Measurement of synaptic density in Down syndrome using PET imaging: a pilot study.

Down syndrome (DS) is the most prevalent genetic cause of intellectual disability, resulting from trisomy 21. Recently, positron emission tomography (PET) imaging has been used to image synapses in vivo. The motivation for this pilot study was to investigate whether synaptic density in low functioning adults with DS can be evaluated using the PET radiotracer [11C]UCB-J. Data were acquired from low functioning adults with DS (n = 4) and older neurotypical (NT) adults (n = 37). Motion during the scans required the use of a 10-minute acquisition window for the calculation of synaptic density using SUVR50-60,CS which was determined to be a suitable approximation for specific binding in this analysis using dynamic data from the NT group. Of the regions analyzed a large effect was observed when comparing DS and NT hippocampus and cerebral cortex synaptic density as well as hippocampus and cerebellum volumes. In this pilot study, PET imaging of [11C]UCB-J was successfully completed and synaptic density measured in low functioning DS adults. This work provides the basis for studies where synaptic density may be compared between larger groups of NT adults and adults with DS who have varying degrees of baseline cognitive status.

Characterizing Objective Quality of Life and Normative Outcomes in Adults with Autism Spectrum Disorder: An Exploratory Latent Class Analysis.

This study aims to extend the definition of quality of life (QoL) for adults with autism spectrum disorder (ASD, n = 180, ages 23-60) by: (1) characterizing the heterogeneity of normative outcomes (employment, independent living, social engagement) and objective QoL (physical health, neighborhood quality, family contact, mental health issues); and (2) identifying predictors of positive normative outcomes and good objective QoL. Findings of an exploratory latent class analysis identified three groups of adults with ASD-Greater Dependence, Good Physical and Mental Health, and Greater Independence. Findings indicate that better daily living skills, better executive function, and more maternal warmth are associated with assignment to better outcome groups. Findings have implications for interventions designed to enhance achievement of normative outcomes and objective QoL.

Evaluation of an activities of daily living scale for adolescents and adults with developmental disabilities.

BACKGROUND: Activity limitations are an important and useful dimension of disability, but there are few validated measures of activity limitations for adolescents and adults with developmental disabilities. OBJECTIVE/HYPOTHESIS: To describe the development of the Waisman Activities of Daily Living (W-ADL) Scale for adolescents and adults with developmental disabilities, and systematically evaluate its measurement properties according to an established set of criteria. METHODS: The W-ADL was administered among four longitudinally studied groups of adolescents and adults with developmental disabilities: 406 with autism; 147 with fragile-X syndrome; 169 with Down syndrome; and 292 with intellectual disability of other or unknown origin. The W-ADL contains 17 activities and each is rated on a 3-point scale (0 = "does not do at all", 1 = "does with help", 2 = "independent"), and a standard set of criteria were used to evaluate its measurement properties. RESULTS: Across the disability groups, Cronbach's alphas ranged from 0.88 to 0.94, and a single-factor structure was most parsimonious. The W-ADL was reliable over time, with weighted kappas between 0.92 and 0.93. Criterion and construct validity were supported through substantial associations with the Vineland Screener, need for respite services, caregiving burden, and competitive employment. No floor or ceiling effects were present. There were significant group differences in W-ADL scores by maternally reported level of intellectual disability (mild, moderate, severe, profound). CONCLUSIONS: The W-ADL exceeded the recommended threshold for each quality criterion the authors evaluated. This freely available tool is an efficient measure of activities of daily living for surveys and epidemiological research concerning adolescents and adults with developmental disabilities.