Instrumented Glove Research Articles

Retraining and assessing hand movement after stroke using the MusicGlove: comparison with conventional hand therapy and isometric grip training.

BackgroundIt is thought that therapy should be functional, be highly repetitive, and promote afferent input to best stimulate hand motor recovery after stroke, yet patients struggle to access such therapy. We developed the MusicGlove, an instrumented glove that requires the user to practice gripping-like movements and thumb-finger opposition to play a highly engaging, music-based, video game. The purpose of this study was to 1) compare the effect of training with MusicGlove to conventional hand therapy 2) determine if MusicGlove training was more effective than a matched form of isometric hand movement training; and 3) determine if MusicGlove game scores predict clinical outcomes.Methods12 chronic stroke survivors with moderate hemiparesis were randomly assigned to receive MusicGlove, isometric, and conventional hand therapy in a within-subjects design. Each subject participated in six one-hour treatment sessions three times per week for two weeks, for each training type, for a total of 18 treatment sessions. A blinded rater assessed hand impairment before and after each training type and at one-month follow-up including the Box and Blocks (B & B) test as the primary outcome measure. Subjects also completed the Intrinsic Motivation Inventory (IMI).ResultsSubjects improved hand function related to grasping small objects more after MusicGlove compared to conventional training, as measured by the B & B score (improvement of 3.21±3.82 vs. -0.29±2.27 blocks; P=0.010) and the 9 Hole Peg test (improvement of 2.14±2.98 vs. -0.85±1.29 pegs/minute; P=0.005). There was no significant difference between training types in the broader assessment batteries of hand function. Subjects benefited less from isometric therapy than MusicGlove training, but the difference was not significant (P>0.09). Subjects sustained improvements in hand function at a one month follow-up, and found the MusicGlove more motivating than the other two therapies, as measured by the IMI. MusicGlove games scores correlated strongly with the B & B score.ConclusionsThese results support the hypothesis that hand therapy that is engaging, incorporates high numbers of repetitions of gripping and thumb-finger opposition movements, and promotes afferent input is a promising approach to improving an individual’s ability to manipulate small objects. The MusicGlove provides a simple way to access such therapy.

Wrist biomechanics during snowboard falls

Wrist injuries during snowboarding are very common. An instrumented snowboarding glove was developed to measure flexion/extension of the wrist in the sagittal plane, as well as forces and moments at the hand and wrist joint during snowboarding. On-slope data were analyzed from 128 falls resulting in hand impacts for 20 snowboarders. Impact forces and wrist extension moments varied widely by age, experience level, and fall direction. Backward falls resulted in significantly higher maximum force than forward falls ( p = 0.038). Adults had significantly higher maximum force ( p = 0.026) and maximum extension moments compared to young adults ( p = 0.049). Beginners suffered more impacts that resulted in higher maximum loads generated and wrist angles that did not reach terminal extension. A significant percentage of all falls resulted in wrist extension near terminal extension. This study provides novel hand and wrist biomechanical data in snowboarding falls that can be used to guide the development of wrist protector standards and products.

Microstimulation Activates a Handful of Muscle Synergies

Muscle synergies have been proposed as a mechanism to simplify movement control. Whether these coactivation patterns have any physiological reality within the nervous system remains unknown. Here we applied electrical microstimulation to motor cortical areas of rhesus macaques to evoke hand movements. Movements tended to converge toward particular postures, driven by synchronous bursts of muscle activity. Across stimulation sites, the muscle activations were reducible to linear sums of a few basic patterns-each corresponding to a muscle synergy evident in voluntary reach, grasp, and transport movements made by the animal. These synergies were represented nonuniformly over the cortical surface. We argue that the brain exploits these properties of synergies-postural equivalence, low dimensionality, and topographical representation-to simplify motor planning, even for complex hand movements.

Finger Tendon Travel Associated with Sequential Trigger Nail Gun Use

OCCUPATIONAL APPLICATIONS This article reports a method for assessing finger tendon motion associated with the use of a sequential actuation trigger pneumatic nail gun. The two-stage actuation process of the sequential actuation trigger reduces risk of nail puncture injury from unintended nail discharge (relative to the higher risk of the contact actuation trigger). However, widespread adoption of the sequential actuation trigger nail gun throughout the construction industry has been hindered by beliefs about productivity and musculoskeletal concerns about the repetitive trigger actuation and finger motion for each nail fired. Though existing guidelines for finger tendon travel exposure are not well established, predictions derived with the present method combined with productivity standards suggest insufficient evidence to contradict the safety-based recommendation to adopt the sequential actuation trigger trigger. TECHNICAL ABSTRACT Background: Pneumatic nail guns used in wood framing are equipped with one of two triggering mechanisms. Sequential actuation triggers have been shown to be a safer alternative to contact actuation triggers because they reduce traumatic injury risk. However, the sequential actuation trigger must be depressed for each individual nail fired as opposed to the contact actuation trigger, which allows the trigger to be held depressed as nails are fired repeatedly by bumping the safety tip against the workpiece. As such, concerns have been raised about risks for cumulative trauma injury, and reduced productivity, due to repetitive finger motion with the sequential actuation trigger. Purpose: This study developed a method to predict cumulative finger flexor tendon travel associated with the sequential actuation trigger nail gun from finger joint kinematics measured in the trigger actuation and productivity standards for wood-frame construction tasks. Methods: Finger motions were measured from six users wearing an instrumented electrogoniometer glove in a simulation of two common framing tasks—wall building and flat nailing of material. Flexor tendon travel was calculated from the ensemble average kinematics for an individual nail fired. Results: Finger flexor tendon travel was attributable mostly to proximal interphalangeal and distal interphalangeal joint motion. Tendon travel per nail fired appeared to be slightly greater for a wall-building task than a flat nailing task. The present study data, in combination with construction industry productivity standards, suggest that a high-production workday would be associated with less than 60 m/day cumulative tendon travel per worker (based on 1700 trigger presses/day). Conclusion and Applications: These results suggest that exposure to finger tendon travel from sequential actuation trigger nail gun use may be below levels that have been previously associated with high musculoskeletal disorder risk.

Design and evaluation of a low-cost instrumented glove for hand function assessment

BackgroundThe evaluation of hand function impairment following a neurological disorder (stroke and cervical spinal cord injury) requires sensitive, reliable and clinically meaningful assessment tools. Clinical performance measures of hand function mainly focus on the accomplishment of activities of daily living (ADL), typically rather complex tasks assessed by a gross ordinal rating; while the motor performance (i.e. kinematics) is less detailed. The goal of this study was to develop a low-cost instrumented glove to capture details in grasping, feasible for the assessment of hand function in clinical practice and rehabilitation settings.MethodsDifferent sensor types were tested for output signal stability over time by measuring the signal drift of their step responses. A system that converted sensor output voltages into angles based on pre-measured curves was implemented. Furthermore, the voltage supply of each sensor signal conditioning circuit was increased to enhance the sensor resolution. The repeatability of finger bending trajectories, recorded during the performance of three ADL-based tasks, was established using the intraclass correlation coefficient (ICC). Moreover, the accuracy of the glove was evaluated by determining the agreement between angles measured with the embedded sensors and angles measured by traditional goniometry. In addition, the feasibility of the glove was tested in four patients with a pathological hand function caused by a cervical spinal cord injury (cSCI).ResultsA sensor type that displayed a stable output signal over time was identified, and a high sensor resolution of 0.5° was obtained. The evaluation of the glove's reliability yielded high ICC values (0.84 to 0.92) with an accuracy error of about ± 5°. Feasibility testing revealed that the glove was sensitive to distinguish different levels of hand function impairment in cSCI patients.ConclusionsThe device satisfied the desired system requirements in terms of low cost, stable sensor signal over time, full finger-flexion range of motion tracking and capability to monitor all three joints of one finger. The developed rapid calibration system for easy use (high feasibility) and excellent psychometric properties (i.e. reliability and validity) qualify the device for the assessment of hand function in clinical practice and rehabilitation settings.

Focal hand dystonia

To examine whether the corticospinal system emanating from the primary motor cortex may be organized to facilitate generation of dystonic movements. In this cross-sectional observational study, finger movement (FM) representations were assessed in 10 patients with focal hand dystonia (FHD) and 10 matched healthy controls by transcranial magnetic stimulation during rest. Evoked finger movements of the right hand were recorded using an instrumented data glove. Patterns of finger joint movements were analyzed using cluster analysis. Principal component analysis and centers of gravity for finger movement representations and motor evoked potentials recorded from the abductor pollicis brevis and abductor digiti minimi muscles were computed. For comparison, high-resolution somatosensory evoked potentials (SSEP) were recorded after electrical stimulation of the thumb (D1) or little finger (D5) in the same patients. Source reconstruction for the N20 SSEP component was performed using a dual-dipole model. Stimulation of the resting motor cortex did not reveal overt abnormalities in FHD, neither with respect to finger joint movement patterns nor with respect to the topologic organization of finger movements or intrinsic hand muscle representations. However, in line with previous reports, the distance between the dipole sources of D1 and D5 in the somatosensory cortex (S1) was smaller in patients with FHD, suggesting disruption of homuncular finger representations in S1. Our findings may imply that abnormality of motor organization in focal hand dystonia arises principally only during activation, when abnormal somatosensory representations are functionally integrated.

Tiny lamps to illuminate the body

Biocompatible light-emitting structures based on high-performance inorganic compound semiconductors on flexible substrates open the path to futuristic therapeutic devices, instrumented surgical gloves and many other applications.

Comparative evaluation of static gesture recognition techniques based on nearest neighbor, neural networks and support vector machines

Abstract It is a common behavior for human beings to use gestures as a means of expression, as a complement to speaking, or as a self-contained communication mode. In the field of Human–Computer Interaction, this behavior can be adopted to build alternative interfaces, aiming to ease the relationship between the human element and the computational element. Currently, various gesture recognition techniques are described in the technical literature; however, the validation studies of these techniques are usually performed isolatedly, which complicates comparisons between them. To reduce this gap, this work presents a comparison between three well-established techniques for static gesture recognition, using Nearest Neighbor, Neural Networks, and Support Vector Machines as classifiers. These classifiers evaluate a common dataset, acquired from an instrumented glove, and generate results for precision and performance measurements. The results obtained show that the classifier implemented as a Support Vector Machine presented the best generalization, with the highest recognition rate. In terms of performance, all methods presented evaluation times fast enough to be used interactively. Finally, this work identifies and discusses a set of relevant criteria that must be observed for the training and evaluation steps, and its relation to the final results.

Use Of Non-invasive Markers For Early And Accurate Detection Of Traumatic Hemorrhage

Acute hemorrhage and subsequent circulatory collapse (shock) account for approximately 50% of the deaths on the battlefield and the forward operating table, a statistic that has remained relatively unchanged since World War I. Hemorrhage is defined as the escape of blood from a vessel and is the most common cause of hypovolemic shock. Current and classic techniques available to battlefield medics for triage and are focused on the traditional vital sign markers. Similarly, monitoring shock in the civilian trauma patient has also focused on the clinical "gold standard" assessments of Blood Pressure (BP), arterial O2 saturation or simple pulse palpation. However, these standard vital sign measurements fail to predict death or identify reductions in central blood volume until cardiovascular collapse has already occurred. About 10 percent of the total blood volume can be removed with almost no effect on either arterial pressure or cardiac output. PURPOSE: To develop and demonstrate a system that rapidly and non-invasively tracks vital sign markers throughout the progression of hemorrhage. METHODS: Orbital Research Inc (ORI) and Kent State University (KSU) used an incremental lower body negative pressure (LBNP) routine to safely educe physiologic changes like those typical to hemorrhage. Six research subjects have completed the study. An instrumented glove (developed by Orbital Research) collected vital signs intermittently and non-invasively during the experiment. Standards measure of metabolism; ECG and cardiac output were collected continuously. RESULTS: Using the instrumented glove to collect cardiovascular metrics, differences in R-R interval variability and Lf/Hf ratio are were detected during the LBNP sequence. Cardiac output, stroke volume and blood pressure data verified the physiologic compensations in response to the LBNP. CONCLUSIONS: Heart Rate Variability (HRV) has also shown promise and correlation to early reductions in central blood volume when blood pressures and SpO2 have not yet changed. This project demonstrated feasibility of using instrumented to glove to rapidly collect cardiovascular markers indicative of the onset of hemorrhage.

Force sensing system for automated assessment of motor performance during fMRI

Finger tapping sequences are a commonly used measure of motor learning in functional imaging studies. Subjects repeat a defined sequence of finger taps as fast as possible for a set period of time. The number of sequences completed per unit time is the measure of performance. Assessment of speed and accuracy is generally accomplished by video recording the session then replaying in slow motion to assess rate and accuracy. This is a time consuming and error prone process. Keyboards and instrumented gloves have also been used for task assessment though they are relatively expensive and not usually compatible in a magnetic resonance imaging (MRI) scanner. To address these problems, we developed a low cost system using MRI compatible force sensitive resistors (FSR) to assess the performance during a finger sequence task. This system additionally provides information on finger coordination including time between sequences, intervals between taps, and tap duration. The method was validated by comparing the FSR system results with results obtained by video analysis during the same session.

Compensatory motor control after stroke: an alternative joint strategy for object-dependent shaping of hand posture.

Efficient grasping requires planned and accurate coordination of finger movements to approximate the shape of an object before contact. In healthy subjects, hand shaping is known to occur early in reach under predominantly feedforward control. In patients with hemiparesis after stroke, execution of coordinated digit motion during grasping is impaired as a result of damage to the corticospinal tract. The question addressed here is whether patients with hemiparesis are able to compensate for their execution deficit with a qualitatively different grasp strategy that still allows them to differentiate hand posture to object shape. Subjects grasped a rectangular, concave, and convex object while wearing an instrumented glove. Reach-to-grasp was divided into three phases based on wrist kinematics: reach acceleration (reach onset to peak horizontal wrist velocity), reach deceleration (peak horizontal wrist velocity to reach offset), and grasp (reach offset to lift-off). Patients showed reduced finger abduction, proximal interphalangeal joint (PIP) flexion, and metacarpophalangeal joint (MCP) extension at object grasp across all three shapes compared with controls; however, they were able to partially differentiate hand posture for the convex and concave shapes using a compensatory strategy that involved increased MCP flexion rather than the PIP flexion seen in controls. Interestingly, shape-specific hand postures did not unfold initially during reach acceleration as seen in controls, but instead evolved later during reach deceleration, which suggests increased reliance on sensory feedback. These results indicate that kinematic analysis can identify and quantify within-limb compensatory motor control strategies after stroke. From a clinical perspective, quantitative study of compensation is important to better understand the process of recovery from brain injury. From a motor control perspective, compensation can be considered a model for how joint redundancy is exploited to accomplish the task goal through redistribution of work across effectors.

An instrumented glove for small primates

The Cymanus is a novel flex sensor glove for measuring hand kinematics in primates. It was used to monitor 9 joints of a rhesus macaque performing a grasping task with 25 objects. Over 6 days, the monkey tolerated the glove and showed no significant impairment in performance. The sensors linearly tracked joint angles, with joint trajectories preserved over days. Angular positions discriminated objects as accurately as electromyograms recorded simultaneously from 24 arm and hand muscles, and were maximally informative of object identity at the end of reach-to-grasp. In a further validation of the glove, muscle activity controlling a joint was correlated with the joint's angular acceleration 70 ms later.

First characterization of the expiratory flow increase technique: method development and results analysis

This study provides an important contribution to the definition of the expiratory flow increase technique (EFIT). So far, no measuring means were suited to assess the manual EFIT performed on infants. The proposed method aims at objectively defining the EFIT based on the quantification of pertinent cognitive parameters used by physiotherapists when practicing. We designed and realized customized instrumented gloves endowed with pressure and displacement sensors, and the associated electronics and software. This new system is specific to the manoeuvre, to the user and innocuous for the patient. Data were collected and analysed on infants with bronchiolitis managed by an expert physiotherapist. The analysis presented is realized on a group of seven subjects (mean age: 6.1 months, SD: 1.1; mean chest circumference: 44.8 cm, SD: 1.9). The results are consistent with the physiotherapist's tactility. In spite of inevitable variability due to measurements on infants, repeatable quantitative data could be reported regarding the manoeuvre characteristics: the magnitudes of displacements do not exceed 10 mm on both hands; the movement of the thoracic hand is more vertical than the movement of the abdominal hand; the maximum applied pressure with the thoracic hand is about twice higher than with the abdominal hand; the thrust of the manual compression lasts (590 ± 62) ms. Inter-operators measurements are in progress in order to generalize these results.

Virtual reality to maximize function for hand and arm rehabilitation: exploration of neural mechanisms.

Stroke patients report hand function as the most disabling motor deficit. Current evidence shows that learning new motor skills is essential for inducing functional neuroplasticity and functional recovery. Adaptive training paradigms that continually and interactively move a motor outcome closer to the targeted skill are important to motor recovery. Computerized virtual reality simulations when interfaced with robots, movement tracking and sensing glove systems, are particularly adaptable, allowing for online and offline modifications of task based activities using the participant's current performance and success rate. We have developed a second generation system that can exercise the hand and the arm together or in isolation and provide for both unilateral and bilateral hand and arm activities in three-dimensional space. We demonstrate that by providing haptic assistance for the hand and arm and adaptive anti-gravity support, the system can accommodate patients with lower level impairments. We hypothesize that combining training in virtual environments (VE) with observation of motor actions can bring additional benefits. We present a proof of concept of a novel system that integrates interactive VE with functional neuroimaging to address this issue. Three components of this system are synchronized, the presentation of the visual display of the virtual hands, the collection of fMRI images and the collection of hand joint angles from the instrumented gloves. We show that interactive VEs can facilitate activation of brain areas during training by providing appropriately modified visual feedback. We predict that visual augmentation can become a tool to facilitate functional neuroplasticity.

A Novel Functional Electrical Stimulation Treatment for Recovery of Hand Function in Hemiplegia: 12-Week Pilot Study

Background. Loss of finger extension is common after stroke and can severely limit hand function. Contralaterally controlled functional electrical stimulation (CCFES) is a new treatment aimed at restoring volitional finger and thumb extension. A previous pilot study showed reductions in hand impairment after 6 weeks of CCFES, but the effect did not persist after end of treatment. Objective. This study aimed to evaluate the feasibility of achieving greater and more persistent gains with CCFES by increasing the treatment period to 12 weeks. Methods. CCFES uses neuromuscular electrical stimulation to open the paretic hand in direct proportion to the degree of volitional opening of the unimpaired contralateral hand, which is detected by an instrumented glove. Three subjects with chronic hemiplegia participated in a 12-week CCFES treatment, which consisted of daily CCFES-assisted active repetitive hand-opening exercises and twice weekly functional task practice with CCFES. Results. Maximum voluntary finger extension increased by 101° and 68° for subjects 1 and 2, respectively, but subject 3 had no improvement in finger extension. Box and Block score increased by 6, 15, and 7 blocks, and upper extremity Fugl-Meyer score increased by 11, 15, and 7 points for subjects 1, 2, and 3, respectively. The finger extension gains declined at the 1-month and 3-month follow-up for subjects 1 and 2, but the gains in Box and Block and Fugl-Meyer scores persisted at follow-up. Conclusions. Greater reductions in hand impairment were achieved by extending the treatment period. The effect and its longevity may be related to baseline impairment level.

Prediction of fingers posture using artificial neural networks

Predicting the hand and fingers posture during grasping tasks is an important issue in the frame of biomechanics. In this paper, a technique based on neural networks is proposed to learn the inverse kinematics mapping between the fingertip 3D position and the corresponding joint angles. Finger movements are obtained by an instrumented glove and are mapped to a multichain model of the hand. From the fingertip desired position, the neural networks allow predicting the corresponding finger joint angles keeping the specific subject coordination patterns. Two sets of movements are considered in this study. The first one, the training set, consisting of free fingers movements is used to construct the mapping between fingertip position and joint angles. The second one, constructed for testing purposes, is composed of a sequence of grasping tasks of everyday-life objects. The maximal mean error between fingertip measured position and fingertip position obtained from simulated joint angles and forward kinematics is 0.99±0.76 mm for the training set and 1.49±1.62 mm for the test set. Also, the maximal RMS error of joint angles prediction is 2.85° and 5.10° for the training and test sets respectively, while the maximal mean joint angles prediction error is −0.11±4.34° and −2.52±6.71° for the training and test sets, respectively. Results relative to the learning and generalization capabilities of this architecture are also presented and discussed.

Hand-Gesture Computing for the Hearing and Speech Impaired

An instrumented data glove with a wireless interface provides convenient and natural human- computer interaction for people with speech or hearing impairments.

Contributions of Online Visual Feedback to the Learning and Generalization of Novel Finger Coordination Patterns

We explored how people learn new ways to move objects through space using neuromuscular control signals having more degrees of freedom than needed to unambiguously specify object location. Subjects wore an instrumented glove that recorded finger motions. A linear transformation matrix projected joint angle signals (a high-dimensional control vector) onto a two-dimensional cursor position on a video monitor. We assessed how visual information influences learning and generalization of novel finger coordination patterns as subjects practiced using hand gestures to manipulate cursor location. Three groups of test subjects practiced moving a visible cursor between different sets of screen targets. The hand-to-screen transformation was designed such that the different sets of targets (which we called implicit spatial cues) varied in how informative they were about the gestures to be learned. A separate control group practiced gesturing with explicit cues (pictures of desired gestures) without ongoing cursor feedback. Another control group received implicit spatial cueing and feedback only of final cursor position. We found that test subjects and subjects provided with explicit cues could learn to produce desired gestures, although training efficacy decreased as the amount of task-relevant feedback decreased. Although both control groups learned to associate screen targets with specific gestures, only subjects provided with online feedback of cursor motion learned to generalize in a manner consistent with the internal representation of an inverse hand-to-screen mapping. These findings suggest that spatial learning and generalization require dynamic feedback of object motion in response to control signal changes; static information regarding geometric relationships between controller and endpoint configurations does not suffice.

Evaluation of hand grasping by instrumented glove

In this paper the evaluation of effectivenes of instrumented glove in measurement of hand opening and preshaping during reach-to-grasp movement is described. In the experiment presented in this wor...

Assessing joint angles in human hand via optical tracking device and calibrating instrumented glove

The aim of this paper is to present a method for assessing joint angles in a human hand: a method suitable for the calibration of an instrumented glove. The method is based on an optical tracking device and an inverse-kinematic model of the human hand. It requires only one reflective marker to be attached to each finger and three on the dorsal aspect of the hand in order to assess angles in finger joints. A further three markers are needed to calculate angles in thumb joints. Joint angles assessed through inverse kinematics and with the calibrated glove were validated against reference angles calculated from the centers of rotation of the joints while measuring the finger movements with multiple markers. In fingers, the mean difference between the reference angles and the angles assessed by the glove did not exceed ±7° when the proposed model-based method was used to calibrate the glove. For the thumb the mean error did not exceed ±5° when the reference method was used to calibrate the glove.