Evaluating the clinical effects of a dynamic shoulder orthosis.

BACKGROUND: Shoulder orthoses reduce the gravitational pull on the shoulder by providing an upward force to the arm, which can decrease shoulder pain caused by stress on the glenohumeral structures. OBJECTIVE: In this interventional study, the clinical effects of a recently developed dynamic shoulder orthosis were assessed in 10 patients with chronic shoulder pain. The shoulder orthosis provides an upward force to the arm with 2 elastic bands. These bands are arranged to statically balance the arm, such that the supportive force is always directed toward the glenohumeral joint and shoulder movements are not impeded. STUDY DESIGN: Clinical effect study. METHODS: The study population was provided with a dynamic shoulder orthosis for 2 weeks. In the week before the orthosis fitting, the participants had no intervention. The primary outcome measures were the mean shoulder pain scores before and during the intervention, and the distance between the humeral head and the acromion without and with orthosis. RESULTS: Ultrasound evaluation showed that the shoulder orthosis resulted in a reduction of the distance between the acromion and humeral head at different levels of arm support. In addition, it was demonstrated that the mean shoulder pain scores (range 0-10) decreased from 3.6 to 3 (in rest) and from 5.3 to 4.2 (during activities) after 2 weeks of orthosis use. In general, patients were satisfied with the weight, safety, ease in adjusting, and effectiveness of the orthosis. CONCLUSIONS: The results of this study show that the orthosis has the potential to reduce shoulder complaints in patients with chronic shoulder pain.

System identification: a feasible, reliable and valid way to quantify upper limb motor impairments.

BACKGROUND: Upper limb impairments in a hemiparetic arm are clinically quantified by well-established clinical scales, known to suffer poor validity, reliability, and sensitivity. Alternatively, robotics can assess motor impairments by characterizing joint dynamics through system identification. In this study, we establish the merits of quantifying abnormal synergy, spasticity, and changes in joint viscoelasticity using system identification, evaluating (1) feasibility and quality of parametric estimates, (2) test-retest reliability, (3) differences between healthy controls and patients with upper limb impairments, and (4) construct validity. METHODS: Forty-five healthy controls, twenty-nine stroke patients, and twenty cerebral palsy patients participated. Participants were seated with the affected arm immobilized in the Shoulder-Elbow-Perturbator (SEP). The SEP is a one-degree-of-freedom perturbator that enables applying torque perturbations to the elbow while providing varying amounts of weight support to the human arm. Participants performed either a 'do not intervene' or a resist task. Elbow joint admittance was quantified and used to extract elbow viscosity and stiffness. Fifty-four of the participants performed two sessions to establish the test-retest reliability of the parameters. Construct validity was assessed by correlating system identification parameters to parameters extracted using a SEP protocol that objectifies current clinical scales (Re-Arm protocol). RESULTS: Feasibility was confirmed by all participants successfully completing the study protocol within ~ 25 min without reporting pain or burden. The parametric estimates were good with a variance-accounted-for of ~ 80%. A fair to excellent test-retest reliability was found ([Formula: see text]) for patients, except for elbow stiffness with full weight support ([Formula: see text]). Compared to healthy controls, patients had a higher elbow viscosity and stiffness during the 'do not intervene' task and lower viscosity and stiffness during the resist task. Construct validity was confirmed by a significant (all [Formula: see text]) but weak to moderate ([Formula: see text]) correlation with parameters from the Re-Arm protocol. CONCLUSIONS: This work demonstrates that system identification is feasible and reliable for quantifying upper limb motor impairments. Validity was confirmed by differences between patients and controls and correlations with other measurements, but further work is required to optimize the experimental protocol and establish clinical value.

Mechanical design and feasibility of a finger exoskeleton to support finger extension of severely affected stroke patients.

In this paper we presented the mechanical design and evaluation of a low-profile and lightweight exoskeleton that supports the finger extension of stroke patients during daily activities without applying axial forces to the finger. The exoskeleton consists of a flexible structure that is secured to the index finger of the user while the thumb is fixed in an opposed position. Pulling on a cable will extend the flexed index finger joint such that objects can be grasped. The device can achieve a grasp size of at least 7 cm. Technical tests confirmed that the exoskeleton was able to counteract the passive flexion moments corresponding to the index finger of a severely affected stroke patient (with an MCP joint stiffness of k = 0.63Nm/rad), requiring a maximum cable activation force of 58.8N. A feasibility study with stroke patients (n=4) revealed that the body-powered operation of the exoskeleton with the contralateral hand caused a mean increase of 46° in the range of motion of the index finger MCP joint. The patients (n=2) who performed the Box & Block Test were able to grasp and transfer maximally 6 blocks in 60 sec. with exoskeleton, compared to 0 blocks without exoskeleton. Our results showed that the developed exoskeleton has the potential to partially restore hand function of stroke patients with impaired finger extension capabilities. An actuation strategy that does not involve the contralateral hand should be implemented during further development to make the exoskeleton suitable for bimanual daily activities.

Feasibility of reconstructing the glenohumeral center of rotation with a single camera setup.

BACKGROUND: An accurate estimation of the glenohumeral joint center of rotation (CoR) is important during alignment of braces and exoskeletons, as a misalignment will introduce undesired forces on the human body. The aim of this research was to develop a new method to estimate the glenohumeral CoR and register the location to the body using a single camera and two printed markers. METHODS: During shoulder anteflexion, the arm roughly describes an arc in the sagittal plane, with the glenohumeral joint in the center. Two binary square-fiducial ArUco markers were secured to the upper arm and the scapula, their position and orientation were obtained, and a sphere was fitted to the coordinates of the arm marker. The sphere center position was then registered on the skin. The accuracy was assessed with a test bench with a known rotational center. The repeatability was assessed in vivo with five healthy participants. RESULTS: The mean absolute offset between the true CoR of the test bench and the fitted sphere centers across multiple trials was 2.7 mm at a velocity of 30 degrees/s, and 2.5 mm at 60 degrees/s. The root mean squared distance from the estimated sphere centers after each trial to the mean sphere center across all trials per participant was 5.1 mm on average for the novice examiner and 5.2 mm for the expert examiner. CONCLUSIONS: The proposed method is able to accurately and precisely estimate the glenohumeral CoR.

Design and feasibility of the T-GRIP thumb exoskeleton to support the lateral pinch grasp of spinal cord injury patients.

Improving the impaired hand function of spinal cord injury patients with a robotic exoskeleton can highly impact their self-management, and ultimately their quality of life. In this paper the design and evaluation of a new, lightweight (50 gram) robotic thumb exoskeleton, called TGRIP, was presented that supports the lateral pinch grasp. The mechanism consists of a linear actuator that was mounted to the dorsal side of the hand, and a force transmission mechanism that flexes the thumb towards the side of the index finger. The thumb movement was controlled through contralateral wrist rotation. Experimental results from an evaluation with three spinal cord injury patients showed that the achieved grip force (~ 7N) was higher and the overall performance during the Grasp and Release Test was better with the T-GRIP than without device. The device shows great potential for improving the hand function of patients with cervical spinal cord injury by actuating only a single degree of freedom.

Accurate Estimation of Upper Limb Orthosis Wear Time Using Miniature Temperature Loggers.

OBJECTIVE: To propose and validate a new method for estimating upper limb orthosis wear time using miniature temperature loggers attached to locations on the upper body. DESIGN: Observational study. SUBJECTS: Fifteen healthy participants. METHODS: Four temperature loggers were attached to the arm and chest with straps. Participants were asked to remove and re-attach the straps at specified time-points. The labelled temperature data obtained were used to train a decision tree classification algorithm to estimate wear time. The final performance (mean error and 95% confidence interval) of the trained classifier and the wear time estimation were assessed with a hold-out data-set. RESULTS: The trained algorithm can correctly classify unseen temperature data with a mean classification error between 1.1% and 3.1% for the arm, and between 1.8% and 4.0% for the chest, depending on the sampling time of the temperature logger. This resulted in mean wear time errors between 0.5% and 8.3% for the arm, and 0.13% and 13.0% for the chest. CONCLUSION: The proposed method based on a classifier can accurately estimate upper limb orthosis wear time. This method could enable healthcare professionals to gain insight into the wear time of any upper limb orthosis.

A newly designed shoulder orthosis for patients with glenohumeral subluxation: a clinical evaluation study.

BACKGROUND: Shoulder complaints from glenohumeral subluxation are a common problem and limit patients during daily activities. OBJECTIVE: To assess the clinical pros and cons and usability of a newly developed shoulder orthosis (Roessingh Omo Support [ROS]) in patients with chronic shoulder complaints. STUDY DESIGN: Retrospective cross-sectional study. METHODS: All patients older than 18 years who received the ROS were invited. Medical information was collected from medical records. Two questionnaires were sent to the patient: The "Shoulder Rating Questionnaire" (SRQ, max 100 points) for evaluation before and during use and a custom orthosis usability questionnaire. RESULTS: In total, 28 patients (34 orthoses) participated in the study. Neuralgic amyotrophy was the most common diagnosis (64.3%). The SRQ showed a significant positive change of 8.9 points (from 35.0 [SD 12.6] to 43.9 [SD 14.3]). The most described goal was pain reduction (76.5%). 47.1% of the patients achieved their goal(s), and 71.4% were still using the orthosis. The mean satisfaction rate was 7.1 (SD 1.4). CONCLUSION: The use of the ROS shows a significant functional improvement (SRQ), a decrease of pain, and a high degree of satisfaction, although the individual experiences of the patients are highly variable. Some modifications to the design to improve comfort may be needed.

A New Shoulder Orthosis to Dynamically Support Glenohumeral Subluxation.

OBJECTIVE: In this paper we presented a novel shoulder subluxation support that aims to reduce the stress on the passive structures around the shoulder of patients with glenohumeral subluxation and glenohumeral-related shoulder pain. The device applies a force to the upper arm without impeding the functional range of motion of the arm. Our design contains a mechanism that statically balances the arm with two elastic bands. METHODS: A technical evaluation study was conducted to assess the performance of the orthosis. Additionally, two patients evaluated the orthosis. RESULTS: The results of the technical validation confirm the working of the balancing mechanism. The pilot study demonstrated that the shoulder support increased the feeling of stability of the shoulder joint and, to a lesser extent, decreased shoulder pain. Furthermore, both patients reported that the orthosis did not impede their range of motion. CONCLUSION: In this research we developed a shoulder orthosis based on two statically balanced springs that support the shoulder of patients with glenohumeral subluxation that have residual shoulder muscle force. Compared to existing shoulder supports, our design does not impede the range of motion of the arm, and continues to provide a stabilizing force to the shoulder, even if the arm is moved away from the neutral position. Tests with two participants showed promising results. SIGNIFICANCE: The device presented in this work could have a significant impact on the shoulder function which may improve rehabilitation outcome and improve the quality of life of patients suffering from glenohumeral subluxation and shoulder pain.

A Novel Soft Robotic Supernumerary Hand for Severely Affected Stroke Patients.

Upper limb functions are severely affected in 23% of the chronic stroke patients, compromising their life quality. To re-enable hand use, providing a degree of functionality and motivating against learned non-use, we propose a robotic supernumerary limb, the SoftHand X (SHX), consisting of a robotic hand, a gravity support system, and different sensors to detect the patient's intent for controlling the robotic hand. In this paper, this novel compensational approach is introduced and experimentally evaluated in stroke patients, assessing its efficacy, usability and safety. Ten patients were asked to perform tasks of a modified Action Research Arm Test with the SHX, by using three input methods. The mARAT scores rated the potentiality of the system. Usability was evaluated with the System Usability Scale, while spasticity before and after use was measured by the modified Ashworth Scale (mAS). Nine patients, not able to perform any tasks without external support, completed the whole experimental procedure using the proposed system with a median score greater than 12/30. Among the three input methods tested, the usability of one was rated as "good" while the other two were rated as "ok". Seven patients exhibited a reduction of the mAS. All nine patients stated that they would use the system frequently. Results obtained suggest that the SHX has the potential to partially compensate severely impaired hand function in stroke patients.

A structured overview of trends and technologies used in dynamic hand orthoses.

The development of dynamic hand orthoses is a fast-growing field of research and has resulted in many different devices. A large and diverse solution space is formed by the various mechatronic components which are used in these devices. They are the result of making complex design choices within the constraints imposed by the application, the environment and the patient's individual needs. Several review studies exist that cover the details of specific disciplines which play a part in the developmental cycle. However, a general collection of all endeavors around the world and a structured overview of the solution space which integrates these disciplines is missing. In this study, a total of 165 individual dynamic hand orthoses were collected and their mechatronic components were categorized into a framework with a signal, energy and mechanical domain. Its hierarchical structure allows it to reach out towards the different disciplines while connecting them with common properties. Additionally, available arguments behind design choices were collected and related to the trends in the solution space. As a result, a comprehensive overview of the used mechatronic components in dynamic hand orthoses is presented.