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Jeyeon Lee, Jeonghun Ku,
Kiwan Han,
Jinsick Park,
Hyeongrae Lee,
Kyung Ran Kim,
Eun Lee,
Masud Husain,
Kang Jun Yoon,
In Young Kim,
Dong Pyo Jang,
Sun I Kim
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ABSTRACT: Sustained attention is an essential brain function that enables a subject to maintain attention level over the time of a task. In previous work, the right inferior parietal lobe (IPL) has been reported as one of the main brain regions related to sustained attention, however, the right lateralization of vigilance/sustained attention is unclear because information about the network for sustained attention is traditionally provided by neglect patients who typically have right brain damage. Here, we investigated sustained attention by applying a virtual lesion technique, transcranial magnetic stimulation (TMS), over the left and right superior parietal lobe (SPL) and IPL. We used two different types of visual sustained attention tasks: spatial (location based) and non-spatial (feature based). When the participants performed the spatial task, repetitive TMS (rTMS) over either the right or left IPL induced a significant decrement of sustained attention causing a progressive increment of errors and response time. In contrast, participants' performance was not changed by rTMS on the non-spatial task. Also, omission errors (true negative) gradually increased with time on right and left IPL rTMS conditions, while commission errors (false positive) were relatively stable. These findings suggest that the maintenance of attention, especially in tasks regarding spatial location, is not uniquely lateralized to the right IPL, but may also involve participation of the left IPL.
Frontiers in Human Neuroscience 01/2013; 7:26. · 2.34 Impact Factor
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ABSTRACT: Aims: Reducing craving is a key to success in the treatment of alcohol dependence. The emotion circuit may be involved in pathological craving for alcohol. In this study, we investigated neural correlates of emotional involvement in craving in alcohol dependence. Methods: The study included 17 detoxified alcoholic patients and 25 social drinkers. We used functional magnetic resonance imaging to examine brain activation (blood oxygen level-dependent signals) while participants reported craving and emotion in response to visually presented, alcohol-related stimuli and emotional stimuli. Results: In the craving-rating paradigm, negative emotional stimuli as well as alcohol cues activated craving-related brain regions in alcoholic patients. Activations of the inferior parietal lobule and dorsolateral prefrontal cortex by negative emotional stimuli were negatively correlated with craving; meanwhile limbic activation was positively correlated with craving. For the emotion paradigm, greater limbic activation was evident by alcohol-related stimuli in the alcohol-dependent group. Conclusions: Our findings constitute neural evidence for emotional involvement in pathological craving for alcohol, underscoring the importance of emotion management in abstinent alcoholic patients for relapse prevention.
Alcohol and Alcoholism 12/2012; · 2.95 Impact Factor
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ABSTRACT: To demonstrate the usefulness of 3-tesla (3T) magnetic resonance imaging (MRI) including T2-weighted imaging (T2WI), diffusion weighted imaging (DWI), time-of-flight (TOF) magnetic resonance angiography (MRA), T2(*)-weighted gradient recalled echo (GRE), and susceptibility weighted imaging (SWI) in diagnosing brain death.
Magnetic resonance imaging findings for 10 patients with clinically verified brain death (group I) and seven patients with comatose or stuporous mentality who did not meet the clinical criteria of brain death (group II) were retrospectively reviewed.
Tonsilar herniation and loss of intraarterial flow signal voids (LIFSV) on T2WI were highly sensitive and specific findings for the diagnosis of brain death (p < 0.001 and < 0.001, respectively). DWI, TOF-MRA, and GRE findings were statistically different between the two groups (p = 0.015, 0.029, and 0.003, respectively). However, cortical high signal intensities in T2WI and SWI findings were not statistically different between the two group (p = 0.412 and 1.0, respectively).
T2-weighted imaging, DWI, and MRA using 3T MRI may be useful for diagnosing brain death. However, SWI findings are not specific due to high false positive findings.
Korean journal of radiology: official journal of the Korean Radiological Society 09/2012; 13(5):541-9. · 1.32 Impact Factor
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ABSTRACT: Background: Auditory hallucinations often influence schizophrenia patients in many aspects. In order to develop effective behavioral interventions for overcoming enduring auditory hallucinations, it is necessary to understand how the annoying symptom affects the daily lives of the patients. This study evaluated the effect of hearing unusual voices on performing the activities of daily life in schizophrenia patients. Methods: Eighteen hallucinating patients, 18 nonhallucinating patients and 20 normal controls performed the virtual daily-life task of packing 8 items for travel under 3 conditions: (1) without unusual voices and without avatars, (2) with unusual voices and without avatars and (3) with unusual voices and with avatars. Task completion time and the number of times the packing list was checked were recorded as a measure of the task performance. Results: When exposed to unusual voices without avatars, hallucinating patients checked the packing list fewer times than nonhallucinating patients, and they required longer to complete the task, as positive and negative symptoms were worse. Subjective responses to unusual voices were stronger in hallucinating patients than in nonhallucinating patients. Conclusions: Daily-life activities of hallucinating patients may be less easily influenced by odd auditory stimuli in a nonsocial situation than those of nonhallucinating patients; however, hallucinating patients may feel more strongly affected by unusual voices. To better evaluate and thereby understand the difficulties faced by hallucinating patients in their daily life, the discrepancies between objective and subjective measures as well as social situations should be taken into consideration.
Psychopathology 07/2012; 45(6):352-60. · 1.82 Impact Factor
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ABSTRACT: Most patients with schizophrenia suffer from various types of hallucinations, which commonly produce distress, functional disability or behavioral dyscontrol. The neural process of adapting to hallucinations in patients with schizophrenia remains unknown.
Functional magnetic resonance imaging (MRI) responses to an unusual threatening visual stimulus designed to simulate a hallucinatory experience were compared between 16 patients with schizophrenia and 17 healthy controls. Linear and quadratic repetition-variant as well as repetition-invariant responses to the stimulus were compared between the two groups.
Repetition-invariant responses were similar between patients with schizophrenia and healthy controls. Patients with schizophrenia exhibited a linear activation pattern in the anterior cingulate, whereas healthy controls exhibited a parabolic activation pattern in the anterior prefrontal cortex, occipito-temporal junction and amygdala.
These results provide us with a better understanding of the neural processes involved in gaining insight into unreality. Patients with schizophrenia may use a salience-related region instead of reality monitoring-related regions to react to the unusual stimuli, and this peculiarity of the neural processes may be related to vulnerability to psychosis.
Journal of psychiatric research 07/2012; 46(10):1318-25. · 3.72 Impact Factor
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ABSTRACT: The anterior insula has been proposed to play a crucial role in eating disorders. However, it is still poorly understood how the anterior insula is involved in anorexia nervosa (AN) and bulimia nervosa (BN), which are characterized by opposite motivational responses to food. We applied a cue-reactivity paradigm using blood oxygen level-dependent functional magnetic resonance imaging in women with AN (N=18) and BN (N=20) and age-matched healthy controls (N=20). We defined the left anterior insula as a region-of-interest and performed seed-based functional connectivity and effective connectivity MRI analysis. In response to food images compared to non-food images, both the AN group and BN group demonstrated increased activity in the left anterior insula. In the AN group, the left anterior insula demonstrated significant interactions with the right insula and right inferior frontal gyrus. In the BN group, the left anterior insula demonstrated significant interactions with the medial orbitofrontal cortex. The distinct patterns of functional and effective connectivity of the anterior insula may contribute to the different clinical features of AN and BN.
Neuroscience Letters 06/2012; 521(2):152-7. · 2.11 Impact Factor
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ABSTRACT: To delineate the changes in corticospinal excitability when individuals are asked to exercise their hand using observation, motor imagery, voluntary exercise, and exercise with a mirror.
The participants consisted of 30 healthy subjects and 30 stroke patients. In healthy subjects, the amplitudes and latencies of motor evoked potential (MEP) were obtained using seven conditions: (A) rest; (B) imagery; (C) observation and imagery of the hand activity of other individuals; (D) observation and imagery of own ipsilateral hand activity; (E) observation and imagery of the hand activity of another individual with a mirror; (F) observation and imagery of own symmetric ipsilateral hand activity (thumb abduction) with a mirror; and (G) observation and imagery of own asymmetric ipsilateral hand activity (little finger abduction) with a mirror. In stroke patients, MEPs were obtained in the A, C, D, E, F conditions.
In both groups, increment of the percentage MEP amplitude (at rest) and latency decrement of MEPs were significantly higher during the observation of the activity of the hand of another individual with a mirror and during symmetric ipsilateral hand activity on their own hand with a mirror than they were without a mirror. In healthy subjects, the increment of percentage MEP amplitude and latency decrement were significantly higher during the observation of the symmetric ipsilateral hand activity with a mirror compared to the observation of the activity of the asymmetric ipsilateral hand with a mirror of their own hand.
In both groups, corticospinal excitability was facilitated by viewing the mirror image of the activity of the ipsilateral hand. These findings provide neurophysiological evidence supporting the application of various mirror imagery programs during stroke rehabilitation.
Annals of rehabilitation medicine. 12/2011; 35(6):747-58.
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ABSTRACT: Although social skills training (SST) is an effective approach for improving social skills for schizophrenia, the motivational deficit attenuates its efficacy. Virtual reality (VR) applications have allowed individuals with mental disabilities to enhance their motivation for rehabilitation. We compared SST using VR role-playing (SST-VR) to SST using traditional role-playing (SST-TR). This randomized, controlled trial included 91 inpatients with schizophrenia who were assigned to either SST-VR (n=46) or SST-TR (n=45). Both groups were administered over 10 semiweekly group sessions. An experienced, blinded rater assessed vocal, nonverbal and conversational skills. We also obtained data on motivation for SST and various social abilities. Throughout the 10 sessions, the SST-VR group (n=33) showed greater interest in SST and generalization of the skills than the SST-TR group (n=31). After SST, the SST-VR group improved more in conversational skills and assertiveness than the SST-TR group, but less in nonverbal skills. The VR application in role-plays of SST for schizophrenia may be particularly beneficial in terms of improving the conversational skills and assertiveness, possibly through its advantages in enhancing motivation for SST and generalization of the skills, and thus it may be a useful supplement to traditional SST.
Psychiatry Research 04/2011; 189(2):166-72. · 2.52 Impact Factor
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ABSTRACT: 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.
The Journal of nervous and mental disease 11/2010; 198(11):829-35. · 1.77 Impact Factor
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ABSTRACT: Resting-state functional MRI (fMRI) is now providing further understanding of neuropsychiatric illnesses. However, its practical applicability in the clinical realms is still questionable. Here we report three consecutive followed-up resting-state fMRI data in a single case with Wernicke encephalopathy before and after high-dose thiamine replacement therapy ranging over 20 months. We measured the mammillothalamic functional connectivity strength between the first ROI (mammillary body) and a voxel which showed the highest co-activation among voxels within the anterior thalamus (the second ROI) to enhance the specificity of the functional connectivity data. We found that the time-series changes in the mammillothalamic functional connectivity generally paralleled to the changes in delayed verbal and nonverbal recall memory scores in the left and right hemisphere, respectively. Among these, the left-side connectivity and delayed verbal recall score seemed to be related to the overall clinical status change. Modified directed transfer function (dDTF) analysis also identified significant information flows with mammillary-to-thalamic direction except at the acute illness state. Our findings, though preliminary in nature, suggest the practical applicability of resting-state fMRI to trace an effect of thiamine replacement therapy on the memory tract function in Wernicke encephalopathy at single-patient level.
Neuroscience Letters 08/2010; 479(3):257-61. · 2.11 Impact Factor
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ABSTRACT: The degree at which individuals maintain behavioral strategies during uncertain conditions varies widely; however, the neural bases of these individual differences remain unclear. This study examines the functional connectivity of the orbitofrontal cortex during a decision-making task using functional magnetic resonance imaging. The strength of the functional connectivity observed between the medial orbitofrontal cortex and the nucleus accumbens was determined to be correlated with the number of persistent responses made during the decision-making task. It is proposed that top-down control of the orbitofrontal cortex over the ventral striatum is a critical component underlying individual differences in decision making during uncertain conditions.
Neuroreport 03/2010; 21(7):502-6. · 1.66 Impact Factor
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ABSTRACT: The objective of this study was to explore the possibility of the use of Virtual Reality Functional Skills Assessment (VRFSA) in a future regular clinical trial, as well as to report a preliminary result about effectiveness of atypical antipsychotics to social competence in schizophrenia.
We developed the VRFSA that measured subjects' performances automatically and used analogue scale rather than Likert scale. Twenty-four female patients with paranoid schizophrenia and 15 healthy females were recruited. This was a 6-week, randomized, open-label, and flexible dose study, and 2 treatments (baseline versus post-treatment) x 2 skills phases (receptive versus expressive) x 2 patient groups (aripiprazole versus risperidone) analysis of variance was used in the final analysis.
There was a significant difference in the VRFAS between the patients and the healthy subjects (p < 0.05). Eighteen patients were included in the final analysis. We found larger treatment effect than those found in previous studies, and significant treatment x skills phase x group interaction effect on the VRFAS.
Our results suggest that the VRFAS is strongly sensitive to changes in social competence and thus especially beneficial in short-term clinical trials. In addition, atypical antipsychotics can improve social competence and differentially improve receptive skills and expressive skills in schizophrenia.
Human Psychopharmacology Clinical and Experimental 11/2009; 24(8):619-27. · 2.48 Impact Factor
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ABSTRACT: Virtual reality may be a good alternative method for measuring personal space and overcoming some limitations in previous studies on the social aspects of schizophrenia. Using this technology, we aimed to investigate the characteristics of personal space in patients with schizophrenia and evaluate the relationship between their social behaviors and schizophrenic symptoms. The distance from a virtual person and the angle of head orientation while talking to a virtual person in a virtual environment were measured in 30 patients with schizophrenia and 30 normal controls. It was found that patients with schizophrenia had longer distances and larger angles than did normal controls. The severity of the negative syndrome had significant inverse correlations with the distance from the angry and neutral virtual persons and with the angle of head orientation toward the happy and angry virtual persons, suggesting that negative symptoms may have a close relationship with personal space, including distancing and eye gaze. The larger personal space of patients may reflect their discomfort in close situations or cognitive deficits. Showing these profiles to patients could help them realize the amount of personal space they need.
Psychiatry Research 10/2009; 169(3):197-202. · 2.52 Impact Factor
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ABSTRACT: 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.
The Journal of nervous and mental disease 07/2009; 197(6):412-8. · 1.77 Impact Factor
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ABSTRACT: 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.
Twenty participants diagnosed with stroke caused by unilateral brain lesions were enrolled to assess the VET program's 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 Kim's 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.
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.
The VET-based cognitive assessment program showed adequate reliability and validity as a method of cognitive assessment in patients after stroke.
American journal of physical medicine & rehabilitation / Association of Academic Physiatrists 06/2009; 88(9):702-10. · 1.56 Impact Factor
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ABSTRACT: 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 therapist's ability to assess a patient's 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.
Virtual Reality Conference, 2009. VR 2009. IEEE; 04/2009
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ABSTRACT: 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.
Virtual Reality Conference, 2009. VR 2009. IEEE; 04/2009
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ABSTRACT: 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 therapist's ability to assess a patient's 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.
Computers in biology and medicine 02/2009; 39(2):173-9. · 1.27 Impact Factor
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ABSTRACT: Dysfunctional emotional processing affects social functioning in patients with schizophrenia. However, the relationship between emotional perception and response in social interaction has not been elucidated. Twenty-seven patients with schizophrenia and 27 normal controls performed a virtual reality social encounter task in which they introduced themselves to avatars expressing happy, neutral, or angry emotions while verbal response duration and onset time were measured and perception of emotional valence and arousal, and state anxiety were rated afterwards. Self-reported trait-affective scale scores and the Positive and Negative Syndrome Scale (PANSS) ratings were also obtained. Patient group significantly underestimated the valence and arousal of angry emotions expressed by an avatar. While valence and arousal ratings of happy avatars were comparable between groups, patient group reported significantly higher state anxiety in response to happy avatars. State anxiety ratings significantly decreased from encounters with neutral to happy avatars in normal controls while no significant decrease was observed in the patient group. The Social Anhedonia Scale and PANSS negative symptom subscale scores (blunted affect, emotional withdrawal, and passive/ apathetic social withdrawal items) were significantly correlated with state anxiety ratings of the encounters with happy avatars. These results suggest that patients with schizophrenia have interference with the experience of pleasure in social interactions which may be associated with negative symptoms.
Psychiatry Interpersonal & Biological Processes 02/2009; 72(1):79-93. · 3.16 Impact Factor
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ABSTRACT: There is still debate over the neural mechanisms underlying pathogenic and even recovery processes of Wernicke's encephalopathy. Therefore, we attempted to validate the usefulness of resting-state functional connectivity analysis in assessing memory function and its neural correlation with the mammillothalamic tract in patients recovering from Wernicke's encephalopathy. Seven chronic alcoholics recovering from Wernicke's encephalopathy, 14 alcoholic comparisons without Wernicke's encephalopathy, and 14 healthy comparisons underwent functional connectivity MRI scans, as well as verbal and non-verbal memory tests after at least a 1 month abstinence from alcohol. Resting-state functional connectivity strength between the anterior thalamus and the mammillary bodies was investigated by calculating temporal correlations in magnetic resonance signal levels between the two regions during a 5-min passive viewing task. The mean values of the functional connectivity strength between the left anterior thalamus and the ipsilateral mammillary body differed significantly between Wernicke's encephalopathy patients and healthy comparisons (P = 0.014). This connectivity strength in alcoholic comparisons fell between those of the former two groups, with a significant difference from that of healthy comparisons (P = 0.038). In addition, the strength of this left-sided functional connectivity significantly correlated with delayed verbal recall scores (r = 0.771, P = 0.042) and verbal recognition score (r = 0.825, P = 0.022) in patients with Wernicke's encephalopathy. Our findings indicate that memory function in patients recovering from Wernicke's encephalopathy parallels the level of the mammillothalamic functional connectivity; this supports the usefulness of resting-state functional connectivity analysis as a practical alternative to pathological examination of the mammillothalamic tract in living patients with Wernicke's encephalopathy.
Brain 12/2008; 132(Pt 2):369-76. · 9.46 Impact Factor
