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1. Do Simulated Augmented Reality Overlays Influence Street-Crossing Decisions for Non-Mobility-Impaired Older and Younger Adult Pedestrians?

   https://doi.org/10.1177/00187208231151280  

   Malik, Jeehan ; Kim, Nam-Yoon ; Parr, Morgan D. N. ; Kearney, Joseph K. ; Plumert, Jodie M. ; Rector, Kyle ( January 2023 , Human Factors: The Journal of the Human Factors and Ergonomics Society)

   This study used a virtual environment to examine how older and younger pedestrians responded to simulated augmented reality (AR) overlays that indicated the crossability of gaps in a continuous stream of traffic.

   Older adults represent a vulnerable group of pedestrians. AR has the potential to make the task of street-crossing safer and easier for older adults.

   We used an immersive virtual environment to conduct a study with age group and condition as between-subjects factors. In the control condition, older and younger participants crossed a continuous stream of traffic without simulated AR overlays. In the AR condition, older and younger participants crossed with simulated AR overlays signaling whether gaps between vehicles were safe or unsafe to cross. Participants were subsequently interviewed about their experience.

   We found that participants were more selective in their crossing decisions and took safer gaps in the AR condition as compared to the control condition. Older adult participants also reported reduced mental and physical demand in the AR condition compared to the control condition.

   AR overlays that display the crossability of gaps between vehicles have the potential to make street-crossing safer and easier for older adults. Additional research is needed in more complex real-world scenarios to further examine how AR overlays impact pedestrian behavior.

   With rapid advances in autonomous vehicle and vehicle-to-pedestrian communication technologies, it is critical to study how pedestrians can be better supported. Our research provides key insights for ways to improve pedestrian safety applications using emerging technologies like AR.

    

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2. Cardiorespiratory fitness, hippocampal subfield volumes, and mnemonic discrimination task performance in aging

   https://doi.org/10.1002/hbm.25259  

   Kern, Kathryn L. ; Storer, Thomas W. ; Schon, Karin ( December 2020 , Human Brain Mapping)

   Aging and exercise have opposing effects on mnemonic discrimination task performance, which putatively taxes pattern separation mechanisms reliant on the dentate gyrus (DG) subfield of the hippocampus. In young adults, increasing cardiorespiratory fitness (CRF) has been shown to improve mnemonic discrimination task performance and increase left anterior DG/CA3 volume. It is unknown how these variables interact in cognitive aging, yet this knowledge is critical, given the established effects of aging on hippocampal plasticity. To investigate these relationships, 65 older adults (aged 55–85 years) completed a submaximal treadmill test to estimate CRF, a mnemonic discrimination task, and a high‐resolution MRI scan to determine hippocampal subfield volumes. Our older adult sample demonstrated the lowest task accuracy in the condition with the greatest stimuli similarity and left DG/CA3 body volume significantly predicted accuracy in this condition. Our results did not provide support for relationships between CRF and task accuracy or CRF and DG/CA3 volume as evidenced in studies of young adults. Instead, CRF predicted bilateral subiculum volume in older adult women, not men. Altogether, these findings provide further support for a role of the DG in behavioral pattern separation in humans and suggest that CRF may have differential effects on hippocampal subfield integrity in older adult men and women.ClinicalTrials.govidentifiers: (a) Neuroimaging Study of Exercise and Memory Function, NCT02057354; (b) The Entorhinal Cortex and Aerobic Exercise in Aging, NCT02775760; (c) Physical Activity and Cognition Study, NCT02773121.

    

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3. Examination of Diffusion Patterns of Tornado Warning Using an Agent-Based Model and Simulation

   https://doi.org/10.1175/WCAS-D-21-0089.1  

   Liang, Daan ; Cong, Zhen ; Cao, Guofeng ( April 2022 , Weather, Climate, and Society)

   Timely communication of warnings is essential to protection of lives and properties during tornado outbreaks. Both official and personal channels of communication prove to have considerable impact on the overall outcome. In this study, an agent-based model is developed to simulate warning’s reception–dissemination process in which a person is exposed to, receives, and sends information while interacting with others. The model is applied to an EF5 tornado (EF indicates enhanced Fujita scale) that struck Moore, Oklahoma, in 2013. The parameters are calibrated using publicly available data or a poststorm telephone survey or were derived from literature reviews, expert judgement, and sensitivity analysis. The result shows a reasonable agreement between modeled and observed reception rates for older and younger adults and for different channels, with errors of less than 20 percentage points. Similar agreement is also seen for the average numbers of warning sources. The subsequent simulation indicates that, in the absence of tornado sirens, the overall reception rates for younger and older adults would drop from the baseline by 17 and 6 percentage points, respectively. Concurrently, there is a large decline in the number of warning sources. When a persons’ social network is enlarged, the reception rate for older adults improves from 77% to 80%, whereas for younger adults it stays unchanged. The impact of increased connectivity is more pronounced when people are not watching television or a tornado siren is not available.

   Every year, tornadoes cause significant property damage and numerous casualties in the United States. This study aims to understand how tornado warnings reach the at-risk public through various communication channels. Using the agent-based model and simulation, we are able to reconstruct the dynamic patterns of warning’s reception–dissemination process for older and younger adults within a historical EF5 tornado. Further analysis confirms the importance of tornado sirens in not only alerting more residents about the dangerous weather condition but also prompting protective actions. In the meantime, an increase in social connectivity among residents would compensate for the lack of exposure to television and tornado siren. Future work should investigate the robustness of this model and its parameters when applied to other tornado outbreaks.

    

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4. Optimizing exoskeleton assistance to improve walking speed and energy economy for older adults

   https://doi.org/10.1186/s12984-023-01287-5  

   Lakmazaheri, Ava ; Song, Seungmoon ; Vuong, Brian B. ; Biskner, Blake ; Kado, Deborah M. ; Collins, Steven H. ( January 2024 , Journal of NeuroEngineering and Rehabilitation)

   Walking speed and energy economy tend to decline with age. Lower-limb exoskeletons have demonstrated potential to improve either measure, but primarily in studies conducted on healthy younger adults. Promising techniques like optimization of exoskeleton assistance have yet to be tested with older populations, while speed and energy consumption have yet to be simultaneously optimized for any population.

   We investigated the effectiveness of human-in-the-loop optimization of ankle exoskeletons with older adults. Ten healthy adults > 65 years of age (5 females; mean age: 72 ± 3 yrs) participated in approximately 240 min of training and optimization with tethered ankle exoskeletons on a self-paced treadmill. Multi-objective human-in-the-loop optimization was used to identify assistive ankle plantarflexion torque patterns that simultaneously improved self-selected walking speed and metabolic rate. The effects of optimized exoskeleton assistance were evaluated in separate trials.

   Optimized exoskeleton assistance improved walking performance for older adults. Both objectives were simultaneously improved; self-selected walking speed increased by 8% (0.10 m/s;p = 0.001) and metabolic rate decreased by 19% (p = 0.007), resulting in a 25% decrease in energetic cost of transport (p = 8e-4) compared to walking with exoskeletons applying zero torque. Compared to younger participants in studies optimizing a single objective, our participants required lower exoskeleton torques, experienced smaller improvements in energy use, and required more time for motor adaptation.

   Our results confirm that exoskeleton assistance can improve walking performance for older adults and show that multiple objectives can be simultaneously addressed through human-in-the-loop optimization.

    

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5. High levels of objectively measured physical activity across adolescence and adulthood among the Pokot pastoralists of Kenya

   https://doi.org/10.1002/ajhb.23205  

   Sayre, M. Katherine ; Pike, Ivy L. ; Raichlen, David A. ( December 2018 , American Journal of Human Biology)

   Levels of physical activity (PA) across the lifespan are important predictors of physical fitness, impacting individual health, and longevity. Individuals living in industrialized societies are often characterized as more sedentary than those who live in small‐scale societies, and this inactivity is generally linked with increased incidence of chronic disease, especially during aging. However, less empirical data exist regarding levels and patterns of PA across the lifespan among small‐scale societies compared with industrialized societies. The goal of this study was to characterize PA among the Pokot pastoralists of rural northern Kenya.

   PA was measured in 40 participants ranging in age from 14 to 78 years using ActiGraph wrist‐worn accelerometers. Wear time spanned 24–77 hours, with a modal wear time of 50 hours.

   We show that the Pokot spend large amounts of time in moderate‐to‐vigorous physical activity (MVPA), achieving an average of 99.14 ± 7.25 minutes per day in MVPA. Males and younger participants tended to spend more time in MVPA. However, older participants were still physically active and engaged in over 50 minutes per day of MVPA.

   The Pokot are highly physically active from adolescence through adulthood. Other pastoralist groups may display a similar pattern of PA. During human evolution, lifespans increased, and lifestyles were characterized by a relatively high level of physical activity. The human aging process may be adapted for activity throughout life, and lifelong activity may have played an important role in increases in human longevity during evolution.

    

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