Stroke-related gait impairments reduce walking ability, independence, and quality of life, creating a need for accessible rehabilitation technologies. Passive cable-driven systems may provide a lightweight and low-cost alternative to conventional robotic gait devices, but the influence of their mechanical settings on gait behavior remains unclear. This study investigated how elastic cable pretension and attachment location influence gait kinematics and muscle activity during walking with the Passive Mechanical Add-on for Treadmill Exercise (P-MATE), a passive gait rehabilitation device. Cable pretension refers to the initial tension applied to the elastic cables before movement, while two attachment configurations were evaluated for force transmission to the lower limb: a proximal cuff around the lower leg and a distal bandage around the foot. Seven healthy adults walked on a treadmill under three pretension conditions (10 N, 30 N, and 50 N) and both attachment configurations while kinematic and electromyographic (EMG) data were recorded. The 30 N pretension condition produced gait patterns closest to unassisted walking, whereas both lower and higher pretension levels caused greater deviations in step length, step width, swing velocity, and knee motion. Increasing pretension also increased step width and reduced knee range of motion. Compared to the cuff configuration, the bandage configuration produced greater step width and lower knee range of motion, suggesting stronger guidance of lower-limb movement due to distal force application. Muscle activation patterns were largely preserved, although muscle-specific adaptations were observed under higher pretension conditions. These findings demonstrate that both cable pretension and attachment location substantially influence gait behavior during walking with the P-MATE and highlight the importance of personalized device settings in passive gait rehabilitation. ... Read more

Conventional post-stroke gait rehabilitation is labour-intensive, often requiring multiple therapists for physical assistance. Both robotic and aquatic therapies have been proposed to address this: robots can reduce therapist workload and provide adaptable feedback, while aquatic environments offer apparent weight reduction, improved balance, and muscle strengthening. Virtual aquatic therapy combines both approaches by haptically rendering the fluid dynamics of virtual water. In addition to the sagittal degrees of freedom offered by existing implementations, the treadmill-based exoskeleton used in this study enables hip abduction and lateral pelvis movements. A physics-based fluid rendering model is developed to compute drag and buoyancy forces acting on virtual legs moving through fluids. To match the real-world setup, the model simulates treadmill walking rather than the conventional free walking and includes the additional axes of motion. Simulations confirm that the model's outputs are consistent with the literature and scale properly with movement speed, submersion depth and the type of fluid being rendered. Through a proof-of-concept experiment, the successful integration into the exoskeleton’s control framework is validated, demonstrating the feasibility of rendering diverse fluid environments with this system. ... Read more

Background: Spinal cord injury (SCI) disrupts brain–peripheral nervous system communication, causing total or partial loss of motor, sensory, and autonomic functions below the lesion. Although functional electrical stimulation (FES) cycling rehabilitation can improve cardiopulmonary function, muscle mass, and locomotion, its clinical adoption is hindered by complex parameter tuning and a lack of standardized and personalized protocols.

Objective: The goal of this work is to first develop a methodology for the creation of FES patterns from electromyography (EMG), specifically from muscle synergy analysis. Then, to study how the obtained patterns compare to a standard one. We hypothesized that (1) the standard FES pattern would diverge from healthy muscle-activation timing, (2) it was designed for intermediate cadences, and (3) synergy-based patterns would yield smoother pedaling and better user ratings.

Methods: During data acquisition, we recorded EMG of eight leg muscles from eight healthy controls and two SCI patients while cycling at 30, 50, and 70 revolutions per minute (rpm) on a recumbent ergometer. Non-negative matrix factorization extracted muscle synergies and reconstructed EMG envelopes, which defined personalized stimulation ranges and amplitude profiles for each muscle. We quantified inter-limb symmetry and deviations of the personalized pattern from the standard one to characterize how each FES parameter set differed across trials. In the evaluation phase, eight healthy participants tested three patterns in random order for six minutes: the standard pattern, a fixed-50-rpm synergy-based pattern, and a synergy-based pattern adapting to the real-time cadence. Outcome measures were rpm variability and user perception ratings.

Results: Two of our three hypotheses were confirmed: (1) the standard FES pattern diverged significantly from healthy muscle-activation timing, and (2) it appeared to have been indeed designed for mid-range cadences (50 rpm approx.). However, the synergy-based personalization did not yield clear improvements over the standard pattern, and subjective preferences did not consistently align with objective metrics. Since the statistical tests yielded no significant difference between trials, two illustrative cases were shown, highlighting variability.

Conclusion: A practical workflow is recommended to first generate candidate patterns from muscle synergy analysis, conduct brief comparative trials using application-specific measures and user feedback, and then select the pattern that best balances these criteria for the intended rehabilitation protocol. ... Read more

Background Preterm birth is associated with an increased risk for neurodevelopmental impairments, requiring brain monitoring using amplitude-integrated electroencephalography (aEEG). While tools exist to detect severe brain dysfunction, methods for mild dysfunction—such as the Burdjalov scoring system or expert identification of sleep-wake cycles—are limited by subjectivity and require expert training. Existing automated sleep-staging models are typically trained on term neonates using polysomnography, a resource-intensive method not widely feasible in neonatal intensive care units (NICUs) for preterm neonates, where simplified aEEG with fewer electrodes is more commonly used.
Methods aEEG recordings from neurologically healthy neonates between 32 and 42 weeks postmenstrual age (PMA) were annotated for quiet sleep (QS) and non-quiet sleep (NQS) by a single expert clinician.
Results Five classifiers were trained to classify QS and NQS. A k-nearest neighbors model achieved a mean Cohen’s Kappa of 0.71± 0.12 in preterm infants, decreasing to 0.48 ± 0.21 in term infants. Features from QS segments were strongly correlated with PMA, enabling a PMA predictor model to achieve an average error of 0.88 weeks.
Conclusion Although performance on QS/NQS classification was strong for neonates between 33 and 37 weeks PMA, generalization across the full 32–42 week range remains challenging. Nevertheless, the low average error of the PMA predictor highlights its potential as a tool for detecting mild neuromaturation delays.
... Read more

Traditional surgical training is hampered by limited practice opportunities, arising from costly resources and restricted operating room access, and by the variable feedback of apprenticeship models, which challenges standardized skill acquisition. In this study, we evaluated the efficacy of a novel Augmented Reality (AR) application for drill-guide placement and investigated the effects of two contrasting learning frameworks: Productive Success (PS), which gradually increases the difficulty as the learner’s competence grow, and Productive Failure (PF), which intentionally introduces challenges early in training to promote deeper learning. We conducted a randomized controlled trial with 16 novice participants assigned to either learning framework (eight participants per each framework), completing both training and, after at least 24 hours, retention sessions. We assessed performance using Completion Time and Success Rate, alongside subjective measures of perceived workload (NASA-TLX) and user experience (UEQ). The results demonstrated that the AR application was highly effective at reducing Completion Time; both groups significantly reduced their Completion Time from their initial baseline to the retention session, and these skills were retained. However, a corresponding significant improvement in Success Rate was not observed within the study’s timeframe. Critically, we found no significant differences between the PS and PF groups at the retention session regarding final performance levels, perceived workload, or user experience. These findings contribute valuable evidence to the field of surgical education. Firstly, they validate the use of this AR application as an effective tool for rapidly building and retaining motor skills in novices. Secondly, they suggest that for this visuomotor task in an AR environment, the theoretical benefits of PF over PS did not manifest, with both strategies leading to comparable learning outcomes. This underscores the importance of investigating instructional designs specifically tailored to the unique context of AR-based motor training. Index Terms—Augmented Reality, Surgical Simulation, Productive Failure, Motor Learning, Instructional Design. ... Read more

Haptic technology focuses on the recreation of haptic information, i.e., a type of sensory input that uses tactile cues, forces, vibrations, or pressure to provide users with the sensation of touch, enabling users to interact physically with virtual or remote environments. One promising application of this technology lies in haptic training, where the possibility of using haptic feedback to facilitate or promote motor learning is studied. The focus of this paper lies on performance-enhancing haptic training methods, with a focus on designing a dynamic motor task. The objective of this paper is, therefore, to establish a preliminary framework that can be used to provide minimal haptic feedback while flying a quadcopter through a set of gates.
We focused on creating a preliminary framework that provides haptic feedback on the altitudinal axis of the quadcopter to the pilot using the control method Model Predictive Control (MPC). The haptic feedback is provided on the z-axis of a haptic Sigma.7 robot, which is also used as a remote controller to fly the quadcopter. The MPC implements the dynamical models of the quadcopter, and a haptic Sigma.7 robot, to determine the minimal force required to steer the Sigma.7 robot towards motor task completion. The system should provide minimal haptic force feedback within the proposed design requirements to prevent reliance on the assistance. We evaluated the effectiveness of our framework by evaluating its ability to control the quadcopter to the desired altitude setpoint under autonomous conditions using a haptic Sigma robot. Additionally, the design and performance of each of the individual building blocks of this framework, i.e. the quadcopter model, the haptic interface, and the MPC, were evaluated separately. The quadcopter, with the implementation of the onboard PID controllers, eliminating the steady-state errors and meeting the required settling times. The Sigma.7 model was sufficient within the established time horizon and range of operation, although shows limitations due to unmodelled frictional forces. The completed framework is capable of providing the Sigma.7 with the necessary input command to autonomously guide the quadcopter to its desired references in real-time, therefore completing its primary objective. Future work should explore improving the model components and integrating human elements into the predictive model. ... Read more

Recent research suggests that haptic feedback—the use of physical stimuli to simulate tactile experiences—plays a crucial role in simulations in virtual reality (VR), as it can enhance immersion and facilitate motor learning. Unlike real-world objects, virtual objects lack the property of mass, necessitating its simulation through haptic devices to convey a realistic sense of weight. However, rendering weight remains a challenge, particularly for ungrounded haptic devices, which maintain a free range of motion but often face limitations such as high latency, side effects through noise, vibrations, and airflow, or the need for expensive equipment. In this work, we present LeVR, a low-cost, portable haptic proxy that simulates weight by rendering the vertical forces experienced when lifting objects—within the system’s constraints—by leveraging the force generated by an accelerated mass. The system comprises a linear rail and a capstan drive mechanism and ncorporates an impedance-based control scheme. We characterized the system’s response through step and frequency analyses. Results show that LeVR can produce a force output within a latency of 2.5 ms and render forces at frequencies ranging from 1 to 11 Hz. Furthermore, we conducted a pilot user study in which participants sorted five virtual objects by weight, ranging from 17 g to 227 g, solely based on the stimuli produced by our prototype. The results indicate that participants could generally distinguish between different stimuli, though limitations such as force instability, oscillations, and fatigue affected sorting accuracy. With our proposed system we aim to contribute to research on weight perception, to ultimately increase the effectiveness of skill acquisition and motor learning in VR. ... Read more

This study investigates how deviations in avatar motion influence user motion in virtual reality (VR), specifically focusing on upper body and trunk motion in a virtual environment (VE). Previous research showed that user motion can be altered via the avatar follower effect, in which avatar deviations are followed by users. This is the first work exploring this effect for a deviation including the head. The primary objective was to explore whether these deviations could subconsciously guide user motions, potentially contributing to real-time motion sickness reduction in automated vehicles.
The experiment involved participants performing seated lateral leaning tasks where they were instructed to touch virtual goals with their heads. During some trials, the avatar unexpectedly deviated from the user's intended motion.
The results revealed that contrary to expectations, the avatar follower effect did not occur. Instead, an opposing effect was observed where participants' motions contradicted the avatar's deviations, particularly when the avatar stopped prior to the instructed goal. This effect was not influenced by the user's perspective (first or third person) or the scoring mechanism used in the game. However, individual personality traits, such as a tendency for autonomy or a focus on rewards, did affect the strength of the opposing effect.
These findings suggest that using avatar deviations to guide upper body and head motion in VR may not be effective, thus unsuited for applications such as motion sickness prevention in automated vehicles. ... Read more

Stroke survivors often struggle with gait asymmetry post-therapy. Researchers are exploring Virtual Reality (VR) to address this problem with the help of visual feedback and virtual avatars. VR also makes repetitive tasks more enjoyable, improving patient compliance and outcomes. Motor adaptation, essential in rehabilitation, involves adjusting movements to new conditions. Studies have used forms of motor adaptation with visual feedback to distort participants' gait symmetry, making people walk asymmetrically. This approach is called implicit Visual Feedback Distortion (VFD), where visual feedback is manipulated without the user's awareness. This thesis explores using implicit VFD with avatars in immersive VR to address gait asymmetry. An experiment with 11 healthy participants tested implicit VFD by gradually increasing the step length of the avatar's right leg. Contrary to previous screen-based VFD studies, results showed no significant effect on gait symmetry. Additionally, no correlations were found between step symmetry and psychological states (presence, embodiment, motivation). We hypothesize that the high distortion level on the right foot, suboptimal virtual environment design, and reported neck pain contributed to these findings. Future research should explore different VFD designs, or look at multiple groups to see what conditions lead to more gait asymmetry during adaptation. ... Read more

Rehabilitation following a stroke plays a crucial role in functional recovery and the regaining of independence. Advanced rehabilitation robots such as the Lokomat, C-mill, Rysen, and ZeroG have become integral tools for gait rehabilitation. The MATE (Minimally Actuated Tendon-based Exercise Environment) is a novel rehabilitation device that could offer a wider range of motion compared to the Lokomat while providing support for leg movement, unlike the C-Mill, Rysen, and ZeroG. However, initial testing on the MATE indicated that this passive tendon-based rehabilitation device lacks a proper connection to the wearer. Consequently, this study was conducted to design and evaluate an attachment model, ensuring that the pulling forces are comfortably transferred to the body and that the MATE fulfills its purpose of supporting and enhancing the natural gait. The study compared two user-centred attachment designs based on user experience, comfort, usability, acceptance, ability to follow the natural gait, and the difference in pulling forces on the legs. The findings revealed that the bandage design exerted greater control over the legs, while the cuff design provided more guidance. Additionally, it was observed that adhering to the user’s natural gait greatly influenced comfort and that walking with the MATE became easier with practice. Although the bandage design was preferred, the results suggest further iterations to enhance gait support, comfort, and usability. ... Read more

Moving through immersive virtual reality (VR) is commonly achieved by physically walking in the real room or using other techniques like an omnidirectional treadmill or walk-in-place. Roomscale walking is most similar to normal walking but is limited by physical space. However, other techniques can cause user experience issues such as VR sickness, balance problems, and feeling unnatural. Newer locomotion techniques are available such as powered VR shoes, which are shoes with motorized treadmills underneath. While walking, the shoes drive the user backward and actively negate the forward velocity, reducing the needed physical space. Yet, there is little evidence of the effect of powered VR shoes on user experience, which part of this work addresses. Additionally, previous research shows mismatched VR motion (optical flow) can increase VR sickness, cognitive load, and break presence. However, full-gait locomotion studies often focus on the device, neglecting optical flow, and what is the best body part to control optical flow direction is still an open question. Therefore, we first developed a novel algorithm to convert leg-based walking to optical flow while walking on VR shoes, which may also be used for other full-gait locomotion techniques. We conducted a study with 20 participants to find which of four optical flow implementations, differing in VR motion direction, resulted in the best user experience. These direction conditions were based on body-mounted trackers: i) head orientation, ii) hip orientation, iii) standing foot velocity direction, and iv) average orientation of both feet. Head-oriented walking resulted in a significantly worse user experience compared to other conditions, with no significant differences among any other conditions. Additionally, we found no effect of optical flow on VR sickness, Mental Effort, and Presence, contrary to previous studies, but instead significant differences in Ease of Use, Input responsiveness, and Appropriateness, and indication that other user experience factors might be impacted more. Finally, we discovered that walking on VR shoes, although not completely comfortable and natural, was learnable within 10 minutes for all participants under 60 years old. ... Read more

To offer engaging neurorehabilitation training to stroke patients, robotic exoskeletons have emerged as a beneficial tool to train motor tasks. However, in robotic therapy, the therapists are often limited in how they can interact with the patients. The training programs with exoskeletons are often standardized, not allowing the therapist to directly manipulate them and customize the training for specific patient needs. This paper presents a novel telerehabilitation system incorporating a therapist-in-the-loop haptic interface and immersive virtual reality (IVR), aimed at improving the interaction dynamics between patients and therapists during rehabilitation sessions. We conducted a human factors study involving 36 participants grouped in pairs, assigned as "Leaders" or "Followers," where the Leader had to guide the Follower (positioned in the exoskeleton) to a specific arm pose related to activities of daily living (ADL). This task was done under two conditions: demonstration and teleoperation. In the demonstration condition, the Follower could see the Leader displayed on a 2D screen in front of them showing them visually what was the correct pose whereas in the teleoperation condition, there was no visual aid but the Leader could guide the Follower using the haptic device. The study explored the efficiency, workload, and user experience of both modalities. Results indicated that teleoperation significantly reduced the time to complete tasks and facilitated more efficient and smoother movement patterns. While Leaders experienced reduced workload and increased motivation with the teleoperation condition, Followers reported less workload but also decreased motivation, suggesting a trade-off between task ease and engagement. In conclusion, the teleoperation system improves the ability for the therapist to interact with the exoskeleton but can disengage the patient. ... Read more

Introduction: Movement disorders, such as Cerebral Palsy, prevent children from fully developing their motor coordination abilities reducing their quality of life. Trunk control is a core coordination competency but there is limited variety in sitting based therapies. This paper investigates a theorised trunk support device for children which uses a system of elastic ropes and pulleys to support and prevent them from falling whilst they perform trunk control training exercises in a seated position. The aim of this study is to understand the mechanical properties required to ensure this device behaves safely and predictably. The device is considered safe if it prevents the child from falling and predictable if it always pulls the child towards an upright seating position. Additionally, it was investigated if the mechanical properties could be satisfied by off-the-shelf components and two possible pulley systems were compared.

Methods: To theoretically test if this device concept could meet the three criteria, a MATLAB simulation was written. A genetic optimization was then used to find the least stringent mechanical properties that still satisfy the three criteria. Off-the-shelf components that satisfy the mechanical properties were then found.

Results: Both pulley systems satisfied the safety and predictability criteria. Moreover, the necessary mechanical properties could be satisfied by off-the-shelf components, though some design modifications may be required. Ultimately, the configuration involving shorter ropes was determined to be the better option as it had less stringent mechanical requirements and potential design modifications would likely be easier to implement.

Conclusion: This study concluded that the optimised device, theoretically, shows good performance and seems practical to build. Future work is required to design a harness that would allow a child to comfortably train with the device. ... Read more

Immersive virtual reality (IVR) with head-mounted displays (HMDs) is expanding in various fields like training, but its effects on cognitive load from visual, auditory, and mental stimuli in virtual environments remain uncertain. This is particularly relevant in neurorehabilitation, where patients may suffer from training in overstimulating environments due to cognitive impairments. This study further explores how low and high levels of visual, auditory, and cognitive demands affect the cognitive load. Twenty-two participants used an HMD for a virtual shopping task, which involved selecting listed products and placing them in a cart, under baseline (the task without additional demands) and two stimulus complexity levels (low and high) for visual, auditory, and mental demands. The study assessed cognitive load using conventional (heart rate, variability, skin conductance, performance, self-reported questionnaire) and underexplored measures (head stillness, hand smoothness, gaze behavior), and explored behavior changes due to stimulus impact. Results showed that visual and auditory stimuli had minimal effects on cognitive load, with only specific measures showing any notable differences from the baseline. Mental stimuli significantly impacted cognitive load, with high mental tasks notably affecting the measures and behavior, whereas low mental tasks showed fewer changes. This research concluded that mental stimuli significantly increased the cognitive load in virtual environments, more than visual or auditory stimuli, suggesting future virtual reality designs should prioritize managing mental load. Furthermore, the study highlights the effectiveness of head stillness and gaze behavior as innovative measures for evaluating cognitive load. ... Read more

Lower-limb exoskeletons often use trajectory-tracking control to define the device's motion and assistance level. One challenge lies in ensuring a smooth and comfortable interaction between the user and the robotic device by defining a reference trajectory. While recent research has focused on generating individualized gait patterns based on user-specific body characteristics and walking speed, limited research has explored the subjective perception of these patterns and their impact on user experience and rehabilitation outcomes.

This study investigates user perceptions of individualized versus standard and random gait patterns, focusing on enjoyment, comfort, and naturalness. A predictive gait pattern model, incorporating individual data and walking speed, was developed and tested with human participants using a grounded robotic lower limb device. Participants compared the three gait pattern types and provided subjective feedback through a questionnaire.

Findings indicate no significant preference for any gait pattern in terms of enjoyment, comfort, and naturalness, except for physical strain where the predicted pattern caused significantly more strain than the standard. The analysis also revealed that longer engagement with the device led to increased comfort and naturalness, suggesting an adaptation effect. A general tendency towards preferring the standard pattern was noted, though further research is necessary to determine whether a larger sample size reveals significant differences. Additionally, the perception of different gait patterns and their effect on the rehabilitation outcome should be explored with stroke patients. ... Read more

Robotic rehabilitation systems that provide proprioceptive information offer a promising approach to helping stroke survivors regain lost proprioceptive functions. One potential way to provide proprioceptive information is viscosity rendering. However, how the modulated viscosity rendering affects brain activity remains unclear. To investigate the correlation between viscosity rendering and brain activity and to provide a neurological basis for the design of robotic rehabilitation systems, an experimental setup was developed to deliver various viscosity rendering and fixed stiffness rendering during hand movement. In the experiment, twelve healthy participants interacted with virtual bottles with the same bottle stiffness but filled with liquids of different viscosities under the same movement speed, providing different levels of proprioceptive information in the form of force on muscles and joints. Control conditions without viscosity and stiffness rendering were also tested, involving both passive and active hand movements at the same speed. Results showed that stronger mu-ERD and beta-ERD were observed during movements with viscosity and stiffness rendering compared to control conditions. No significant evidence suggested that different viscosity in rendering caused variations in mu-ERD or beta-ERD. Additionally, no significant differences were found between active movement without haptic rendering and passive movement in EEG activities. These findings suggest that while the existence of viscosity and stiffness rendering during movement strengthens brain activity, modulating viscosity rendering does not significantly affect this response. This insight is particularly valuable for designing robotic rehabilitation systems that incorporate viscosity rendering. ... Read more

While the presence and demand of robotic rehabilitation devices are rising, not many studies have been performed on haptic communication/ telerehabilitation with these devices. Despite therapists' desire to have the possibility to remain in the loop when their patients are performing exercises. This study aims to provide a telerehabilitation system that accommodates therapist-patient interaction during robotic rehabilitation and evaluate the system empirically on stability and transparency.
The system provides a platform for further research on telerehabilitation and haptic communication in robotic rehabilitation. Working towards a system that allows the therapist, when desired, to intuitively interact with the patient while they are performing rehabilitation exercises using a robotic device. A modular telerehabilitation system is designed using the ARMin V (ETH Zurich) upper extremity exoskeleton as the patient side, and the haptic end-effector device Sigma.7 (Force Dimensions) as the therapist's side. A visualization is provided to the therapist side using Unity and additional features are added to improve usability. The telerehabilitation system is bilateral impedance controlled through a proportional-derivative controller.
An experiment is performed in which the observing participant is asked to resist motion (analyze stability) or to be compliant with the motion (analyze transparency).
The empirical analysis showed promising first results on position tracking, effective communication of haptic cues, stability, and transparency.
However, UDP communication rate could be raised, and the scaling of force and workspace between Sigma.7 and ARMin V could be better matched to improve transparency. ... Read more

Robots can aid in post-stroke motor function recovery and motor learning through the use of haptic feedback during collaborative training. A clear objective in robotic-assisted motor learning is to adapt the haptic feedback to individual users, but personal characteristics are not yet considered in this adaptation.

We investigated the suitability of a haptic guidance feedback strategy, based on participants’ locus of control character trait, compared to training without haptic guidance. For this purpose, a motor learning experiment was conducted on 42 healthy participants, where the internal dynamics of a pendulum had to be learned in order to hit upcoming targets. For two groups, training either with or without haptic guidance, we assessed motor learning and its generalization to similar tasks through target hitting performance, as well as behavior during training and perceived user experience.

Evidence was found of a relatively better performance improvement in both training and long-term (generalization of) motor learning for participants with a more internal compared to external locus of control. Lower observed interaction force during training and increasingly better performance throughout training
in these participants may have caused these motor learning differences. More positive user experience in these individuals through a higher perceived control over the pendulum and lower perceived frustration with haptic guidance may have also contributed.

Combined, this suggests an intrinsically better compatibility
with haptic guidance for people with a more internal rather than
external locus of control, for motor learning, during training and
in user experience ... Read more

People that are recovering from a stroke need frequent and high-intensity training to regain their upper-limb capacity. This will eventually result in better performances and higher quality of their daily life. Robotic devices are often used to assist stroke patients in rehabilitation. The minimally-supervised portable hand trainer, which is currently developed at the Motor Learning and Neurorehabilitation Lab of the TU Delft, specifically focuses on hand and forearm rehabilitation. Haptic feedback is used in a virtual game to train patients' finger flexion and extension and forearm pronosupination.
Prior to this master thesis, a feasibility and usability study has been performed with the second iteration of the hand trainer in collaboration with therapists from Rijndam and healthy participants, showing room for improvement.

In this graduation project, the portable hand trainer is redesigned to develop an improved product design in comparison to the second iteration. Following a human-centered design approach, a modified version of the double diamond method was created to achieve a redesign that enables more functional, ergonomic, and motivating rehabilitation training.

Analysis on strokes, on rehabilitation, on the state-of-the-art, through peer tests, and on the usability study, were performed to create a decision matrix to define a list of potential improvements, distinguishing high-priority, medium-priority and low-priority improvements.
The high-priority improvements have been thoroughly addressed in multiple cycles of ideation-, developing- and validating activities. The results are combined and transformed into a hardware-ready 3D prototype that demonstrates improvement in the pronosupination movement, the donning and doffing of the device and the wrist support. The prototype of the third iteration of the portable hand trainer is evaluated through interviews with experts in the field to reflect on the project goal and propose recommendations on future work.
The medium-priority improvements have been addressed in one cycle of ideation activities of which the results are presented in sketches to advice on further development.
The low-priority improvements have not been addressed in this project. ... Read more

Virtual training environments are powerful tools for various applications. To increase the immersion and realism of these environments, several devices have been developed capable of rendering a wide range of haptic sensations. As humans mainly interact with objects using their hands, the main focus of research has been on developing devices capable of providing feedback to the hand and fingers. Currently, most of these devices only provide one form of feedback, either kinesthetic feedback to finger posture or tactile sensations in the form of pressing or skin stretching. These devices seldom provide more than one kind of feedback while remaining compact enough to be wearable with a natural range of motion of the hand. In this work, we present a device that combines an existing kinesthetic feedback glove with a novel tactile fingertip display. The haptic display consists of a cable-driven platform, powered by a stand-alone actuation module. It has been designed to be compact enough for a near-natural range of motion, with the possibility of multi-finger applications in mind. To validate the design, we conducted an experiment with 16 healthy young par- ticipants who were asked to reproduce virtual shapes with their index fingers after exploring those shapes under two different conditions: 1) with purely kinesthetic feedback, and 2) with kinesthetic feedback and tactile feedback. The outcome metrics were the exploration time, reproduction time, and reproduction error. For each testing condition, the workload and motivation of the participants were also evaluated. We found that participants had a lower reproduction error and used more time to reproduce the shapes with the novel haptic display enabled compared to purely kinesthetic feedback. We did not find significant differences in exploration time, workload, or motivation between testing conditions. Thus, the combined feedback provided by our novel device leads to better performance in shape reproduction compared to only kinesthetic feedback. Further, our device is lightweight and compact, potentially enabling multi-finger use which may lead to even greater performance and immersion in virtual object manipulation tasks. ... Read more