Hand Orthosis Research Articles

2190 Longitudinal changes in EEG power envelope connectivity are proportional to motor recovery in chronic stroke patients

OBJECTIVES/SPECIFIC AIMS: The objective of this study is to determine the degree to which the use of a contralesionally-controlled brain-computer interface for stroke rehabilitation drives change in interhemispheric motor cortical activity. METHODS/STUDY POPULATION: Ten chronic stroke patients were trained in the use of a brain-computer interface device for stroke recovery. Patients perform motor imagery to control the opening and closing of a motorized hand orthosis. This device was sent home with patients for 12 weeks, and patients were asked to use the device 1 hour per day, 5 days per week. The Action Research Arm Test (ARAT) was performed at 2-week intervals to assess motor function improvement. Before the active motor imagery task, patients were asked to quietly rest for 90 seconds before the task to calibrate recording equipment. EEG signals were acquired from 2 electrodes—one each centered over left and right primary motor cortex. Signals were preprocessed with a 60 Hz notch filter for environmental noise and referenced to the common average. Power envelopes for 1 Hz frequency bands (1–30 Hz) were calculated through Gabor wavelet convolution. Correlations between electrodes were then calculated for each frequency envelope on the first and last 5 runs, thus generating one correlation value per subject, per run. The chosen runs approximately correspond to the first and last week of device usage. These correlations were Fisher Z-transformed for comparison. The first and last 5 run correlations were averaged separately to estimate baseline and final correlation values. A difference was then calculated between these averages to determine correlation change for each frequency. The relationship between beta-band correlation changes (13–30 Hz) and the change in ARAT score was determined by calculating a Pearson correlation. RESULTS/ANTICIPATED RESULTS: Beta-band inter-electrode correlations tended to decrease more in patients achieving greater motor recovery (Pearson’s r=−0.68, p=0.031). A similar but less dramatic effect was observed with alpha-band (8–12 Hz) correlation changes (Pearson’s r=−0.42, p=0.22). DISCUSSION/SIGNIFICANCE OF IMPACT: The negative correlation between inter-electrode power envelope correlations in the beta frequency band and motor recovery indicates that activity in the motor cortex on each hemisphere may become more independent during recovery. The role of the unaffected hemisphere in stroke recovery is currently under debate; there is conflicting evidence regarding whether it supports or inhibits the lesioned hemisphere. These findings may support the notion of interhemispheric inhibition, as we observe less in common between activity in the 2 hemispheres in patients successfully achieving recovery. Future neuroimaging studies with greater spatial resolution than available with EEG will shed further light on changes in interhemispheric communication that occur during stroke rehabilitation.

Pilot Study Combining Electrical Stimulation and a Dynamic Hand Orthosis for Functional Recovery in Chronic Stroke.

We investigated the effect of a combined neuromuscular electrical stimulation (ES) and dynamic hand orthosis (DHO) regimen with a group of people with chronic stroke to improve performance on specific daily tasks. Four people with chronic stroke participated in an ES-DHO regimen using the affected upper extremity 5×/wk for 6 wk. Outcome measures included grip strength, range of motion (ROM), and analysis of muscle activation-deactivation during release of grasp through electromyography. Ability to perform specific daily living tasks was assessed using the Assessment of Motor and Process Skills (AMPS). Results suggested that improvements in strength, ROM, and grasp deactivation are possible with the combined ES-DHO regimen. All participants' AMPS motor scores improved. An ES-DHO regimen may improve motor skills needed for functional task performance in people with chronic stroke. Results should be interpreted cautiously because of the pilot nature of the study and the small sample size.

Evaluation of a functional hand orthosis combined with electrical stimulation adjunct to arm-hand rehabilitation in subacute stroke patients with a severely to moderately affected hand function

Purpose: To investigate the usability and effectiveness of a functional hand orthosis, combined with electrical stimulation adjunct to therapy-as-usual, on functional use of the moderately/severely impaired hand in sub-acute stroke patients.Materials and Methods: Single case experiment (A-B-A′-design) involving eight sub-acute stroke patients. The functional hand orthosis and electrical stimulation were used for six weeks, four days/week, 45′/day. Outcome measures: Action_Research_Arm_Test, Intrinsic_Motivation_Inventory.Results: At group level, patients improved 19.2 points (median value) (interquartile range: [8.8, 29.5] points) on the Action_Research_Arm_Test (p = 0.001). After correcting for spontaneous recovery and/or therapy-as-usual effects Action_Research_Arm_Test scores still improved significantly (median: 17.2 points; interquartile range: [5.1, 29.2] points) (p = 0.002). At individual level, six patients had improved as to arm-hand skill performance at follow-up (p < = 0.010). In one patient, arm-hand skill performance improvement did not attain statistical significance. In another patient, no arm-hand skill performance improvement was observed. Average Intrinsic_Motivation_Inventory sub-scores were between 4.6 and 6.3 (maximum: 7), except for ‘perceived pressure/tension’ (3.3).Conclusion: Sub-acute stroke patients who display only little/modest improvement on their capacity to perform daily activities, seem to benefit from training with a dynamic arm orthosis in combination with electrical stimulation. Patients’ perceived intrinsic motivation and sense of self-regulation was high.Implications for rehabilitationArm-hand training featuring the dynamic hand orthosis in combination with electrical stimulation shows a shift from no dexterity to dexterity.As to the users’ experience regarding the dynamic hand orthosis, patients perceive a high-intrinsic motivation and sense of self-regulation.Combining the orthosis with electrical stimulation creates opportunities for a nonfunctional hand towards task-oriented training.

The necessity of using high quality orthoses in rehabilitation medicine

In rehabilitation medicine there is increasing need of using high quality orthoses that can provide either good stability of the joint or good correction of the postural defect. The advantages of using orthoses that are in the same time hypoallergenic, lightweight, flexible, resistant and durable over time should be considered when prescribing them in clinical practice. This study presents different types of orthoses and the necessity of proper selection of materials when choosing the best ones. We included 34 patients diagnosed with different musculoskeletal conditions (thoracic and thoraco-lumbar scoliosis, genu valgum deviation and rheumatoid arthritis) that required the use of special orthoses (thoraco-lumbar braces, knee or hand orthoses). Patients were asked to complete a questionnaire regarding the quality of the orthoses that they have been used. The following characteristics of an orthosis should be considered when choosing the right one: easily wearable, comfortable, offering good stability of a joint, high quality, lightweight, hypoallergenic and resistant.

Motor Imagery-Based Brain-Computer Interface Coupled to a Robotic Hand Orthosis Aimed for Neurorehabilitation of Stroke Patients.

Motor imagery-based brain-computer interfaces (BCI) have shown potential for the rehabilitation of stroke patients; however, low performance has restricted their application in clinical environments. Therefore, this work presents the implementation of a BCI system, coupled to a robotic hand orthosis and driven by hand motor imagery of healthy subjects and the paralysed hand of stroke patients. A novel processing stage was designed using a bank of temporal filters, the common spatial pattern algorithm for feature extraction and particle swarm optimisation for feature selection. Offline tests were performed for testing the proposed processing stage, and results were compared with those computed with common spatial patterns. Afterwards, online tests with healthy subjects were performed in which the orthosis was activated by the system. Stroke patients' average performance was 74.1 ± 11%. For 4 out of 6 patients, the proposed method showed a statistically significant higher performance than the common spatial pattern method. Healthy subjects' average offline and online performances were of 76.2 ± 7.6% and 70 ± 6.7, respectively. For 3 out of 8 healthy subjects, the proposed method showed a statistically significant higher performance than the common spatial pattern method. System's performance showed that it has a potential to be used for hand rehabilitation of stroke patients.

IGrab: hand orthosis powered by twisted and coiled polymer muscles

Several works have been reported in powered hand orthosis in the last ten years for assistive or rehabilitative purposes. However, most of these approaches uses conventional actuators such as servo motors to power orthosis. In this work, we demonstrate the recently reported twisted and coiled polymeric (TCP) muscles to drive a compact, light, inexpensive and wearable upper extremity device, iGrab. A 3D printed orthotic hand module was designed, developed and tested for the performance. The device has six 2-ply muscles of diameter 1.35 mm with a length of 380 mm. We used a single 2-ply muscle for each finger and two 2-ply muscles for the thumb. Pulsed actuation of the muscles at 1.8 A current for 25 s with 7% duty cycle under natural cooling showed full flexion of the fingers within 2 s. Modeling and simulation were performed on the device using standard Euler–Lagrangian equations. Our artificial muscles powered hand orthosis demonstrated the capability of pinching and picking objects of different shapes, weights, and sizes.

Mesh three-dimensional arm orthosis with built-in ultrasound physiotherapy system

The possibility of using the built-in ultrasound physiotherapy system of the hand orthosis is explored in the work. The individual mesh orthosis from nylon 12 was manufactured by the 3D prototyping method on the installation of selective laser sintering SLS SPro 60HD. The applied technology of three-dimensional scanning made it possible to obtain a model of the patient’s hand and on the basis of it to build a virtual model of the mesh frame. In the course of the research, the developed system of ultrasound exposure was installed on the orthosis and its tests were carried out. As a result, the acceleration of the healing process and the reduction in the time of wearing orthosis were found.

Single DoF Hand Orthosis for Rehabilitation of Stroke and SCI Patients

Many stroke and spinal cord injury patients suffer from paralysis which range from severe to nominal. Some of them, after therapy, could regain most of the motor control, particularly in hands if the severity level is not so high. In this paper we propose a hand orthosis for such patients whose stroke and spinal cord injury severity is nominal and the motor control in hands can be regained by therapy as part of their rehabilitation process. The patients can wear this orthosis and the therapy can be done with simple Human Computer Interface. The physicians, the physiotherapists and the patients themselves can carry out the therapy with the help of this device. The tests conducted in the lab and the results obtained are very promising that this can be an effective mechanism for stroke and spinal cord injury patients in their rehabilitation process. The hand orthosis is designed and fabricated locally so that it can be made available to such patients at an affordable cost.

Exploratory design of a compliant mechanism for a dynamic hand orthosis: Lessons learned.

This study does not describe a success-story. Instead, it describes an exploratory process and the lessons learned while designing a compliant mechanism for a dynamic hand orthosis. Tools from engineering optimization and rapid prototyping techniques were used, with the goal to design a mechanism to compensate for hypertonic or contracted finger muscles. Results show that the mechanism did not reach its design constraints, mostly because it could not provide for the necessary stiffness and compliance at the same time. Hence, the presented approach is more suited for design problems with either lower forces or less displacement. It was concluded that physiological stiffness models are an important part when modeling hand orthoses. Moreover, further research on compliant mechanisms in dynamic hand orthoses should focus on the feasibility of implementing more complex three-dimensional shapes, i.e., compliant shell mechanisms.

EMG pattern classification to control a hand orthosis for functional grasp assistance after stroke.

Wearable orthoses can function both as assistive devices, which allow the user to live independently, and as rehabilitation devices, which allow the user to regain use of an impaired limb. To be fully wearable, such devices must have intuitive controls, and to improve quality of life, the device should enable the user to perform Activities of Daily Living. In this context, we explore the feasibility of using electromyography (EMG) signals to control a wearable exotendon device to enable pick and place tasks. We use an easy to don, commodity forearm EMG band with 8 sensors to create an EMG pattern classification control for an exotendon device. With this control, we are able to detect a user's intent to open, and can thus enable extension and pick and place tasks. In experiments with stroke survivors, we explore the accuracy of this control in both non-functional and functional tasks. Our results support the feasibility of developing wearable devices with intuitive controls which provide a functional context for rehabilitation.

Fully embedded myoelectric control for a wearable robotic hand orthosis.

To prevent learned non-use of the affected hand in chronic stroke survivors, rehabilitative training should be continued after discharge from the hospital. Robotic hand orthoses are a promising approach for home rehabilitation. When combined with intuitive control based on electromyography, the therapy outcome can be improved. However, such systems often require extensive cabling, experience in electrode placement and connection to external computers. This paper presents the framework for a stand-alone, fully wearable and real-time myoelectric intention detection system based on the Myo armband. The hard and software for real-time gesture classification were developed and combined with a routine to train and customize the classifier, leading to a unique ease of use. The system including training of the classifier can be set up within less than one minute. Results demonstrated that: (1) the proposed algorithm can classify five gestures with an accuracy of 98%, (2) the final system can online classify three gestures with an accuracy of 94.3% and, in a preliminary test, (3) classify three gestures from data acquired from mildly to severely impaired stroke survivors with an accuracy of over 78.8%. These results highlight the potential of the presented system for electromyography-based intention detection for stroke survivors and, with the integration of the system into a robotic hand orthosis, the potential for a wearable platform for all day robot-assisted home rehabilitation.

A multichannel-near-infrared-spectroscopy-triggered robotic hand rehabilitation system for stroke patients.

There is a demand for a new neurorehabilitation modality with a brain-computer interface for stroke patients with insufficient or no remaining hand motor function. We previously developed a robotic hand rehabilitation system triggered by multichannel near-infrared spectroscopy (NIRS) to address this demand. In a preliminary prototype system, a robotic hand orthosis, providing one degree-of-freedom motion for a hand's closing and opening, is triggered by a wireless command from a NIRS system, capturing a subject's motor cortex activation. To examine the feasibility of the prototype, we conducted a preliminary test involving six neurologically intact participants. The test comprised a series of evaluations for two aspects of neurorehabilitation training in a real-time manner: classification accuracy and execution time. The effects of classification-related factors, namely the algorithm, signal type, and number of NIRS channels, were investigated. In the comparison of algorithms, linear discrimination analysis performed better than the support vector machine in terms of both accuracy and training time. The oxyhemoglobin versus deoxyhemoglobin comparison revealed that the two concentrations almost equally contribute to the hand motion estimation. The relationship between the number of NIRS channels and accuracy indicated that a certain number of channels are needed and suggested a need for a method of selecting informative channels. The computation time of 5.84 ms was acceptable for our purpose. Overall, the preliminary prototype showed sufficient feasibility for further development and clinical testing with stroke patients.

Methodologies for determining minimal grasping requirements and sensor locations for sEMG-based assistive hand orthosis for SCI patients.

In this paper, we address two of the most important challenges in development and control of assistive hand orthosis. First, supported by experimental results, we present a method to determine an optimal set of grasping poses, essential for grasping daily objects. Second, we present a method for determining the minimal number of surface EMG sensors and their locations to carry out EMG-based intention recognition and to control the assistive device by differentiating between the hand poses.

SCRIPT passive orthosis: design of interactive hand and wrist exoskeleton for rehabilitation at home after stroke

Recovery of functional hand movements after stroke is directly linked to rehabilitation duration and intensity. Continued therapy at home has the potential to increase both. For many patients this requires a device that helps them overcome the hyperflexion of wrist and fingers that is limiting their ability to open and use their hand. We developed an interactive hand and wrist orthosis for post-stroke rehabilitation that provides compliant and adaptable extension assistance at the wrist and fingers, interfaces with motivational games based on activities of daily living, is integrated with an off-the-shelf mobile arm support and includes novel wrist and finger actuation mechanisms. During the iterative development, multiple prototypes have been evaluated by therapists in clinical settings and used intensively and independently by 33 patients at home. This paper details the final design of the SCRIPT passive orthosis resulting from these efforts.

Effects of training with a passive hand orthosis and games at home in chronic stroke: a pilot randomised controlled trial

Objectives: To compare user acceptance and arm and hand function changes after technology-supported training at home with conventional exercises in chronic stroke. Secondly, to investigate the relation between training duration and clinical changes. Design: A randomised controlled trial. Setting: Training at home, evaluation at research institute. Subjects: Twenty chronic stroke patients with severely to mildly impaired arm and hand function. Interventions: Participants were randomly assigned to six weeks (30 minutes per day, six days a week) of self-administered home-based arm and hand training using either a passive dynamic wrist and hand orthosis combined with computerised gaming exercises (experimental group) or prescribed conventional exercises from an exercise book (control group). Main measures: Main outcome measures are the training duration for user acceptance and the Action Research Arm Test for arm and hand function. Secondary outcomes are the Intrinsic Motivation Inventory, Fugl-Meyer assessment, Motor Activity Log, Stroke Impact Scale and grip strength. Results: The control group reported a higher training duration (189 versus 118 minutes per week, P = 0.025). Perceived motivation was positive and equal between groups (P = 0.935). No differences in clinical outcomes over training between groups were found (P ⩾ 0.165). Changes in Box and Block Test correlated positively with training duration (P = 0.001). Conclusions: Both interventions were accepted. An additional benefit of technology-supported arm and hand training over conventional arm and hand exercises at home was not demonstrated. Training duration in itself is a major contributor to arm and hand function improvements.

A Critical Analysis of a Hand Orthosis Reverse Engineering and 3D Printing Process.

The possibility to realize highly customized orthoses is receiving boost thanks to the widespread diffusion of low-cost 3D printing technologies. However, rapid prototyping (RP) with 3D printers is only the final stage of patient personalized orthotics processes. A reverse engineering (RE) process is in fact essential before RP, to digitize the 3D anatomy of interest and to process the obtained surface with suitable modeling software, in order to produce the virtual solid model of the orthosis to be printed. In this paper, we focus on the specific and demanding case of the customized production of hand orthosis. We design and test the essential steps of the entire production process with particular emphasis on the accurate acquisition of the forearm geometry and on the subsequent production of a printable model of the orthosis. The choice of the various hardware and software tools (3D scanner, modeling software, and FDM printer) is aimed at the mitigation of the design and production costs while guaranteeing suitable levels of data accuracy, process efficiency, and design versatility. Eventually, the proposed method is critically analyzed so that the residual issues and critical aspects are highlighted in order to discuss possible alternative approaches and to derive insightful observations that could guide future research activities.

Study of Effectiveness of Shoulder Elbow Wrist Hand Orthosis in the Management of Glenohumeral Subluxation in Post-stroke Hemiplegic Patients

Abstract Objective Study of effectiveness of shoulder elbow wrist hand orthosis in the management of glenohumeral subluxation in post-stroke hemiplegic patients. Methods Design: Randomised control trial. Setting Department of Physical Medicine and Rehabilitation, Regional Institute of Medical Sciences (RIMS), Imphal. Participants Post-stroke hemiplegic patients (n=120) having glenohumeral subluxation (GHS) as confirmed by x-ray. Duration One and half years (August 2010 to January 2012). Intervention Control group (n=60) received routine rehabilitation programme for hemiplegic practice in the Department of PMR, RIMS while the experiment group (n=60) received shoulder elbow wrist hand orthosis in addition to rehabilitation programme. Outcomes Grade of glenohumeral subluxation using x-ray. Results Experiment group showed reduction in the glenohumeral subluxation which is statistically significant when compared to control group (p&lt;0.001). Conclusions Use of upper limb orthosis in addition to routine rehabilitation programme can effectively reduce glenohumeral subluxation in post-stroke hemiplegic patients.

Feasibility study into self-administered training at home using an arm and hand device with motivational gaming environment in chronic stroke.

BackgroundAssistive and robotic training devices are increasingly used for rehabilitation of the hemiparetic arm after stroke, although applications for the wrist and hand are trailing behind. Furthermore, applying a training device in domestic settings may enable an increased training dose of functional arm and hand training. The objective of this study was to assess the feasibility and potential clinical changes associated with a technology-supported arm and hand training system at home for patients with chronic stroke.MethodsA dynamic wrist and hand orthosis was combined with a remotely monitored user interface with motivational gaming environment for self-administered training at home. Twenty-four chronic stroke patients with impaired arm/hand function were recruited to use the training system at home for six weeks. Evaluation of feasibility involved training duration, usability and motivation. Clinical outcomes on arm/hand function, activity and participation were assessed before and after six weeks of training and at two-month follow-up.ResultsMean System Usability Scale score was 69 % (SD 17 %), mean Intrinsic Motivation Inventory score was 5.2 (SD 0.9) points, and mean training duration per week was 105 (SD 66) minutes. Median Fugl-Meyer score improved from 37 (IQR 30) pre-training to 41 (IQR 32) post-training and was sustained at two-month follow-up (40 (IQR 32)). The Stroke Impact Scale improved from 56.3 (SD 13.2) pre-training to 60.0 (SD 13.9) post-training, with a trend at follow-up (59.8 (SD 15.2)). No significant improvements were found on the Action Research Arm Test and Motor Activity Log.ConclusionsRemotely monitored post-stroke training at home applying gaming exercises while physically supporting the wrist and hand showed to be feasible: participants were able and motivated to use the training system independently at home. Usability shows potential, although several usability issues need further attention. Upper extremity function and quality of life improved after training, although dexterity did not. These findings indicate that home-based arm and hand training with physical support from a dynamic orthosis is a feasible tool to enable self-administered practice at home. Such an approach enables practice without dependence on therapist availability, allowing an increase in training dose with respect to treatment in supervised settings.Trial registrationThis study has been registered at the Netherlands Trial Registry (NTR): NTR3669.

Design and performance characterization of a hand orthosis prototype to aid activities of daily living in a post-stroke population.

This paper presents the design of a hand orthosis prototype intended to assist persons with hand paresis, as a result of stroke, perform activities of daily living. Among its attributes, the orthosis is characterized by a low mass and small profile, while still offering the power assistance of a robotic exoskeleton. Experimental characterization of the orthosis is presented, including its mass, envelope dimensions, motion bandwidth, and joint torque characteristics.

Performance Assessment of a Brain–Computer Interface Driven Hand Orthosis

Stroke survivors are typically affected by hand motor impairment. Despite intensive rehabilitation and spontaneous recovery, improvements typically plateau a year after a stroke. Therefore, novel approaches capable of restoring or augmenting lost motor behaviors are needed. Brain-computer interfaces (BCIs) may offer one such approach by using neurophysiological activity underlying hand movements to control an upper extremity orthosis. To test the performance of such a system, we developed an electroencephalogram-based BCI controlled electrically actuated hand orthosis. Six able-bodied participants voluntarily grasped/relaxed one hand to elicit BCI-mediated closing/opening of the orthosis mounted on the opposite hand. Following a short training/calibration procedure, participants demonstrated real-time, online control of the orthosis by following computer cues. Their performances resulted in an average of 1.15 (standard deviation: 0.85) false alarms and 0.22 (0.36) omissions per minute. Analysis of signals from electrogoniometers mounted on both hands revealed an average correlation between voluntary and BCI-mediated movements of 0.58 (0.13), with all but one online performance being statistically significant. This suggests that a BCI driven hand orthosis is feasible, and therefore should be tested in stroke individuals with hand weakness. If proven viable, this technology may provide a novel approach to the neuro-rehabilitation of hand function after stroke.