Mattias Wallergård

Inducing physiological stress recovery with sounds of nature in a virtual reality forest — Results from a pilot study

Experimental research on stress recovery in natural environments is limited, as is study of the effect of sounds of nature. After inducing stress by means of a virtual stress test, we explored physiological recovery in two different virtual natural environments (with and without exposure to sounds of nature) and in one control condition. Cardiovascular data and saliva cortisol were collected. Repeated ANOVA measurements indicated parasympathetic activation in the group subjected to sounds of nature in a virtual natural environment, suggesting enhanced stress recovery may occur in such surroundings. The group that recovered in virtual nature without sound and the control group displayed no particular autonomic activation or deactivation. The results demonstrate a potential mechanistic link between nature, the sounds of nature, and stress recovery, and suggest the potential importance of virtual reality as a tool in this research field.

Cardiovascular and cortisol reactivity and habituation to a virtual reality version of the Trier Social Stress Test: A pilot study

The Trier Social Stress Test (TSST) is a widely used protocol to induce stress in laboratory settings. Briefly, in the TSST, the test participant is asked to hold a speech and to do an arithmetic task in front of an audience. In the present pilot study, we examined endocrine and autonomic reactivity and habituation to repeated stress provocations using a virtual reality (VR) version of TSST. The VR system was a CAVE™ system with three rear projected walls (4 m×3 m), and one floor projection. The system also included a head tracking system and passive stereoscopy. The virtual audience consisted of one woman, and two men. Ten healthy men, mean age 28.3 years (24-38 years), were confronted with the test twice (1 week between sessions), during which salivary cortisol, heart rate (HR), high frequency heart rate variability (HF-HRV, parasympathetic activity), and T-wave amplitude (TWA, suggested to be related to sympathetic influence on myocardial performance) were assessed. Cortisol secretion showed a marked increase (88% vs. baseline) during the first stress provocation, but habituated in the second session. The magnitude of HR and TWA reactivity during stress provocation was approximately the same at both sessions, implying a stable increase in sympathetic activity. Heart rate showed a maximum increase of 40% at the first session, and 32% at the second. TWA showed a maximum decrease of 42% at the first session, and 39% at the second. The results resemble those obtained in prior studies using the real-life TSST. If these results can be replicated with larger samples, VR technology may be used as a simple and standardized tool for social stress induction in experimental settings.

Can architectural design alter the physiological reaction to psychosocial stress? A virtual TSST experiment

Is has long been established, that views to natural scenes can a have a dampening effect on physiological stress responses. However, as people in Europe, Canada and North America today spent 50-85% of their time indoors, attention might also be paid to how the artificial man-made indoor environment influences these mechanisms. The question that this study attempts to start addressing is therefore whether certain design, characteristics of indoor spaces can make a difference to the physiological stress response as well. Using a virtual version of the Trier Social Stress Test, in which the space is computer generated and properties of the space therefore can be systematically varied, we measured saliva cortisol and heart rate variability in participants in a closed room versus a room with openings. As shown by a significant linear contrast interaction between groups and TSST conditions, participants in the closed room responded with more pronounced cortisol reactivity to stress induction, and continued to show higher levels throughout recovery, compared to participants in the open room. No differences were found regarding any part of the autonomic nervous system.

A virtual reality version of the trier social stress test: A pilot study

One of the most common methods of inducing stress in the laboratory in order to examine the stress response in healthy and clinical populations is the Trier Social Stress Test (TSST). Briefly, the participant is asked to deliver a speech and to perform an arithmetic task in front of an evaluating committee. The committee, consisting of three trained actors, does not respond emotionally during the test, which makes the situation very stressful for the participant. One disadvantage of the TSST is that it can be difficult to hold the experimental conditions constant. In particular, it may be difficult for actors to hold their acting constant across all sessions. Furthermore, there are several practical problems and costs associated with hiring professional actors. A computerized version of the TSST using virtual humans could be a way to avoid these problems provided that it is able to induce a stress response similar to the one of the original TSST. The purpose of the present pilot study was therefore to investigate the stress response to a virtual reality (VR) version of the TSST visualized using an immersive VR system (VR-TSST). Seven healthy males with an average age of 24 years (range: 23–26 years) performed the VR-TSST. This included delivering a speech and performing an arithmetic task in front of an evaluating committee consisting of three virtual humans. The VR equipment was a CAVE equipped with stereoscopy and head tracking. ECG and respiration were recorded as well as the participants behavior and comments. Afterward, a semi-structured interview was carried out. In general, the subjective and physiological data from the experiment indicated that the VR version of the TSST induced a stress response in the seven participants. In particular, the peak increase in heart rate was close to rates observed in studies using the traditional TSST with real actors. These results suggest that virtual humans visualized with an immersive VR system can be used to induce stress under laboratory conditions.

WozARd: a wizard of oz method for wearable augmented reality interaction—a pilot study

Head-mounted displays and other wearable devices open up for innovative types of interaction for wearable augmented reality (AR). However, to design and evaluate these new types of AR user interfaces, it is essential to quickly simulate undeveloped components of the system and collect feedback from potential users early in the design process. One way of doing this is the wizard of Oz (WOZ) method. The basic idea behind WOZ is to create the illusion of a working system by having a human operator, performing some or all of the systems functions. WozARd is a WOZ method developed for wearable AR interaction. The presented pilot study was an initial investigation of the capability of the WozARd method to simulate an AR city tour. Qualitative and quantitative data were collected from 21 participants performing a simulated AR city tour. The data analysis focused on seven categories that can have an impact on how the WozARd method is perceived by participants: precision, relevance, responsiveness, technical stability, visual fidelity, general user-experience, and human-operator performance. Overall, the results indicate that the participants perceived the simulated AR city tour as a relatively realistic experience despite a certain degree of technical instability and human-operator mistakes.

Evaluating interactive computer-based scenarios designed for learning medical technology

The use of medical equipment is growing in healthcare, resulting in an increased need for resources to educate users in how to manage the various devices. Learning the practical operation of a device is one thing, but learning how to work with the device in the actual clinical context is more challenging. This paper presents a computer-based simulation prototype for learning medical technology in the context of critical care. Properties from simulation and computer games have been adopted to create a visualization-based, interactive and contextually bound tool for learning. A participatory design process, including three researchers and three practitioners from a clinic for infectious diseases, was adopted to adjust the form and content of the prototype to the needs of the clinical practice and to create a situated learning experience. An evaluation with 18 practitioners showed that practitioners were positive to this type of tool for learning and that it served as a good platform for eliciting and sharing knowledge. Our conclusion is that this type of tools can be a complement to traditional learning resources to situate the learning in a context without requiring advanced technology or being resource-demanding.

WozARd: a wizard of oz tool for mobile AR

Wizard of Oz methodology is useful when conducting user studies of a system that is in early development. It is essential to be able to simulate part of the system and to collect feedback from potential users. Using a human to act as the system is one way to do this. The Wizard of Oz tool presented here is called WozARd and it aims at offering a set of tools that help the test leader control the visual, tactile and auditive output that is presented to the test participant. Additionally, it is suitable for using in an augmented reality environment where images are overlaid on the phones camera view or on glasses. The main features that were identified as necessary include presentation of media such as images, video and sound, navigation and location based triggering, automatically taking photos, capability to log test results and visual feedback, and the integration of Sony SmartWatch for interaction possibilities.

Initial usability testing of navigation and interaction methods in virtual environments: developing usable interfaces for brain injury rehabilitation

It is speculated that virtual environments (VE) might be used as a training tool in brain injury rehabilitation. The rehabilitation process often involves practicing so-called instrumental activities of daily living (IADL), such as shopping, cooking, and using a telephone. If a brain injury patient is to practice such activities in a VE, the patient must be able to navigate the viewpoint and interact with virtual objects in an understandable way. People with brain injury may be less tolerant to a poor interface and a VE might therefore become unusable due to, for example, an unsuitable input device. In this paper we present two studies aimed to do initial usability testing of VE interaction methods on people without experience of 3D computer graphics. In the first study four navigation input device configurations were compared: the IntelliKeys keyboard and the Microsoft Sidewinder joystick, both programmed with two and three degrees of freedom (DOF). The purpose of the second study was to evaluate a method for interaction with objects, and to find a sufficiently usable input device for this purpose. The keyboard was found to be more suitable for navigation tasks in which the user wants to give the viewpoint a more advantageous position and orientation for carrying out a specific task. No big differences could be found between two and three DOFs. The method for interaction with objects was found to work sufficiently well. No difference in performance could be found between mouse and touch screen, but some evidence was found that they affect the usability of the VE interface in different ways.

Feasibility Study of Ubiquitous Interaction Concepts

There are all sorts of consumer electronics in a home environment. Using ”apps” to interact with each device is neither feasible nor practical in an ubicomp future. Prototyping and evaluating interaction concepts for this future is a challenge. This paper proposes four concepts for device discovery and device interaction implemented in a virtual environment. The interaction concepts were compared in a controlled experiment for evaluation and comparison. Some statistically significant dierences and subjective preferences could be observed in the quantitative and qualitative data respectively. Overall, the results indicate that the proposed interaction concepts were found natural and easy to use.

CellexalVR: A virtual reality platform for the exploration and analysis of single-cell gene expression data

Single-cell RNAseq is a routinely used technique to explore the composition of cell populations, and they are often visualised using dimension reduction methods where the cells are represented in two or three dimensional space. Many tools are available to do this but visualising and cross-comparing these representations can be challenging, especially when cells are projected onto three dimensions which can be more informative for complex datasets. Here we present CellexalVR (www.cellexalvr.med.lu.se), a feature-rich, fully interactive virtual reality environment for the visualisation and analysis of single-cell experiments that allows researchers to intuitively and collaboratively gain an understanding of their data.