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2024 |
Kim, Sanghee; Ryu, Jihye; Lee, Yujeong; Park, Hyejin; Lee, Kweonhyoung In: Buildings, vol. 14, no. 1, pp. 237, 2024. Abstract | Links | Tags: DSI-24, VR @article{kim2024methods,We propose a technique that allows designers to develop energy-efficient buildings focused on occupants from the early design stage. The technique integrates the physiological responses of occupants and the energy performance of buildings. Among the architectural design elements, we considered the aspect ratio, ceiling height, and window-to-wall ratio as design variables and created 30 design alternatives for a single-occupancy room in a postpartum care center. These design alternatives were recreated in virtual reality, allowing 33 female participants to immerse themselves in the designed rooms. During the experiment, we collected electroencephalography (EEG) data from the participants. Furthermore, we used DesignBuilder to simulate 30 design alternatives and calculated the primary energy consumption per unit area for each alternative. By integrating the EEG data and energy performance analysis, we identified the design alternative among the 30 options that positively influenced the physiological responses of occupants while also being energy efficient. The selected alternative was designed with an aspect ratio of 1:1.6, a ceiling height of 2.3 m, and a window-to-wall ratio of 60%. This research represents a creative exploration that demonstrates how studies combining human physiological responses and architecture can evolve through integration with other subjects. Our findings provide a robust framework to explore the relationship between physiological responses and energy optimization for detailed architectural design elements. |
2023 |
Chiossi, Francesco; Turgut, Yagiz; Welsch, Robin; Mayer, Sven Adapting Visual Complexity Based on Electrodermal Activity Improves Working Memory Performance in Virtual Reality Journal Article In: Proc. ACM Hum.-Comput. Interact, vol. 7, 2023. Abstract | Links | Tags: DSI-VR300, VR @article{chiossi2023adapting,Biocybernetic loops encompass users’ state detection and system adaptation based on physiological signals. Current adaptive systems limit the adaptation to task features such as task difficulty or multitasking demands. However, virtual reality allows the manipulation of task-irrelevant elements in the environment. We present a physiologically adaptive system that adjusts the virtual environment based on physiological arousal, i.e., electrodermal activity. We conducted a user study with our adaptive system in social virtual reality to verify improved performance. Here, participants completed an n back task, and we adapted the visual complexity of the environment by changing the number of non-player characters. Our results show that an adaptive virtual reality can control users’ comfort, performance, and workload by adapting the visual complexity based on physiological arousal. Thus, our physiologically adaptive system improves task performance and perceived workload. Finally, we embed our findings in physiological computing and discuss applications in various scenarios |
Chiossi, Francesco; Ou, Changkun; Mayer, Sven In: 2023. Abstract | Links | Tags: DSI-7, Multimodal, VR @article{chiossi2023exploring,Physiologically-adaptive Virtual Reality can drive interactions and adjust virtual content to better fit users’ needs and support specific goals. However, the complexity of psychophysiological inference hinders efficient adaptation as the relationship between cognitive and physiological features rarely show one-to-one correspondence. Therefore, it is necessary to employ multimodal approaches to evaluate the effect of adaptations. In this work, we analyzed a multimodal dataset (EEG, ECG, and EDA) acquired during interaction with a VR-adaptive system that employed EDA as input for adaptation of secondary task difficulty. We evaluated the effect of dynamic adjustments on different physiological features and their correlation. Our results show that when the adaptive system increased the secondary task difficulty, theta, beta, and phasic EDA features increased. Moreover, we found a high correlation between theta, alpha, and beta oscillations during difficulty adjustments. Our results show how specific EEG and EDA features can be employed for evaluating VR adaptive systems. |
2022 |
Chang, Won Kee; Lim, Hyunmi; Park, Seo Hyun; Lim, Chaiyoung; Paik, Nam-Jong; Kim, Won-Seok; Ku, Jeonghun Effect of Immersive Virtual Mirror Visual Feedback on Mu Suppression and Coherence in Motor and Parietal Cortex in Stroke Journal Article In: 2022. Abstract | Links | Tags: DSI-24, VR @article{chang2022effect,Background: This study aimed to investigate the activation pattern of the motor cortex (M1) and parietal cortex during immersive virtual reality (VR)-based mirror visual feedback (MVF) of the upper limb in patients with chronic stroke. Methods: Fourteen patients with chronic stroke with severe upper limb hemiparesis (Brunnstrom stage of hand 1-3) and 21 healthy controls were included. The participants performed wrist extension tasks with their unaffected wrists (or the dominant side in controls). In the MVF condition, the movement of the affected hand was synchronized with that of the unaffected hand. In contrast, only the movement of the unaffected hand was shown in the no-MVF condition. Electroencephalography was obtained during experiments with two conditions (MVF vs no-MVF). Mu suppression in the bilateral M1 and parietal cortex and mu coherence between the ipsilateral M1 and parietal cortex in each hemisphere and interhemispheric M1 were used for analyses. Results: In patients with stroke, MVF induced significant mu suppression in both the ipsilesional M1 and parietal lobes (p=0.006 and p=0.009, respectively), while significant mu suppression was observed in the bilateral M1 (p=0.003 for ipsilesional and p=0.041 for contralesional M1, respectively) and contralesional (contralateral hemisphere to the moving hand) parietal lobes in the healthy controls (p=0.036). The ipsilesional mu coherence between the M1 and parietal cortex in patients with stroke was stronger than that in controls regardless of MVF condition (p<0.001), while mu coherence between interhemispheric M1 cortices was significantly weaker in patients with stroke (p=0.032). Conclusion: In patients with stroke, MVF using immersive VR induces mu suppression in the ipsilesional M1 and parietal lobe. Our findings provide evidence of the neural mechanism of MVF using immersive VR and support its application in patients with stroke with severe hemiparesis. |
Miltiadous, Andreas; Aspiotis, Vasileios; Sakkas, Konstantinos; Giannakeas, Nikolaos; Glavas, Euripidis; Tzallas, Alexandros T An experimental protocol for exploration of stress in an immersive VR scenario with EEG Conference 2022 7th South-East Europe Design Automation, Computer Engineering, Computer Networks and Social Media Conference (SEEDA-CECNSM), IEEE 2022. Abstract | Links | Tags: DSI-24, VR @conference{miltiadous2022experimental,Stress is a subject always relevant to scientific research due to the numerous implications in human life. Typical biomarkers used in the physiological evaluation of stress include Electrocardiography, cortisol levels, galvanic skin response and other. Recently, one less widely used instrument for the assessment of stress that has been re-emerged due to advancements in computational power and machine learning techniques, is Electroencephalography. Moreover, as Virtual Reality HMDs are being rapidly adopted by the research community it becomes apparent that leveraging the offered advantages of VR for the exploration of stress can lead to novel controlable and reproducable experimental procedures. In this paper we combine EEG, ECG and the Perceived Stress Scale with a Virtual Reality phobia induction setting, to propose a protocol for assessing stress. The suggested protocol can be used for functional brain connectivity investigation and thus the evaluation of stress while it and can be expanded via the incorporation of machine learning algorithms for automatic stress level classification. |
Kim, Nayeon; Gero, John S Neurophysiological Responses to Biophilic Design: A Pilot Experiment Using VR and EEG Unpublished 2022. Abstract | Links | Tags: DSI-24, VR @unpublished{kimneurophysiological,This pilot study explores the effects of biophilic design on university students’ neurophysiological responses in virtual classrooms through measuring relative alpha and beta power using EEG in two different display conditions: a conventional computer display and an immersive VR HeadMounted Display. Seventeen male undergraduate students from both a design major and a non-design major in their twenties at Yonsei University participated. Seven different biophilic design cases were presented as visual stimuli to participants in the two different conditions. Results of ANOVA analysis revealed significant main effects of condition and hemisphere in the relative alpha power. Results revealed there is significant interaction effect between case and major as well as between condition, case, hemisphere, and major in relative beta power. Results showed statistically significant differences in some electrodes of both relative alpha and relative beta measurements between some cases when presented in the computer display. In the VR presentation, differences were found only in the relative beta in some electrodes. This study has the potential to contribute to building evidencebased design strategies for improving biophilic design environments. |
2021 |
Kim, Soram; Lee, Seungyun; Kang, Hyunsuk; Kim, Sion; Ahn, Minkyu P300 Brain--Computer Interface-Based Drone Control in Virtual and Augmented Reality Journal Article In: Sensors, vol. 21, no. 17, pp. 5765, 2021. Abstract | Links | Tags: BCI, DSI-VR300, VR @article{kim2021p300,Since the emergence of head-mounted displays (HMDs), researchers have attempted to introduce virtual and augmented reality (VR, AR) in brain–computer interface (BCI) studies. However, there is a lack of studies that incorporate both AR and VR to compare the performance in the two environments. Therefore, it is necessary to develop a BCI application that can be used in both VR and AR to allow BCI performance to be compared in the two environments. In this study, we developed an opensource-based drone control application using P300-based BCI, which can be used in both VR and AR. Twenty healthy subjects participated in the experiment with this application. They were asked to control the drone in two environments and filled out questionnaires before and after the experiment. We found no significant (p > 0.05) difference in online performance (classification accuracy and amplitude/latency of P300 component) and user experience (satisfaction about time length, program, environment, interest, difficulty, immersion, and feeling of self-control) between VR and AR. This indicates that the P300 BCI paradigm is relatively reliable and may work well in various situations |
Kim, Sanghee; Park, Hyejin; Choo, Seungyeon Effects of Changes to Architectural Elements on Human Relaxation-Arousal Responses: Based on VR and EEG Journal Article In: International Journal of Environmental Research and Public Health, vol. 18, no. 8, pp. 4305, 2021. Abstract | Links | Tags: DSI-24, VR @article{kim2021effects,This study combines electroencephalogram (EEG) with virtual reality (VR) technologies to measure the EEG responses of users experiencing changes to architectural elements. We analyze the ratio of alpha to beta waves (RAB) indicators to determine the pre- and poststimulation changes. In our methodology, thirty-three females experience using private rooms in a postpartum care center participated in the experiment. Their brain waves are measured while they are experiencing the VR space of a private room in a postpartum care center. Three architectural elements (i.e., aspect ratio of space, ceiling height, and window ratio) are varied in the VR space. In addition, a self-report questionnaire is administered to examine whether the responses are consistent with the results of the EEG response analysis. As a result, statistically significant differences (p < 0.05) are observed in the changes in the RAB indicator values of the pre- and poststimulation EEG while the subjects are experiencing the VR space where the architectural elements are varied. That is, the effects of the changes to architectural elements on users’ relaxation-arousal responses are statistically verified. Notably, in all the RAB indicator values where significant differences are observed, the poststimulation RAB decreases in comparison to the prestimulus ratios, which is indicative of the arousal response. However, the arousal levels vary across the architectural elements, which implies it would be possible to find out the elements that could induce less arousal response using the proposed method. Moreover, following the experience in the VR space, certain lobes of the brain (F4 and P3 EEG channels) show statistically significant differences in the relaxation-arousal responses. Unlike previous studies, which measured users’ physiological responses to abstract and primordial spatial elements, this study extends the boundaries of the literature by applying the architectural elements applicable to design in practice |
2020 |
Kim, Young-June; Park, Jin-Hong; Cho, Young-Suk; Kim, Keum-Sook In: Journal of Convergence for Information Technology, vol. 10, no. 8, pp. 203–212, 2020. Abstract | Links | Tags: DSI-24, VR @article{kim2020effect,The purpose of this study was to investigate the effects of cognitive rehabilitation programs using Virtual Reality(VR) content on the daily living abilities such as cognitive abilities, depression, and upper extremity functions of the elderly. The study group analyzed the effectiveness by separating the experimental group, which is the virtual reality cognitive rehabilitation application group, and the control group, the universal cognitive stimulation program application group. As a result of the study, the MMSE-K score improved by 13.0% in the experimental group and 2.3% in the control group. The improvement in each area of the experimental group was found to be 3.1% MBI, 7.1% MFT(Rt.), 3.5% MFT(Lt.), and 25.4% K-GDS. As a result of comparing the pre-post score change between each group, there was a significant difference between groups in daily living ability (p<.001) and MFT(Rt.)(p<.01). In addition, as a result of comparing the changes in absolute alpha waves to confirm the degree of depression through brain waves, there was no statistically significant difference. However, in the experimental group, it was confirmed that the average value increased to a positive value. This study is an experiment to verify the effectiveness of the cognitive rehabilitation program using virtual reality contents, and suggests a new intervention method to maintain and improve the daily life ability, cognitive function, depression and upper extremity function of the elderly. |
Lim, Hyunmi; Kim, Won-Seok; Ku, Jeonghun Transcranial Direct Current Stimulation Effect on Virtual Hand Illusion Journal Article In: Cyberpsychology, Behavior, and Social Networking, vol. 23, no. 8, pp. 541–549, 2020. Abstract | Links | Tags: DSI-24, Neuromodulation, Stroke, VR @article{lim2020transcranial,Virtual reality (VR) is effectively used to evoke the mirror illusion, and transcranial direct current stimulation (tDCS) synergistically facilitates this illusion. This study investigated whether a mirror virtual hand illusion (MVHI) induced by an immersive, first-person-perspective, virtual mirror system could be modulated by tDCS of the primary motor cortex. Fourteen healthy adults (average age 21.86 years ±0.47, seven men and seven women) participated in this study, and they experienced VR with and without tDCS—the tDCS and sham conditions, each of which takes ∼30 minutes—on separate days to allow the washout of the tDCS effect. While experiencing VR, the movements of the virtual left hand reflected the flexion and extension of the real right hand. Subsequently, electroencephalogram was recorded, the magnitude of the proprioceptive shift was measured, and the participants provided responses to a questionnaire regarding hand ownership. A significant difference in the proprioceptive shift was observed between the tDCS and sham conditions. In addition, there was significant suppression of the mu power in Pz, and augmentation of the beta power in the Pz, P4, O1, and O2 channels. The difference in proprioceptive deviation between the two conditions showed significant negative correlation with mu suppression over the left frontal lobe in the tDCS condition. Finally, the question “I felt that the virtual hand was my own hand” received a significantly higher score under the tDCS condition. In short, applying tDCS over the motor cortex facilitates the MVHI by activating the attentional network over the parietal and frontal lobes such that the MVHI induces more proprioceptive drift, which suggests that the combination of VR and tDCS can enhance the immersive effect in VR. This result provides better support for the use of the MVHI paradigm in combination with tDCS for recovery from illnesses such as stroke. |
2019 |
Goethem, Sander Van; Adema, Kimberly; van Bergen, Britt; Viaene, Emilia; Wenborn, Eva; Verwulgen, Stijn A Test Setting to Compare Spatial Awareness on Paper and in Virtual Reality Using EEG Signals Conference International Conference on Applied Human Factors and Ergonomics, Springer 2019. Abstract | Links | Tags: BCI, Cognitive-Algorithm, DSI-7, VR @conference{van2019test,Spatial awareness and the ability to analyze spatial objects, manipulate them and assess the effect thereof, is a key competence for industrial designers. Skills are gradually built up throughout most educational design programs, starting with exercises on technical drawings and reconstruction or classification of spatial objects from isometric projections and CAD practice. The accuracy in which spatial assignments are conducted and the amount of effort required to fulfill them, highly depend on individual insight, interests and persistence. Thus each individual has its own struggles and learning curve to master the structure of spatial objects in aesthetic and functional design. Virtual reality (VR) is a promising tool to expose subjects to objects with complex spatial structure, and even manipulate and design spatial characteristics of such objects. The advantage of displaying spatial objects in VR, compared to representations by projecting them on a screen or paper, could be that subjects could more accurately assess spatial properties of and object and its full geometrical and/or mechanical complexity, when exposed to that object in VR. Immersive experience of spatial objects, could not only result in faster acquiring spatial insights, but also potentially with less effort. We propose that acquiring spatial insight in VR could leverage individual differences in skills and talents and that under this proposition VR can be used as a promising tool in design education. A first step in underpinning this hypothesis, is acquisition of cognitive workload that can be used and compared both in VR and in a classical teaching context. We use electroencephalography (EEG) to assess brain activity through wearable plug and play headset (Wearable Sensing-DSI 7). This equipment is combined with VR (Oculus). We use QStates classification software to compare brain waves when conducting spatial assessments on paper and in VR. This gives us a measure of cognitive workload, as a ratio of a resulting from subject records with a presumed ‘high’ workload. A total number of eight records of subjects were suited for comparison. No significant difference was found between EEG signals (paried t-test, p = 0.57). However the assessment of cognitive workload was successfully validated through a questionnaire. The method could be used to set up reliable constructs for learning techniques for spatial insights. |
2018 |
Vergeer, Mark; Mesik, Juraj; Baek, Yihwa; Wilmerding, Kelton; Engel, Stephen A Orientation-selective contrast adaptation measured with SSVEP Journal Article In: Journal of Vision, vol. 18, no. 5, pp. 2–2, 2018. Abstract | Links | Tags: DSI-7, VR @article{vergeer2018orientation,Exposure to oriented luminance contrast patterns causes a reduction in visual sensitivity specifically for the adapter orientation. This orientation selectivity is probably the most studied aspect of contrast adaptation, but it has rarely been measured with steady-state visually evoked potentials (SSVEPs), despite their becoming one of the more popular methods of human neuroscience. Here, we measured orientation selective adaptation by presenting a plaid stimulus of which the horizontal and vertical grating reversed contrast at different temporal frequencies, while recording EEG signals from occipital visual areas. In three experiments, we compared SSVEP responses to the plaid before and after adaptation. All experiments showed a significant decrease in SSVEP response at the frequency of the adapter orientation, whereas such an effect was absent for the frequency of the orthogonal orientation. Adaptation also led to robust phase delays, selectively for the SSVEP frequency corresponding to the adapter orientation. These results demonstrate the efficiency of SSVEPs for measuring orientation selective adaptation; the method can measure changes in both amplitude and phase, simultaneously for two orientations. |
2024 |
Kim, Sanghee; Ryu, Jihye; Lee, Yujeong; Park, Hyejin; Lee, Kweonhyoung In: Buildings, vol. 14, no. 1, pp. 237, 2024. @article{kim2024methods,We propose a technique that allows designers to develop energy-efficient buildings focused on occupants from the early design stage. The technique integrates the physiological responses of occupants and the energy performance of buildings. Among the architectural design elements, we considered the aspect ratio, ceiling height, and window-to-wall ratio as design variables and created 30 design alternatives for a single-occupancy room in a postpartum care center. These design alternatives were recreated in virtual reality, allowing 33 female participants to immerse themselves in the designed rooms. During the experiment, we collected electroencephalography (EEG) data from the participants. Furthermore, we used DesignBuilder to simulate 30 design alternatives and calculated the primary energy consumption per unit area for each alternative. By integrating the EEG data and energy performance analysis, we identified the design alternative among the 30 options that positively influenced the physiological responses of occupants while also being energy efficient. The selected alternative was designed with an aspect ratio of 1:1.6, a ceiling height of 2.3 m, and a window-to-wall ratio of 60%. This research represents a creative exploration that demonstrates how studies combining human physiological responses and architecture can evolve through integration with other subjects. Our findings provide a robust framework to explore the relationship between physiological responses and energy optimization for detailed architectural design elements. |
2023 |
Chiossi, Francesco; Turgut, Yagiz; Welsch, Robin; Mayer, Sven Adapting Visual Complexity Based on Electrodermal Activity Improves Working Memory Performance in Virtual Reality Journal Article In: Proc. ACM Hum.-Comput. Interact, vol. 7, 2023. @article{chiossi2023adapting,Biocybernetic loops encompass users’ state detection and system adaptation based on physiological signals. Current adaptive systems limit the adaptation to task features such as task difficulty or multitasking demands. However, virtual reality allows the manipulation of task-irrelevant elements in the environment. We present a physiologically adaptive system that adjusts the virtual environment based on physiological arousal, i.e., electrodermal activity. We conducted a user study with our adaptive system in social virtual reality to verify improved performance. Here, participants completed an n back task, and we adapted the visual complexity of the environment by changing the number of non-player characters. Our results show that an adaptive virtual reality can control users’ comfort, performance, and workload by adapting the visual complexity based on physiological arousal. Thus, our physiologically adaptive system improves task performance and perceived workload. Finally, we embed our findings in physiological computing and discuss applications in various scenarios |
Chiossi, Francesco; Ou, Changkun; Mayer, Sven In: 2023. @article{chiossi2023exploring,Physiologically-adaptive Virtual Reality can drive interactions and adjust virtual content to better fit users’ needs and support specific goals. However, the complexity of psychophysiological inference hinders efficient adaptation as the relationship between cognitive and physiological features rarely show one-to-one correspondence. Therefore, it is necessary to employ multimodal approaches to evaluate the effect of adaptations. In this work, we analyzed a multimodal dataset (EEG, ECG, and EDA) acquired during interaction with a VR-adaptive system that employed EDA as input for adaptation of secondary task difficulty. We evaluated the effect of dynamic adjustments on different physiological features and their correlation. Our results show that when the adaptive system increased the secondary task difficulty, theta, beta, and phasic EDA features increased. Moreover, we found a high correlation between theta, alpha, and beta oscillations during difficulty adjustments. Our results show how specific EEG and EDA features can be employed for evaluating VR adaptive systems. |
2022 |
Chang, Won Kee; Lim, Hyunmi; Park, Seo Hyun; Lim, Chaiyoung; Paik, Nam-Jong; Kim, Won-Seok; Ku, Jeonghun Effect of Immersive Virtual Mirror Visual Feedback on Mu Suppression and Coherence in Motor and Parietal Cortex in Stroke Journal Article In: 2022. @article{chang2022effect,Background: This study aimed to investigate the activation pattern of the motor cortex (M1) and parietal cortex during immersive virtual reality (VR)-based mirror visual feedback (MVF) of the upper limb in patients with chronic stroke. Methods: Fourteen patients with chronic stroke with severe upper limb hemiparesis (Brunnstrom stage of hand 1-3) and 21 healthy controls were included. The participants performed wrist extension tasks with their unaffected wrists (or the dominant side in controls). In the MVF condition, the movement of the affected hand was synchronized with that of the unaffected hand. In contrast, only the movement of the unaffected hand was shown in the no-MVF condition. Electroencephalography was obtained during experiments with two conditions (MVF vs no-MVF). Mu suppression in the bilateral M1 and parietal cortex and mu coherence between the ipsilateral M1 and parietal cortex in each hemisphere and interhemispheric M1 were used for analyses. Results: In patients with stroke, MVF induced significant mu suppression in both the ipsilesional M1 and parietal lobes (p=0.006 and p=0.009, respectively), while significant mu suppression was observed in the bilateral M1 (p=0.003 for ipsilesional and p=0.041 for contralesional M1, respectively) and contralesional (contralateral hemisphere to the moving hand) parietal lobes in the healthy controls (p=0.036). The ipsilesional mu coherence between the M1 and parietal cortex in patients with stroke was stronger than that in controls regardless of MVF condition (p<0.001), while mu coherence between interhemispheric M1 cortices was significantly weaker in patients with stroke (p=0.032). Conclusion: In patients with stroke, MVF using immersive VR induces mu suppression in the ipsilesional M1 and parietal lobe. Our findings provide evidence of the neural mechanism of MVF using immersive VR and support its application in patients with stroke with severe hemiparesis. |
Miltiadous, Andreas; Aspiotis, Vasileios; Sakkas, Konstantinos; Giannakeas, Nikolaos; Glavas, Euripidis; Tzallas, Alexandros T An experimental protocol for exploration of stress in an immersive VR scenario with EEG Conference 2022 7th South-East Europe Design Automation, Computer Engineering, Computer Networks and Social Media Conference (SEEDA-CECNSM), IEEE 2022. @conference{miltiadous2022experimental,Stress is a subject always relevant to scientific research due to the numerous implications in human life. Typical biomarkers used in the physiological evaluation of stress include Electrocardiography, cortisol levels, galvanic skin response and other. Recently, one less widely used instrument for the assessment of stress that has been re-emerged due to advancements in computational power and machine learning techniques, is Electroencephalography. Moreover, as Virtual Reality HMDs are being rapidly adopted by the research community it becomes apparent that leveraging the offered advantages of VR for the exploration of stress can lead to novel controlable and reproducable experimental procedures. In this paper we combine EEG, ECG and the Perceived Stress Scale with a Virtual Reality phobia induction setting, to propose a protocol for assessing stress. The suggested protocol can be used for functional brain connectivity investigation and thus the evaluation of stress while it and can be expanded via the incorporation of machine learning algorithms for automatic stress level classification. |
Kim, Nayeon; Gero, John S Neurophysiological Responses to Biophilic Design: A Pilot Experiment Using VR and EEG Unpublished 2022. @unpublished{kimneurophysiological,This pilot study explores the effects of biophilic design on university students’ neurophysiological responses in virtual classrooms through measuring relative alpha and beta power using EEG in two different display conditions: a conventional computer display and an immersive VR HeadMounted Display. Seventeen male undergraduate students from both a design major and a non-design major in their twenties at Yonsei University participated. Seven different biophilic design cases were presented as visual stimuli to participants in the two different conditions. Results of ANOVA analysis revealed significant main effects of condition and hemisphere in the relative alpha power. Results revealed there is significant interaction effect between case and major as well as between condition, case, hemisphere, and major in relative beta power. Results showed statistically significant differences in some electrodes of both relative alpha and relative beta measurements between some cases when presented in the computer display. In the VR presentation, differences were found only in the relative beta in some electrodes. This study has the potential to contribute to building evidencebased design strategies for improving biophilic design environments. |
2021 |
Kim, Soram; Lee, Seungyun; Kang, Hyunsuk; Kim, Sion; Ahn, Minkyu P300 Brain--Computer Interface-Based Drone Control in Virtual and Augmented Reality Journal Article In: Sensors, vol. 21, no. 17, pp. 5765, 2021. @article{kim2021p300,Since the emergence of head-mounted displays (HMDs), researchers have attempted to introduce virtual and augmented reality (VR, AR) in brain–computer interface (BCI) studies. However, there is a lack of studies that incorporate both AR and VR to compare the performance in the two environments. Therefore, it is necessary to develop a BCI application that can be used in both VR and AR to allow BCI performance to be compared in the two environments. In this study, we developed an opensource-based drone control application using P300-based BCI, which can be used in both VR and AR. Twenty healthy subjects participated in the experiment with this application. They were asked to control the drone in two environments and filled out questionnaires before and after the experiment. We found no significant (p > 0.05) difference in online performance (classification accuracy and amplitude/latency of P300 component) and user experience (satisfaction about time length, program, environment, interest, difficulty, immersion, and feeling of self-control) between VR and AR. This indicates that the P300 BCI paradigm is relatively reliable and may work well in various situations |
Kim, Sanghee; Park, Hyejin; Choo, Seungyeon Effects of Changes to Architectural Elements on Human Relaxation-Arousal Responses: Based on VR and EEG Journal Article In: International Journal of Environmental Research and Public Health, vol. 18, no. 8, pp. 4305, 2021. @article{kim2021effects,This study combines electroencephalogram (EEG) with virtual reality (VR) technologies to measure the EEG responses of users experiencing changes to architectural elements. We analyze the ratio of alpha to beta waves (RAB) indicators to determine the pre- and poststimulation changes. In our methodology, thirty-three females experience using private rooms in a postpartum care center participated in the experiment. Their brain waves are measured while they are experiencing the VR space of a private room in a postpartum care center. Three architectural elements (i.e., aspect ratio of space, ceiling height, and window ratio) are varied in the VR space. In addition, a self-report questionnaire is administered to examine whether the responses are consistent with the results of the EEG response analysis. As a result, statistically significant differences (p < 0.05) are observed in the changes in the RAB indicator values of the pre- and poststimulation EEG while the subjects are experiencing the VR space where the architectural elements are varied. That is, the effects of the changes to architectural elements on users’ relaxation-arousal responses are statistically verified. Notably, in all the RAB indicator values where significant differences are observed, the poststimulation RAB decreases in comparison to the prestimulus ratios, which is indicative of the arousal response. However, the arousal levels vary across the architectural elements, which implies it would be possible to find out the elements that could induce less arousal response using the proposed method. Moreover, following the experience in the VR space, certain lobes of the brain (F4 and P3 EEG channels) show statistically significant differences in the relaxation-arousal responses. Unlike previous studies, which measured users’ physiological responses to abstract and primordial spatial elements, this study extends the boundaries of the literature by applying the architectural elements applicable to design in practice |
2020 |
Kim, Young-June; Park, Jin-Hong; Cho, Young-Suk; Kim, Keum-Sook In: Journal of Convergence for Information Technology, vol. 10, no. 8, pp. 203–212, 2020. @article{kim2020effect,The purpose of this study was to investigate the effects of cognitive rehabilitation programs using Virtual Reality(VR) content on the daily living abilities such as cognitive abilities, depression, and upper extremity functions of the elderly. The study group analyzed the effectiveness by separating the experimental group, which is the virtual reality cognitive rehabilitation application group, and the control group, the universal cognitive stimulation program application group. As a result of the study, the MMSE-K score improved by 13.0% in the experimental group and 2.3% in the control group. The improvement in each area of the experimental group was found to be 3.1% MBI, 7.1% MFT(Rt.), 3.5% MFT(Lt.), and 25.4% K-GDS. As a result of comparing the pre-post score change between each group, there was a significant difference between groups in daily living ability (p<.001) and MFT(Rt.)(p<.01). In addition, as a result of comparing the changes in absolute alpha waves to confirm the degree of depression through brain waves, there was no statistically significant difference. However, in the experimental group, it was confirmed that the average value increased to a positive value. This study is an experiment to verify the effectiveness of the cognitive rehabilitation program using virtual reality contents, and suggests a new intervention method to maintain and improve the daily life ability, cognitive function, depression and upper extremity function of the elderly. |
Lim, Hyunmi; Kim, Won-Seok; Ku, Jeonghun Transcranial Direct Current Stimulation Effect on Virtual Hand Illusion Journal Article In: Cyberpsychology, Behavior, and Social Networking, vol. 23, no. 8, pp. 541–549, 2020. @article{lim2020transcranial,Virtual reality (VR) is effectively used to evoke the mirror illusion, and transcranial direct current stimulation (tDCS) synergistically facilitates this illusion. This study investigated whether a mirror virtual hand illusion (MVHI) induced by an immersive, first-person-perspective, virtual mirror system could be modulated by tDCS of the primary motor cortex. Fourteen healthy adults (average age 21.86 years ±0.47, seven men and seven women) participated in this study, and they experienced VR with and without tDCS—the tDCS and sham conditions, each of which takes ∼30 minutes—on separate days to allow the washout of the tDCS effect. While experiencing VR, the movements of the virtual left hand reflected the flexion and extension of the real right hand. Subsequently, electroencephalogram was recorded, the magnitude of the proprioceptive shift was measured, and the participants provided responses to a questionnaire regarding hand ownership. A significant difference in the proprioceptive shift was observed between the tDCS and sham conditions. In addition, there was significant suppression of the mu power in Pz, and augmentation of the beta power in the Pz, P4, O1, and O2 channels. The difference in proprioceptive deviation between the two conditions showed significant negative correlation with mu suppression over the left frontal lobe in the tDCS condition. Finally, the question “I felt that the virtual hand was my own hand” received a significantly higher score under the tDCS condition. In short, applying tDCS over the motor cortex facilitates the MVHI by activating the attentional network over the parietal and frontal lobes such that the MVHI induces more proprioceptive drift, which suggests that the combination of VR and tDCS can enhance the immersive effect in VR. This result provides better support for the use of the MVHI paradigm in combination with tDCS for recovery from illnesses such as stroke. |
2019 |
Goethem, Sander Van; Adema, Kimberly; van Bergen, Britt; Viaene, Emilia; Wenborn, Eva; Verwulgen, Stijn A Test Setting to Compare Spatial Awareness on Paper and in Virtual Reality Using EEG Signals Conference International Conference on Applied Human Factors and Ergonomics, Springer 2019. @conference{van2019test,Spatial awareness and the ability to analyze spatial objects, manipulate them and assess the effect thereof, is a key competence for industrial designers. Skills are gradually built up throughout most educational design programs, starting with exercises on technical drawings and reconstruction or classification of spatial objects from isometric projections and CAD practice. The accuracy in which spatial assignments are conducted and the amount of effort required to fulfill them, highly depend on individual insight, interests and persistence. Thus each individual has its own struggles and learning curve to master the structure of spatial objects in aesthetic and functional design. Virtual reality (VR) is a promising tool to expose subjects to objects with complex spatial structure, and even manipulate and design spatial characteristics of such objects. The advantage of displaying spatial objects in VR, compared to representations by projecting them on a screen or paper, could be that subjects could more accurately assess spatial properties of and object and its full geometrical and/or mechanical complexity, when exposed to that object in VR. Immersive experience of spatial objects, could not only result in faster acquiring spatial insights, but also potentially with less effort. We propose that acquiring spatial insight in VR could leverage individual differences in skills and talents and that under this proposition VR can be used as a promising tool in design education. A first step in underpinning this hypothesis, is acquisition of cognitive workload that can be used and compared both in VR and in a classical teaching context. We use electroencephalography (EEG) to assess brain activity through wearable plug and play headset (Wearable Sensing-DSI 7). This equipment is combined with VR (Oculus). We use QStates classification software to compare brain waves when conducting spatial assessments on paper and in VR. This gives us a measure of cognitive workload, as a ratio of a resulting from subject records with a presumed ‘high’ workload. A total number of eight records of subjects were suited for comparison. No significant difference was found between EEG signals (paried t-test, p = 0.57). However the assessment of cognitive workload was successfully validated through a questionnaire. The method could be used to set up reliable constructs for learning techniques for spatial insights. |
2018 |
Vergeer, Mark; Mesik, Juraj; Baek, Yihwa; Wilmerding, Kelton; Engel, Stephen A Orientation-selective contrast adaptation measured with SSVEP Journal Article In: Journal of Vision, vol. 18, no. 5, pp. 2–2, 2018. @article{vergeer2018orientation,Exposure to oriented luminance contrast patterns causes a reduction in visual sensitivity specifically for the adapter orientation. This orientation selectivity is probably the most studied aspect of contrast adaptation, but it has rarely been measured with steady-state visually evoked potentials (SSVEPs), despite their becoming one of the more popular methods of human neuroscience. Here, we measured orientation selective adaptation by presenting a plaid stimulus of which the horizontal and vertical grating reversed contrast at different temporal frequencies, while recording EEG signals from occipital visual areas. In three experiments, we compared SSVEP responses to the plaid before and after adaptation. All experiments showed a significant decrease in SSVEP response at the frequency of the adapter orientation, whereas such an effect was absent for the frequency of the orthogonal orientation. Adaptation also led to robust phase delays, selectively for the SSVEP frequency corresponding to the adapter orientation. These results demonstrate the efficiency of SSVEPs for measuring orientation selective adaptation; the method can measure changes in both amplitude and phase, simultaneously for two orientations. |
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