Gyu Hyun Kwon

Which motor cortical region best predicts imagined movement

In brain-computer interfacing (BCI), motor imagery is used to provide a gateway to an effector action or behavior. However, in contrast to the main functional role of the primary motor cortex (M1) in motor execution, the M1s involvement in motor imagery has been debated, while the roles of secondary motor areas such as the premotor cortex (PMC) and supplementary motor area (SMA) in motor imagery have been proposed. We examined which motor cortical region had the greatest predictive ability for imagined movement among the primary and secondary motor areas. For two modes of motor performance, executed movement and imagined movement, in 12 healthy subjects who performed two types of motor task, hand grasping and hand rotation, we used the multivariate Bayes method to compare predictive ability between the primary and secondary motor areas (M1, PMC, and SMA) contralateral to the moved hand. With the distributed representation of activation, executed movement was best predicted from the M1 while imagined movement from the SMA, among the three motor cortical regions, in both types of motor task. In addition, the most predictive information about the distinction between executed movement and imagined movement was contained in the M1. The greater predictive ability of the SMA for imagined movement suggests its functional role that could be applied to motor imagery-based BCI.

EEG response varies with lesion location in patients with chronic stroke.

BackgroundBrain activation differs according to lesion location in functional magnetic resonance imaging (fMRI) studies, but lesion location-dependent electroencephalographic (EEG) alterations are unclear. Because of the increasing use of EEG-based brain-computer-interface rehabilitation, we examined lesion location-dependent EEG patterns in patients with stroke while they performed motor tasks.MethodsTwelve patients with chronic stroke were divided into three subgroups according to their lesion locations: supratentorial lesions that included M1 (SM1+), supratentorial lesions that excluded M1 (SM1-), and infratentorial (INF) lesions. Participants performed three motor tasks [active, passive, and motor imagery (MI)] with supination and grasping movements. The hemispheric asymmetric indexes, which were calculated with laterality coefficients (LCs), the temporal changes in the event-related desynchronization (ERD) patterns in the bilateral motor cortex, and the topographical distributions in the 28-channel EEG patterns around the supplementary motor area and bilateral motor cortex of the three participant subgroups were compared with those of the 12 age-matched healthy controls.ResultsThe SM1+ group exhibited negative LC values in the active and MI motor tasks, while the other patient subgroups exhibited positive LC values. Negative LC values indicate that the ERD/ERS intensity of the ipsilateral hemisphere is higher than the contralateral hemisphere, whereas positive LC values indicate that the ERD/ERS intensity of the contralateral hemisphere is higher than the ipsilateral hemisphere. The LC values of SM1+ and healthy controls differed significantly (rank-sum test, p < 0.05) in both the supination and grasping movements in the active task. The three patient subgroups differed distinctly from each other in the topography analysis.ConclusionsThe hemispheric asymmetry and topographic characteristics of the beta band power patterns in the patients with stroke differed according to the location of the lesion, which suggested that EEG analyses of neurorehabilitation should be implemented according to lesion location.

Assessment of Cognitive Engagement in Stroke Patients From Single-Trial EEG During Motor Rehabilitation

We propose a novel method for monitoring cognitive engagement in stroke patients during motor rehabilitation. Active engagement reflects implicit motivation and can enhance motor recovery. In this study, we used electroencephalography (EEG) to assess cognitive engagement in 11 chronic stroke patients while they executed active and passive motor tasks involving grasping and supination hand movements. We observed that the active motor task induced larger event-related desynchronization (ERD) than the passive task in the bilateral motor cortex and supplementary motor area (SMA). ERD differences between tasks were observed during both initial and post-movement periods (p <; 0.01). Additionally, differences in beta band activity were larger than differences in mu band activity (p <; 0.01). EEG data was used to help classify each trial as involving the active or passive motor task. Average classification accuracy was 80.7±0.1% for grasping movement and 82.8±0.1% for supination movement. Classification accuracy using a combination of movement and post-movement periods was higher than in other cases (p <; 0.05). Our results support using EEG to assess cognitive engagement in stroke patients during motor rehabilitation.

Predicting the Performance of Motor Imagery in Stroke Patients Multivariate Pattern Analysis of Functional MRI Data

Background. In a brain–computer interface for stroke rehabilitation, motor imagery is a preferred means for providing a gateway to an effector action or behavior. However, stroke patients often exhibit failure to comply with motor imagery, and therefore their motor imagery performance is highly variable. Objective. We sought to identify motor cortical areas responsible for motor imagery performance in stroke patients, specifically by using a multivariate pattern analysis of functional magnetic resonance imaging data. Methods. We adopted an imaginary finger tapping task in which motor imagery performance could be monitored for 12 chronic stroke patients with subcortical infarcts and 12 age- and sex-matched healthy controls. We identified the typical activation pattern elicited for motor imagery in healthy controls, as computed over the voxels within each searchlight in the motor cortex. Then we measured the similarity of each individual’s activation pattern to the typical activation pattern. Results. In terms of activation levels, the stroke patients showed no activation in the ipsilesional primary motor cortex (M1); in terms of activation patterns, they showed lower similarity to the typical activation pattern in the area than the healthy controls. Furthermore, the stroke patients were better able to perform motor imagery if their activation patterns in the bilateral supplementary motor areas and ipsilesional M1 were close to the typical activation pattern. Conclusions. These findings suggest functional roles of the motor cortical areas for compliance with motor imagery in stroke, which can be applied to the implementation of motor imagery–based brain–computer interface for stroke rehabilitation.

Socio-cognitive aspects of interoperability: Understanding communication task environments among different organizations

Emergency communication systems (ECS) are a key element in collaborations among different public safety organizations. The need for interoperability in emergency communication systems has hastened the development of interoperable communication technology that is an enabling technology to automatically identify environmental variables including appropriate radio frequencies and to connect different networks used by different organizations. Even though the technology has been researched from many perspectives and has shown that is possible to connect different organizations, there still remain many issues in terms of socio-cognitive aspects. Thus, this study examines the socio-cognitive dimensions of interoperability, which equal the technical dimensions of the problem in importance. The existential-phenomenological study reported here used semistructured interviews to reconceptualize interoperability in the public safety communication domain. Based on 11 interviews with public safety workers, five important factors were identified that have a major impact on the effectiveness of interoperable groups: information sharedness, operational awareness, communication readiness, adaptiveness, and coupledness. Based on these main concepts, high-level suggestions are provided to guide the design of a new public safety communication system. The results can be directly applied to identify the requirements of communication systems and can be extended to design collaboration systems under stressful environments.

A rehabilitation device to improve the hand grasp function of stroke patients using a patient-driven approach

This paper proposes a robotic hand rehabilitation device for grasp training. The device is designed for stroke patients to train and recover their hand grasp function in order to undertake activities of daily living (ADL). The device consists of a control unit, two small actuators, an infrared (IR) sensor, and pressure sensors in the grasp handle. The advantages of this device are that it is small in size, inexpensive, and available for use at home without specialists supervision. In addition, a novel patient-driven strategy based on the patients movement intention detected by the pressure sensors without bio-signals is introduced. Once the system detects a patients movement intention, it triggers the robotic device to move the patients hand to form the normal grasping behavior. This strategy may encourage stroke patients to participate in rehabilitation training to recover their hand grasp function and it may also enhance neural plasticity. A user study was conducted in order to investigate the usability, acceptability, satisfaction, and suggestions for improvement of the proposed device. The results of this survey included positive reviews from therapists and a stroke patient. In particular, therapists expected that the proposed patient-driven mode can motivate patients for their rehabilitation training and it can be effective to prevent a compensational strategy in active movements. It is expected that the proposed device will assist stroke patients in restoring their grasp function efficiently.

E-CORE (Embodied COgnitive REhabilitation): A Cognitive Rehabilitation System Using Tangible Tabletop Interface

This paper presents a novel cognitive rehabilitation system with a tangible tabletop interface allowing the users to perform cognitive tasks intuitively by their hands. The system consists of a tabletop display with multi-touch function and several tangible objects working on the tabletop interface. We named the system E-CORE (Embodied COgnitive REhabilitation) since it reinforces the coupling of human body and cognition. E-CORE is designed to improve both cognitive functions and gross motor skills of older adults by practicing artificial daily life activities such as cookie making.

A Systematic Underpinning and Framing of the Servicescape: Reflections on Future Challenges in Healthcare Services

Ever since Bitner defined the term “servicescape” as the physical environment in which the service is assembled, several scholars have attempted to better understand the impact of the built environment in the context of different service settings. While servicescape is a topic of increasing academic interest among scholars and practitioners, most studies in the area are dedicated to understanding the built environment of hedonic service. More studies are needed to examine utilitarian servicescape and in this paper, we have focused on the healthcare environment. This study aims to identify the gap in servicescape and healthscape studies by providing a theoretical structure of the current servicescape literature and comprehend the academic differences between hedonic servicescape and utilitarian healthscape studies. After reviewing 44 selected papers based on rigorous criteria, we: (1) framed the servicescape factors; (2) analyzed the servicescape literature from the perspectives of terminologies, research fields, methodologies, and frameworks; and (3) identified the current paths of healthscape research. Through this work, we highlight the significance of adopting different dimensions and factors to evaluate the distinguished service environment by the servicescape type and propose several research agendas for future studies on healthscapes. The research findings can contribute to a deep understanding of healthscapes and can introduce a new viewpoint for interpreting the servicescape in diversified service settings.

Optimal User Interface Parameters for Dual-Sided Transparent Screens in Layered Window Conditions

In this research, we assess a set of optimal user interface parameters for a dual-sided transparent display in a collaborative working environment. To provide an experiment setup, we develop a prototype that simulates a dual-sided transparent display using two conventional displays and associated simulation software. The user interface parameters controlled in the experiment include the transparency level and the overlapped or layered size of foreground and background user interface windows, where a target marker being searched by subjects is presented along with distraction markers. To evaluate the optimal parameter setting, we measure the response time and correct response rate from the subject input to both the foreground and background displays.i¾?From the pilot study, we found that appropriate levels of transparency and windows overlapping potentially enhance the visibility of a user interface realized on layered multiple windows.i¾?Based on this finding, we propose an extended user research, where a depth factor and a contour effect are employed in addition to the user interface parameters, which may enhance the user response time especially in cases where the windows are highly overlapped.

Finding Satisfactory Transparency: An Empirical Study on Public Transparent Displays in a Shop Context

This paper focuses on designing an affective user interface for public transparent displays in a shop context. In order to maintain harmonious view and satisfactory experience, the relationship between the information and transparency needs to be considered. Therefore, in this paper, we investigate different levels of transparency for determining their appropriateness with regard to users proximity. Two user studies show that 25% transparency is more satisfactory in closer proximity while 50% transparency offers more harmonious view in a distant context. Our findings on satisfactory transparency can be applied to a basis of further investigation for public transparent displays, especially in a shop context.