Social and Neighborhood Context Moderates the Associations Between Processing Speed and Driving Mobility: A 10-year Analysis of the ACTIVE Study.

Objectives: Processing speed is essential to functional independence in later life, such as driving a vehicle. Few studies have examined processing speed and driving mobility in the context of racial differences and social determinants of health (SDoH). This study characterized the longitudinal association between processing speed and driving mobility, and how it varied by race and SDoH. Methods: Using data from the control arm of the Advanced Cognitive Training in Vital Elderly study (n = 581, 24.5% Black), multilevel models examined longitudinal associations between processing speed and driving mobility outcomes (driving space, exposure, and difficulty). Race and SDoH moderations were explored. Results: Decline in processing speed measures was associated with increased self-reported driving difficulty, but only for older adults with below-average to average scores for neighborhood and built environments and social community context SDoH domains. Discussion: Findings emphasize the influence of physical and social environmental characteristics on processing speed and driving mobility.

Indicators of Crash Risk in Older Adults: A Longitudinal Analysis From the ACTIVE Study.

Objective: This study aims to examine indicators of crash risk longitudinally in older adults (n = 486). Method: This study applied secondary data analyses of the 10 years of follow-up for the ACTIVE study combined with state-recorded crash records from five of the six participating sites. Cox proportional hazards models were first used to examine the effect of each variable of interest at baseline after controlling for miles driven and then to assess the three cognitive composites as predictors of time to at-fault crash in covariate-adjusted models. Results: Older age, male sex, and site location were each predictive of higher crash risk. Additionally, worse scores on the speed of processing cognitive composite were associated with higher crash risk. Discussion: Results support previous findings that both age and male sex are associated with higher crash risk. Our significant finding of site location could be attributed to the population density of our testing sites and transportation availability.

Evaluating Social Determinants of Health Domains and Their Predictive Validity Within Black/African American and White Older Adults From the ACTIVE Trial.

OBJECTIVE: To assess domains of social determinants of health (SDoH) and their associations with cognition and quality of life. METHOD: This investigation uses baseline data from individuals participating in the ACTIVE trial (n = 2505) to reproduce the SDoH domains described in Healthy People 2030 (economic stability, health care, education, neighborhood and built environment, and social and community context). Results: Results support using data from the ACTIVE trial to assess all five SDoH domains, and the ability of the composites to predict baseline performance on measures of cognition and self-reported quality of life within a sample of older adults. Additionally, higher SDoH domain scores were associated with better functioning on composite measures of cognition and higher scores for mental and general health-related quality of life with Access to Healthcare associated with all outcomes. Discussion: These findings can inform investigators interested in assessing multiple domains of SDoH and highlight the importance of access to health care within older Black/African American and White older adults.

Determination of circuit-specific morphological adaptations in ventral tegmental area dopamine neurons by chronic morphine.

Chronic opiate exposure induces neuroadaptations in the mesocorticolimbic system including ventral tegmental area (VTA) dopamine (DA) neurons, whose soma size is decreased following opiate exposure. Yet it is now well documented that VTA DA neurons are heterogeneous, with notable differences between VTA DA neurons based on their projection target. Therefore, we sought to determine whether chronic morphine induced similar changes in the morphology of VTA DA neurons that project to the nucleus accumbens (NAc) and prefrontal cortex (PFC). We utilized Cre-dependent retrograde viral vectors in DA Cre driver lines to label VTA DA neurons that projected to NAc and PFC and assessed neuronal soma size. Consistent with previous data, the soma size of VTA DA neurons that projected to the NAc medial shell was decreased following morphine exposure. However, soma size of VTA DA neurons that projected to the NAc core was unaltered by morphine. Interestingly, morphology of PFC-projecting VTA DA neurons was also altered by morphine, but in this case soma size was increased compared to sham controls. Differences in basal soma size were also noted, suggesting stable differences in projection-specific morphology in addition to drug-induced changes. Together, these data suggest morphine-induced changes in VTA DA morphology occur within distinct VTA DA populations and that study of opiate-induced structural plasticity of individual VTA DA subcircuits may be critical for understanding addiction-related behavior.

Comparison between the C-leg microprocessor-controlled prosthetic knee and non-microprocessor control prosthetic knees: a preliminary study of energy expenditure, obstacle course performance, and quality of life survey.

This study investigated energy expenditure and obstacle course negotiation between the C-leg and various non-microprocessor control (NMC) prosthetic knees and compared a quality of life survey (SF-36v2) of use of the C-leg to national norms. Thirteen subjects with unilateral limb loss (12 with trans-femoral and one with a knee disarticulation amputation) participated in the study. The mean age was 46 years, range 30-75. Energy expenditure using both the NMC and C-leg prostheses was measured at self-selected typical and fast walking paces on a motorized treadmill. Subjects were also asked to walk through a standardized walking obstacle course carrying a 4.5 kg (10 lb) basket and with hands free. Finally, the SF-36v2 was completed for subjects while using the C-leg. Statistically significant differences were found in oxygen consumption between prostheses at both typical and fast paces with the C-leg showing decreased values. Use of the C-leg resulted in a statistically significant decrease in the number of steps and time to complete the obstacle course. Scores on a quality of life index for subjects using the C-leg were above the mean for norms for limitation in the use of an arm or leg, equal to the mean for the general United States population for the physical component score and were above this mean for the mental component score. Based on oxygen consumption and obstacle course findings, the C-leg when compared to the NMC prostheses may provide increased functional mobility and ease of performance in the home and community environment. Questionnaire results suggest a minimal quality of life impairment when using a C-leg for this cohort of individuals with amputation.