Kiwan Han

Virtual environment training system for rehabilitation of stroke patients with unilateral neglect: crossing the virtual street.

In this paper, we propose a system for training of stroke patients with unilateral neglect by using technology of virtual reality (VR). The proposed system is designed to compensate for unilateral neglect. This system contains the calibration of unilateral neglect and the training of this disease. The calibration procedure is implemented by aligning the virtual object at a subjective middle line. The training procedure is implemented by completing the missions that are used to keep the virtual avatar safe during crossing the street in a virtual environment. The results of this study show that the proposed system is effective to train unilateral neglect. The left to right ratio scores extracted from this system gradually decrease as the sessions of training are repeated. To validate the VR system parameters, the parameters are analyzed by correlation with those of traditional unilateral neglect assessment methods (such as the line bisection test and the cancellation test).

Development and clinical trial of virtual reality-based cognitive assessment in people with stroke: preliminary study.

Stroke and traumatic brain injury affect an increasing number of people, many of whom retain permanent damage in cognitive functions. Conventionally, cognitive function has been assessed by a paper-based neuropsychological evaluation. However these test environments differ substantially from everyday life. This problem can be overcome by using virtual reality (VR) to objectively evaluate behaviors and cognitive function in simulated daily activities. With our virtual shopping simulation, we compared people who had undergone a stroke with control participants in an immersive VR program that used a head-mounted display (HMD). We evaluated user satisfaction with the tests, complications, and the user interface. Significant differences were consistently found between the stroke group and the control group for the following tasks: stage 1 performance index, interaction error; stage 2 delayed recognition memory score, attention index; and stage 3 executive index (p < 0.001). Perceptive dysfunction, visuospatial dysfunction, level of computer experience, and level of education affected the performance of the stroke group. The frequency of complications in the stroke group, calculated using the cut-off score for the Simulator Sickness Questionnaire, was 9.6% for nausea, 41.9% for oculomotor complications, and 25.8% for disorientation. The frequency of complications between the stroke and control groups was not significantly different. Thirty-five percent of participants in the stroke group and 13% in the control group reported difficulties with using the joystick. This computer-generated VR-based cognitive test shows promise in assessing cognitive function in patients with stroke. More refinements are needed in the user interface and the projection methods.

VR-Based Conversation Training Program for Patients with Schizophrenia: A Preliminary Clinical Trial

Schizophrenia is a devastating mental illness and is characterized by hallucinations and delusions as well as social skills deficits. Generally, social skills training designed to help patients develop social skills includes role-playing, but this form of training has typical shortcomings, which are largely due to a trainers difficulties to project emotion. Virtual reality (VR)-based techniques have the potential to solve these difficulties, because they provide a computer-generated but realistic three-dimensional world and humanlike avatars that can provide emotional stimuli. In this paper, we report on a method of implementing virtual environments (VEs) in order to train people with schizophrenia to develop conversational skills in specific situations, which could overcome the shortcomings of or complement conventional role-playing techniques. The paper reports the efficacy of the proposed approach in a preliminary clinical trial with 10 patients with schizophrenia.

Assessment of post-stroke extrapersonal neglect using a three-dimensional immersive virtual street crossing program

Kim DY, Ku J, Chang WH, Park TH, Lim JY, Han K, Kim IY, Kim SI. Assessment of post‐stroke extrapersonal neglect using a three‐dimensional immersive virtual street crossing program
Acta Neurol Scand: 2010: 121: 171–177.
© 2009 The Authors Journal compilation

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.

Development of a computer-based behavioral assessment of checking behavior in obsessive-compulsive disorder

OBJECTIVE The goal of the current study was to develop and obtain preliminary psychometric data for a computer-based behavioral measure of compulsive checking behavior in a sample of patients with obsessive-compulsive disorder (OCD). METHOD We examined performance on a novel behavioral measure in 30 patients with OCD and 27 matched healthy controls. In the computerized assessment, participants navigated through two virtual environments (home and office) using a joystick and head-mounted display. The experiment consisted of three phases: training, distraction, and the main task. After the training and distraction phases, participants were instructed to check the virtual environments freely as if they were in their natural environment. Primary dependent variables in the current study included several indices of frequency and duration of checking behaviors. We examined construct validity for the task by comparing the novel behavioral measures with standardized self-report and interviewer-rated measures. RESULTS Results indicated that (1) OCD patients demonstrated significantly greater problems with compulsive checking compared to controls, and (2) performance on the task was positively correlated with both self-reported symptoms and interviewer-rated measures associated with OCD. CONCLUSIONS This study provides preliminary data to support the use of this task as a new possible behavioral measure of compulsive checking behavior in OCD. If we merge the traditional behavioral research with this novel and ecologically valid method, it could improve the assessment of OCD in both clinical and research setting.

Nonverbal social behaviors of patients with bipolar mania during interactions with virtual humans.

It has been proposed that positive emotional biases could make bipolar manic (BM) patients maintain abnormally approaching behaviors during social interactions. To test this hypothesis, we measured interpersonal distance (IPD) and gaze angle of BM patients and normal controls (NCs) during social interaction in immersive virtual environment. Overall, IPDs of BM patients (n = 20) were greater than those of normal controls (n = 20). The IPD difference was even greater between NCs and BM patients with psychotic features (n = 11) than those without psychotic features (n = 9). Regardless of the presence of psychotic features, BM patients averted their gazes more than NCs, and even more while speaking than while listening. Our results might suggest negativistic social cognition of bipolar patients, as was previously found even during a manic phase, or the role of paranoid symptoms in avoidant social behaviors, in agreement with prior studies with schizophrenic patients. Use of proper space and gaze might have psychotherapeutic implication in developing secure, two-person relationship with bipolar patients regardless of the presence of disrupting manic symptoms.

Deficits in eye gaze during negative social interactions in patients with schizophrenia.

Impaired social functioning has been reported in patients with schizophrenia. This study aimed to examine characteristics of interpersonal behaviors in patients with schizophrenia during various social interactions using the virtual reality system. Twenty-six patients and 26 controls engaged in the virtual conversation tasks, including 3 positive and 3 negative emotion-laden conversations. Eye gaze and other behavioral parameters were recorded during the listening and answering phases. The amount of eye gaze was assessed as smaller in the patients than in the controls. A significant interaction effect of group status and emotional type was found for the listening phase. The amount of eye gaze in the patients inversely correlated with self-rated scores of assertiveness for the listening phase. These results suggest that the patients displayed inadequate levels of augmentations in eye gaze during negative emotional situations. These deficits should be considered in the treatment and social skills training for patients with schizophrenia.

Virtual reality prototype for measurement of expression characteristics in emotional situations

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.

Validity and Reliability of Cognitive Assessment Using Virtual Environment Technology in Patients with Stroke

Ku J, Lee JH, Han K, Kim SI, Kang YJ, Park ES: Validity and reliability of cognitive assessment using virtual environment technology in patients with stroke. Objectives: We assessed the validity and reliability of a virtual environment technology (VET)-based cognitive assessment program that was developed as a measurement tool of cognitive abilities in patients after a stroke. Design: Twenty participants diagnosed with stroke caused by unilateral brain lesions were enrolled to assess the VET programs validity and test-retest reliability. Participants underwent evaluation by paper-based neuropsychological tests including the Korean Mini-Mental Status Examination, the Korean-Wechsler Adult Intelligence Scale, the Motor Free Visual Perception Test, Rey-Kim Memory Test, and Kims Frontal-Executive Neuropsychologic Test as well as the VET-based cognitive assessment. Major variables and indices of the VET program were calculated. The VET program validity was evaluated using a simple correlation analysis between variables from the VET program and conventional paper-based neuropsychological measurements, and the reliability was evaluated by investigating the test-retest correlation coefficients. Results: Major variables and indices of the VET program in patients with stroke correlated significantly with the related scores of paper-based neuropsychological tests. In addition, the test-retest reliability analysis revealed that the correlation coefficients ranged from 0.528 to 0.926. Conclusion: The VET-based cognitive assessment program showed adequate reliability and validity as a method of cognitive assessment in patients after stroke.