Brittany (Committee member) / Schaefer, Sydney (Committee member) / Arizona State University (Publisher)
Created2021