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.
Methods: The study consisted of 79 participants with ASD (59 male, 20 female; ages 18-70, mean=40.27 [±17] years) and 77 NT participants (46 male, 31 female; ages 18-71, mean=40.33 [±16] years). Hippocampal and fornix FW and FA values were generated from diffusion tensor images obtained along 32 directions using a b-value of 2500 s/mm2 in the axial direction with 3 mm slice resolution. These images were then processed for eddy current, distortion, b-vec and motion correction, skull stripped, and non-linear registered using Advanced Normalization Tools (ANTs) to the subject’s T1 image. FW and FA maps were calculated using custom written MatLab code and standard atlases containing the hippocampus and fornix were applied.
Results: The right hippocampus showed a significant diagnosis by age interaction (p=0.018), such that the increase in FW with age was greater for adults with ASD. The left hippocampus diagnosis by age interaction approached significance (p=0.055). Similarly, the right fornix showed a significant diagnosis by age interaction (p=0.044), with increases in FW with age as greater for adults with ASD, and the left fornix diagnosis by age interaction approached significance (p=0.053). FA values showed no significant diagnosis by age interactions.
Conclusion: In the hippocampus and fornix, the association between increasing FW and increasing age was more pronounced for adults with ASD than matched NT adults. This may mean that as adults with ASD age, these regions will degenerate faster than their NT peers, which could have implications for accelerated age-related memory decline. However, a notable limitation is the cross-sectional nature of the study. Our ongoing longitudinal study will inform a more definitive picture of brain aging with ASD.
Inflammatory genes are known to only show in African Americans and non-Hispanic Whites. The objective of this study was to observe the correlation from the obtained data of the prevalence of the APOE ε4 genotype. We examined cerebral free-water, a marker of neuroinflammation, hippocampal volume, and volume of white-matter hyperintensities in African Americans (AA) and non-Hispanic Whites who were categorized in groups based on whether they had APOE ε4 allele or not. AA had lower prevalence of APOE e4 genotype than non-Hispanic Whites. AA groups have a slightly higher hippocampal volume compared to the Non-Hispanic White (NHW) groups. African Americans also reported increased white-matter hyperintensities and cerebral free-water. Hippocampal atrophy is associated with Alzheimer's disease, this might suggest that the AA groups have a lower risk of Alzheimer's, although further research is needed to confirm this relationship. Lastly, our findings also suggest other potential socioeconomic factors that could contribute to increased incidence of dementia among AA and potential resilience factors early in the course of Alzheimer’s disease process.
Research has shown the benefits of exercise on people with (DS), and how it affects their quality of life (Maïano et al. 2019). However, many studies have also shown that the majority of people with DS do not meet the national minimum requirements for physical activity per day (Phillips et al. 2011). The current study will focus on Pediatric Assisted Cycle Therapy (PACT) as exercise and specifically its effects on children with DS. The goal is to improve the general behavioral skills of children with DS, which in turn can improve their quality of life. We predict that, based on pilot data (Gomez, 2015; Parker, 2016), GLTEQ will increase their total activity score following 8 weeks of PACT in young children with DS. The Godin Leisure Time Exercise Questionnaire was used to measure the participants’ participation levels in leisure time activity. Participants were involved in an 8-week intervention, in which they biked (PACT) for 30 minutes, twice a week. GLETQ was measured pre and post intervention and assessed using the scale provided by the GLETQ. The data from this study has shown a positive correlation between Leisure Time Activity and PACT. Overall, a mean increase in raw activity score in the GLETQ was shown.