Theses and Dissertations

The aim of this study was to explore cross-sectional and longitudinal aging differences in immediate and delayed visual and verbal memory abilities in individuals with Autism Spectrum Disorder (ASD) compared with neurotypicals (NTs). We measured hippocampal size, fornix fractional anisotropy (FA), and hippocampal and fornix freewater to understand how aging impacts memory structures. Longitudinal findings highlight vulnerabilities in immediate verbal memory and hippocampal volume, while cross-sectional findings indicate fornix freewater may increase at a faster rate in adults with ASD. Future research will examine cognitive and structural sex differences and will study how cognitive measures correlate with structural measures.

Parkinson’s Disease (PD) is characterized by involuntary tremors, muscle rigidity, slowed movement, and cognitive impairments. Some people with PD experience “Freezing of Gait” (FOG), which is an acute inability to release effective stepping. The severity of Freezing of Gait can be influenced by disease duration, disease severity, and medication. Freezing of Gait can lead to an increased risk of falls, mood disorders, reduced quality of life, poorer cognition, and executive function impairments (Morris et. al.). It is important to understand how Freezing of Gait can affect cognition, as this can alter the plan of cognitive rehabilitation that the patient receives in order to improve their cognition. Within each of these domains, are a variety of tests that all claim to measure the same cognition the same way and achieve similar results. A recent meta analysis assessed this hypothesized effect. However, to best understand this relationship, it is important to assess whether the effects of FOG status on cognition are similar across cognitive tests of the same domain. This research was performed by using a previously completed meta analysis on PD tests and the domains that tests fall into. Each of the domains were analyzed individually, and the most common tests used within each domain were compared to determine their effect sizes. The effect sizes were then compared to determine which tests have a greater influence on cognition, and if the effect sizes of each test within the same domain are similar, showing that FOG affects cognition to a similar degree.