• Journal of the Korean Society of Physical Medicine
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• v.16 no.4
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• pp.125-137
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• 2021

PURPOSE: The growing number of people exposed to a static sitting posture has resulted in an increase in people with a poor posture out of the optimally aligned posture because of the low awareness of a correct sitting posture. Learning the correct sitting posture by applying sensory feedback is essential because a poor posture has negative consequences for the spine. Therefore, this study examined the effects of the sensory feedback types on learning correct sitting posture. METHODS: Thirty-six healthy adult males were assigned to a visual feedback group, a tactile feedback group, and a visuotactile feedback group to learn the correct sitting posture by applying sensory feedback. The spine angle, muscle activity, and muscle thickness were measured in the sitting position using retro-reflexive markers, electromyography, and ultrasound immediately after, five minutes, and 10 minutes after intervention. RESULTS: The intervention time was significantly shorter in the visuotactile feedback group than the visual feedback group (p < .05). Compared to the pre-intervention, the repositioning error angles of the thoracic and lumbar vertebrae of all groups were reduced significantly immediately after intervention and after five minutes. After 10 minutes, there was a significant difference in the thoracic and lumbar repositioning error angles of the tactile feedback group and the visuotactile feedback group (p < .05). No significant difference was noted at any time compared to the pre-intervention in all groups (p > .05). CONCLUSION: The use of tactile and visuotactile feedback in intervention to correct the sitting posture is proposed.

• Journal of the Korea Computer Graphics Society
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• v.28 no.3
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• pp.1-11
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• 2022

Body ownership illusion (BOI), which means 'the illusion that a non-bodily object feels like my body', has been actively studied since the Rubber-hand Illusion showed that a person can feel a rubber hand like one's own hand. It has been proven that BOI can be elicited for virtual bodies in virtual reality. Although many studies have been examined the effect of visuomotor (VM) and visuotactile (VT) stimuli, which are mainly used for the elicitation of BOI, there were very limited studies that delivered both stimuli to the whole body at the same time. In this paper, we investigated how each stimulus affects BOI when delivering VM and VT stimulisimultaneously to the virtual avatar, and examined user experience that appears as presence, emotion, and virtual motion sickness. The results showed that BOI was high when VM is synchronous, but there was no significant difference according to VT levels. In the case of presence, it was confirmed that VT affects only when VM is synchronous, and in the case of emotion, both VM and VT affect valence, and in the case of virtual motion sickness, a statistical difference is not found.These results suggest that overall synchrony of VM is important factor in BOI with virtual avatars, but that the matching VT affects subjective experience such as presence when VM is synchronous.

• The Journal of Korean Academy of Sensory Integration
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• v.8 no.1
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• pp.41-49
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• 2010

Objective : Multisensory integration (MSI) is the essential process to use diverse sensory information for cognitive task or execution of motor action. Especially, visual and somatosensory integration is critical for motor behavior and coordination. This study was designed to explain spatial and temporal characteristics of visual and somatosensory integration by neurophysiological research method that identifies the time course and brain location of the SI process. Methods : Electroencephalography (EEG) and event-related potential (ERP) is used in this study in order to observe neural activities when integrating visual and tactile input. We calculate the linear summation (SUM) of visual-related potentials (VEPs) and somatosensory-related potentials (SEPs), and compared the SUM with simultaneously presented visual-tactile ERPs(SIM) Results : There were significant differences between the SIM and SUM in later time epochs (about 200-300ms) at contralateral somatosensory areas (C4) and occipital cortices (O1&O2). The amplitude of the SIM was mathematically larger than the summed signals, implying that the integration made some extra neural activities. Conclusion : This study provides some empirical neural evidence of that multisensory integration is more powerful than just combing two unisensory inputs in the brain and ERP data reveals neural signature relating to multisensory integrative process. Since this study is preliminary pilot study, larger population and criteria are needed for level of the significance. Further study is recommended to consider issues including effect of internally-driven attention and laterality of interaction to make the evidence by this study solid.