Measuring Presence in Virtual Environments: A Survey

The effectiveness of a virtual reality experience is strongly affected by the sense of presence of the users involved. This article reviews the different definitions of presence and the main proposed methods to measure it through the analysis of 1,214 papers published in the past 30 years. From the analysis of 239 user studies, we found that 85.8% used subjective measures, 11.7% used a combination of subjective and objective measures, while 2.5% used only objective measures. We also identified, from the studies reviewed, 29 main factors to evoke presence in virtual environments, grouped into four categories: Engagement, Personal Characteristics, Interaction Fidelity, and Display Fidelity.

What is in the toolkit (and what are the tools)? How to approach the study of doctor–patient communication

Doctor–patient communication is important, but is challenging to study, in part because it is multifaceted. Communication can be considered in terms of both the aspects of the communication itself, and its measurable effects. These effects are themselves varied: they can be proximal or distal, and can focus on subjective measures (how patients feel about communication), or objective measures (exploring more concrete health outcomes or behaviours). The wide range of methodologies available has resulted in a heterogeneous literature which can be difficult to compare and analyse.Here, we provide a conceptual approach to studying doctor–patient communication, examining both variables which can controlled and different outcomes which can be measured. We present methodologies which can be used (questionnaires, semistructured interviews, vignette studies, simulated patient studies and observations of real interactions), with particular emphasis on their respective logistical advantages/disadvantages and scientific merits/limitations. To study doctor–patient communication more effectively, two or more different study designs could be used in combination.We have provided a concise and practically relevant review of the methodologies available to study doctor–patient communication to give researchers an objective view of the toolkit available to them: both to understand current research, and to conduct robust and relevant studies in the future.

Subjective Measures of Workload and Sleep in Australian Army Recruits; Potential Utility as Monitoring Tools

ABSTRACT Introduction Subjective measures may offer practitioners a relatively simple method to monitor recruit responses to basic military training (BMT). Yet, a lack of agreement between subjective and objective measures may presents a problem to practitioners wishing to implement subjective monitoring strategies. This study therefore aims to examine associations between subjective and objective measures of workload and sleep in Australian Army recruits. Materials and Methods Thirty recruits provided daily rating of perceived exertion (RPE) and differential RPE (d-RPE) for breathlessness and leg muscle exertion each evening. Daily internal workloads determined via heart rate monitors were expressed as Edwards training impulse (TRIMP) and average heart rate. External workloads were determined via global positioning system (PlayerLoadTM) and activity monitors (step count). Subjective sleep quality and duration was monitored in 29 different recruits via a customized questionnaire. Activity monitors assessed objective sleep measures. Linear mixed-models assessed associations between objective and subjective measures. Akaike Information Criterion assessed if the inclusion of d-RPE measures resulted in a more parsimonious model. Mean bias, typical error of the estimate (TEE) and within-subject repeated measures correlations examined agreement between subjective and objective sleep duration. Results Conditional R2 for associations between objective and subjective workloads ranged from 0.18 to 0.78, P < 0.01, with strong associations between subjective measures of workload and TRIMP (0.65–0.78), average heart rate (0.57–0.73), and PlayerLoadTM (0.54–0.68). Including d-RPE lowered Akaike Information Criterion. The slope estimate between objective and subjective measures of sleep quality was not significant. A trivial relationship (r = 0.12; CI −0.03, 0.27) was observed between objective and subjective sleep duration with subjective measures overestimating (mean bias 25 min) sleep duration (TEE 41 min). Conclusions Daily RPE offers a proxy measure of internal workload in Australian Army recruits; however, the current subjective sleep questionnaire should not be considered a proxy measure of objective sleep measures.

Prescription Medications and Co-Morbidities in Late Middle-Age are Associated with Greater Cognitive Declines: Results from WRAP

The present study investigated: 1) sex differences in polypharmacy, comorbidities, self-rated current health (SRH), and cognitive performance, 2) associations between comorbidities, polypharmacy, SRH, and objective measures of health, and 3) associations of these factors with longitudinal cognitive performance. Analyses included 1039 eligible Wisconsin Registry for Alzheimer’s Prevention (WRAP) participants who were cognitively unimpaired at baseline and had ≥2 visits with cognitive composites, self-reported health history, and concurrent medication records. Repeated measures correlation (rmcorr) examined the associations between medications, co-morbidities, SRH, and objective measures of health (including LIfestyle for BRAin Health Index (LIBRA), and depression). Linear mixed-effect models examined associations between medications, co-morbidities, and cognitive change over time using a preclinical Alzheimer’s cognitive composite (PACC3) and cognitive domain z-scores (executive function, working memory, immediate learning, and delayed recall). In secondary analyses, we also examined whether the number of medications interacted with co-morbidities and whether they modified age-related cognitive trajectories. The number of prescribed medications was associated with worse SRH and a higher number of self-reported co-morbidities. More prescribed medications were associated with a faster decline in executive function, and more comorbidities were associated with faster PACC3 decline. Those with a non-elevated number of co-morbidities and medications performed an average of 0.26 SD higher (better) in executive function and an average of 0.18 SD higher on PACC3 than those elevated on both. Associations between medications, co-morbidities, and executive function, and PACC3 suggest that persons with more co-morbidities and medications may be at increased risk of reaching clinical levels of impairment earlier than healthier, less medicated peers.

Methods and Rationale for Using GPS-Derived Objective Technologies to Examine Community Mobility in Older Adults

Objective measures of community mobility are advantageous for capturing life-space activity. In contrast to subjective, self-reported approaches, GPS-derived objective measures leverage passive, real-time data collection techniques to mitigate recall bias and minimize participant burden. We present methods to quantify community mobility among a sample of 164 community-dwelling older adults (Mean age=77.3±6.5) from a physical therapy intervention aimed at improving walking ability. We characterized community mobility using activity space metrics (e.g., standard deviation ellipse (SDE) area), timing (e.g., time outside home), and shape (e.g., SDE compactness). We will discuss challenges and solutions to generating these metrics as well as their associations with physical and cognitive performance. Time outside of home and SDE area, but not SDE compactness, were correlated with better performance on the 6-Minute Walking Test and Trail-Making Test (Part B) (ρ=.20-.23, p’s<.05). These findings will aid in understanding which community mobility measures are associated with functional capacity.

Community Mobility in Older Adults: Novel Methodologies, Risk Factors, and Interventions

Community mobility is an individual’s movement outside the home. It is essential for the completion of many instrumental activities of daily living, such as shopping and healthcare, and promotes physical function, social engagement, independent living, and quality of life. Mobility research often focuses on gait speed measured in clinical settings, a critical but not sufficient determinant of community mobility. Here we present four talks that assess community mobility and its determinants using novel methodologies to enhance our understanding of how to maintain independence in older ages. First, Andrea Rosso presents characteristics of individuals with the strongest associations between environmental walkability, as assessed by virtual audits, and walking. Second, Kyle Moored demonstrates associations of self-reported fatigability with life space among older men, independent of their physical functioning. Breanna Crane introduces GPS-based objective measures of community mobility and their associations with cognitive and physical function of older adults. Finally, Pam Dunlap presents results of a randomized clinical trial of a physical therapy intervention to improve walking in older adults on subjective and objective measures of life space. These talks will provide a better understanding of the factors related to community mobility, introduce attendees to novel methodologies in the assessment of both community mobility and risk factors associated with the loss of community mobility, and demonstrate approaches to improve community mobility in at-risk older adults. The discussant, Jana Hirsch, will provide perspectives on how these data inform our current view of community mobility and will lead a discussion with the audience.