Questionnaire results of user experiences with wearable exoskeletons and their preferences for sensory feedback

BACKGROUND: Wearable exoskeletons can be a powerful tool for the facilitation of ambulation of complete Spinal Cord Injury (SCI) subjects, which has several psychological and physical advantages. However, exoskeleton control is difficult for this group of users and requires a long period of training. People with SCI not only lack the motor control, but also miss the sensory information from below the level of the lesion, which is for example very important in their perception of body posture and makes balancing with an exoskeleton difficult. It is hypothesized that through sensory substitution part of the missing sensory information can be provided and might thereby improve the control of an exoskeleton. However, it is not known which information would be most important to receive while using an exoskeleton and how this feedback should be provided.METHODS: To investigate the preferences of users of an exoskeleton, a questionnaire was filled out by 10 SCI subjects who underwent a training program with a commercial exoskeleton (ReWalk). The questionnaire consisted of questions about the use of the exoskeleton to identify which information is missing and which instructions from the therapists were needed to be able to control the exoskeleton. The second part of the questionnaire focused on the possibilities of sensory feedback and preferences for stimulation methods (auditory, vibrotactile or visual) and feedback timing (discrete or continuous) were investigated. Furthermore, six options for feedback parameters (step initiation, continuous and discrete gait phases, foot position and mediolateral and anteroposterior weight shift) were proposed and the respondents were asked to indicate their preferences.RESULTS: Three feedback parameters (feedback about mediolateral and anteroposterior weight shift and feedback about step initiation) were considered as possibly helpful by the respondents. Furthermore, there were slight preferences for the use of vibrotactile (over auditory and visual) and discrete (over continuous) feedback.CONCLUSIONS: The answers of the respondents on the optimal feedback parameters were rather variable and therefore it is recommended to let the users choose their preferred feedback system during a training session with several feedback options. However, there are slight preferences for the use of vibrotactile stimulation provided in a discrete way.</p

Functional Outcome After Successful Internal Fixation Versus Salvage Arthroplasty of Patients With a Femoral Neck Fracture

Objectives: To determine patient independency, health-related and disease-specific quality of life (QOL), gait pattern, and muscle strength in patients after salvage arthroplasty for failed internal fixation of a femoral neck fracture. Design: Secondary cohort study to a randomized controlled trial. Setting: Multicenter trial in the Netherlands, including 14 academic and nonacademic hospitals. Patients: Patients after salvage arthroplasty for failed internal fixation of a femoral neck fracture were studied. A comparison was made with patients who healed uneventfully after internal fixation. Intervention: None (observatory study). Main Outcome Measurements: Patient characteristics, SF-12, and Western Ontario McMaster osteoarthritis index scores were collected. Gait parameters were measured using plantar pressure measurement. Maximum isometric forces of the hip muscles were measured using a handheld dynamome

A protocol for the comparison of reaching gesture kinematics in physical versus immersive virtual reality

Virtual environments are increasingly being used for upper limb rehabilitation in post-stroke patients. However, still there is no clear evidence that the movements performed in virtual reality are comparable to those performed in the physical world from the kinematic point-of-view. The goal of the proposed study is thus to determine if aimed reaching movements made in a 3D ecological and immersive virtual environment – displayed through a Head Mounted Display (HMD) – are comparable to movements performed in the real world. The study foresees the realization of two comparable environmental settings representing the shelf of a supermarket. Three different groups of subjects (healthy young adults, healthy elderly, and post-stroke subjects, n=15 each) are asked to reach 5 times toward 9 targets in 3 different conditions: virtual reality, physical reality, and physical reality while holding a controller. Their movements are tracked with a stereo-photogrammetric motion capture system; movement times, peak velocities, and joint angles are then extracted for analysis. This protocol will allow comparing reaching movements, and also excluding of the effects related to holding a controller. A preliminary trial reveled the feasibility of the protocol, thus the experiment will be carried out in the next months. If results will be encouraging, VR should be considered in rehabilitative treatments as a useful means to elicit patients’ motivation, but also appropriate movement synergies, thus promoting a better recovery of upper limb functions

Advancing Analysis Techniques for Plantar Pressure Videos via Open-Access Contributions

While dynamic plantar pressure measurements are commonly used for clinical evaluation of gait-related problems, computational analysis techniques for these datasets are few and farbetween. To address this issue, we introduce an open-access database of plantar pressure videos for researchers to develop algorithms around