Sangwoo Cho

Nuclear factor-kappa B activation pathway in intestinal epithelial cells is a major regulator of chemokine gene expression and neutrophil migration induced by Bacteroides fragilis enterotoxin

Although intestinal epithelial cells are known to up‐regulate the expression of several chemokine genes in response to the stimulation with B. fragilis enterotoxin (BFT), there has been little understanding on the cellular mechanisms of BFT‐induced mucosal inflammation. To test whether nuclear transcriptional factor‐kappa B (NF‐κB) is involved in the process, we stimulated intestinal epithelial cells with BFT, and evaluated the signalling NF‐κB pathways. BFT increased signals of NF‐κB in HT‐29 and T84 epithelial cell lines as well as primary human colon epithelial cells. NF‐κB molecules activated by BFT stimulation were composed of p65 and p50 heterodimers. In contrast, BFT decreased the signals of IκBα and IκBɛ, as assessed by immunoblot. Super‐repressors of IκBα, IκB kinase (IKK)β, and NF‐κB inducing kinase (NIK) inhibited an up‐regulated transcription of downstream target gene (CXCL8) of NF‐κB. Moreover, blocking the activation of NF‐κB by MG‐132 or antisense p50 oligonucleotide transfection resulted in down‐regulated expression of chemokines such as CXCL1, CXCL8, and CCL2 in BFT‐stimulated HT‐29 cells. In addition, NF‐κB inhibition suppressed the BFT‐induced neutrophil transepithelial migration in T84 cells. These results indicate that NF‐κB can be a central regulator of chemokine gene expression in BFT‐stimulated intestinal epithelial cells and may be an important regulator of neutrophil migration.

Development of virtual reality proprioceptive rehabilitation system for stroke patients

In this study, the virtual reality (VR) proprioception rehabilitation system was developed for stroke patients to use proprioception feedback in upper limb rehabilitation by blocking visual feedback. To evaluate its therapeutic effect, 10 stroke patients (onset>3 month) trained proprioception feedback rehabilitation for one week and visual feedback rehabilitation for another week in random order. Proprioception functions were checked before, a week after, and at the end of training. The results show the click count, error distance and total error distance among proprioception evaluation factors were significantly reduced after proprioception feedback training compared to visual feedback training (respectively, p=0.005, p=0.001, and p=0.007). In addition, subjects were significantly improved in conventional behavioral tests after training. In conclusion, we showed the effectiveness and possible use of the VR to recover the proprioception of stroke patients.

Upper extremity rehabilitation of stroke: Facilitation of corticospinal excitability using virtual mirror paradigm

BackgroundSeveral experimental studies in stroke patients suggest that mirror therapy and various virtual reality programs facilitate motor rehabilitation. However, the underlying mechanisms for these therapeutic effects have not been previously described.ObjectivesWe attempted to delineate the changes in corticospinal excitability when individuals were asked to exercise their upper extremity using a real mirror and virtual mirror. Moreover, we attempted to delineate the role of visual modulation within the virtual environment that affected corticospinal excitability in healthy subjects and stroke patients.MethodsA total of 18 healthy subjects and 18 hemiplegic patients were enrolled into the study. Motor evoked potential (MEP)s from transcranial magnetic stimulation were recorded in the flexor carpi radialis of the non-dominant or affected upper extremity using three different conditions: (A) relaxation; (B) real mirror; and (C) virtual mirror. Moreover, we compared the MEPs from the virtual mirror paradigm using continuous visual feedback or intermittent visual feedback.ResultsThe rates of amplitude increment and latency decrement of MEPs in both groups were higher during the virtual mirror task than during the real mirror. In healthy subjects and stroke patients, the virtual mirror task with intermittent visual feedback significantly facilitated corticospinal excitability of MEPs compared with continuous visual feedback.ConclusionCorticospinal excitability was facilitated to a greater extent in the virtual mirror paradigm than in the real mirror and in intermittent visual feedback than in the continuous visual feedback, in both groups. This provides neurophysiological evidence supporting the application of the virtual mirror paradigm using various visual modulation technologies to upper extremity rehabilitation in stroke patients.

Development and Verification of an Alcohol Craving–Induction Tool Using Virtual Reality: Craving Characteristics in Social Pressure Situation

Alcoholism is a disease that affects parts of the brain that control emotion, decisions, and behavior. Therapy for people with alcoholism must address coping skills for facing high-risk situations. Therefore, it is important to develop tools to mimic such conditions. Cue exposure therapy (CET) provides high-risk situations during treatment, which raises the individuals ability to recognize that alcohol craving is being induced. Using CET, it is hard to simulate situations that induce alcohol craving. By contrast, virtual reality (VR) approaches can present realistic situations that cannot be experienced directly in CET. Therefore, we hypothesized that is possible to model social pressure situations using VR. We developed a VR system for inducing alcohol craving under social pressure situations and measured both the induced alcohol craving and head gaze of participants. A 2 x 2 experimental model (alcohol-related locality vs. social pressure) was designed. In situations without an avatar (no social pressure), more alcohol craving was induced if alcohol was present than if it was not. And more alcohol craving was induced in situations with an avatar (social pressure) than in situations without an avatar (no social pressure). The difference of angle between the direction of head gazing and the direction of alcohol or avatar was smaller in situations with an avatar alone (social pressure) than in situations with alcohol alone. In situations with both alcohol and an avatar, the angle between the direction of head gaze and the direction of the avatar was smaller than between the direction of head gaze and the direction of the alcohol. Considering the results, this VR system induces alcohol craving using an avatar that can express various social pressure situations.

Social pressure-induced craving in patients with alcohol dependence: application of virtual reality to coping skill training.

Objective This study was conducted to assess the interaction between alcohol cues and social pressure in the induction of alcohol craving. Methods Fourteen male patients with alcohol dependence and 14 age-matched social drinkers completed a virtual reality coping skill training program composed of four blocks according to the presence of alcohol cues (×2) and social pressure (×2). Before and after each block, the craving levels were measured using a visual analogue scale. Results Patients with alcohol dependence reported extremely high levels of craving immediately upon exposure to a virtual environment with alcohol cues, regardless of social pressure. In contrast, the craving levels of social drinkers were influenced by social pressure from virtual avatars. Conclusion Our findings imply that an alcohol cue-laden environment should interfere with the ability to use coping skills against social pressure in real-life situations.

Utility of a Three-Dimensional Interactive Augmented Reality Program for Balance and Mobility Rehabilitation in the Elderly: A Feasibility Study

Objective To improve lower extremity function and balance in elderly persons, we developed a novel, three-dimensional interactive augmented reality system (3D ARS). In this feasibility study, we assessed clinical and kinematic improvements, user participation, and the side effects of our system. Methods Eighteen participants (age, 56-76 years) capable of walking independently and standing on one leg were recruited. The participants received 3D ARS training during 10 sessions (30-minute duration each) for 4 weeks. Berg Balance Scale (BBS) and the Timed Up and Go (TUG) scores were obtained before and after the exercises. Outcome performance variables, including response time and success rate, and kinematic variables, such as hip and knee joint angle, were evaluated after each session. Results Participants exhibited significant clinical improvements in lower extremity balance and mobility following the intervention, as shown by improved BBS and TUG scores (p<0.001). Consistent kinematic improvements in the maximum joint angles of the hip and knee were observed across sessions. Outcome performance variables, such as success rate and response time, improved gradually across sessions, for each exercise. The level of participant interest also increased across sessions (p<0.001). All participants completed the program without experiencing any adverse effects. Conclusion Substantial clinical and kinematic improvements were observed after applying a novel 3D ARS training program, suggesting that this system can enhance lower extremity function and facilitate assessments of lower extremity kinematic capacity.

Effect of Proprioception Training of patient with Hemiplegia by Manipulating Visual Feedback using Virtual Reality: The Preliminary results

In this study, we confirmed proprioception training effect of patients with hemiplegia by manipulating visual feedback. Six patients with hemiplegia were participated in the experiment. Patients have trained with the reaching task with visual feedback without visual feedback for two weeks. Patients were evaluated with pre-, middle test and post-test with the task with and without visual feedback. In the results, the first-click error distance after the training of the reaching task was reduced when they got the training with the task removed visual feedback. In addition, the performance velocity profile of reaching movement formed an inverse U shape after the training. In conclusion, visual feedback manipulation using virtual reality could provide a tool for training reaching movement by enforcing to use their proprioception, which enhances reaching movement skills for patients with hemiplegia.

Proprioception rehabilitation training system for stroke patients using virtual reality technology

We investigated a virtual reality (VR) proprioceptive rehabilitation system that could manipulate the visual feedback of upper-limb during training and could do training by relying on proprioception feedback only. Virtual environments were designed in order to switch visual feedback on/off during upper-limb training. Two types of VR training tasks were designed for evaluating the effect of the proprioception focused training compared to the training with visual feedback. In order to evaluate the developed proprioception feedback virtual environment system, we recruited ten stroke patients (age: 54.7± 7.83years, on set: 3.29± 3.83 years). All patients performed three times PFVE task in order to check the improvement of proprioception function just before training session, after one week training, and after all training. In a comparison between FMS score and PFVE, the FMS score had a significant relationship with the error distance(r = -.662, n=10, p = .037) and total movement distance(r = -.726, n=10, p = .018) in PFVE. Comparing the training effect between in virtual environment with visual feedback and with proprioception, the click count, error distance and total error distance was more reduced in PFVE than VFVE. (Click count: p = 0.005, error distance: p = 0.001, total error distance: p = 0.007). It suggested that the proprioception feedback rather than visual feedback could be effective means to enhancing motor control during rehabilitation training. The developed VR system for rehabilitation has been verified in that stroke patients improved motor control after VR proprioception feedback training.

Development and Clinical Test of Virtual Reality Rehabilitation Training System for stiff-knee gait of stroke patients

Purposes of this paper are developing Virtual Reality rehabilitation system for hemiplegic patients who have stiff-knee gait and testing developed system. We developed rehabilitation system which is able to interact between system using PC camera and two markers. Scenario was composed simple task as crossing stepping-stone. In this paper, six males and three females with hemiplegic patients were participated. They trained seven times totally. Their performance was increasing about 30% in the last training session.

Measurement of Expression Characteristics in Emotional Situations using Virtual Reality

Expressions are a basic necessity for daily living, as they are required for managing relationships with other people. Conventional expression training has difficulty achieving an objective measurement, because their assessment depends on the therapists ability to assess a patients state or training effectiveness. In addition, it is difficult to provide emotional and social situations in the same manner for each training or assessment session. Virtual reality techniques can overcome shortcomings occurring in conventional studies by providing exact and objective measurements and emotional and social situations. In this study, we developed a virtual reality prototype that could present emotional situation and measure expression characteristics. Although this is a preliminary study, it could be considered that this study shows the potential of virtual reality as an assessment tool.