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

Joint Stiffness Compensation for Application in the EXTEND Hand Orthosis

This paper presents a passive hand orthosis, called EXTEND, that can be used during activities of daily living. In the design a negative stiffness spring mechanism is incorporated to overcome the high finger joint stiffness of stroke patients with hypertonia. The passive mechanism can be easily tuned by the user to compensate a linear joint stiffness of 0.15 to 0.33 Nm/rad for each finger independently. A prototype was tested with four patients showing an increased functional ability of the hand during several tasks. With the orthosis, patients were better able to pick up mid-sized objects (5-7.5cm diameter) of different shapes.</p

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

Pushing the limits: A novel tape spring pushing mechanism to be used in a hand orthosis

A device that supports hand function may significantly improve the quality of life of patients with muscular weakness. Since tight constraints such as size and weight are placed upon the device, complexity of the hardware and functional performance should be carefully balanced. A novel force transmission mechanism based on tape springs is presented for use in a hand orthosis. The actuator force is transmitted to the finger by a system consisting of a tape spring, two slider blocks and an end stop per finger. The tape spring allows for bending in one direction, and resists bending in the other direction. A prototype with the new mechanism is constructed. The low profile together with the ability to transmit large forces makes this mechanism suitable for hand orthoses

Joint Stiffness Compensation for Application in the EXTEND Hand Orthosis

This paper presents a passive hand orthosis, called EXTEND, that can be used during activities of daily living. In the design a negative stiffness spring mechanism is incorporated to overcome the high finger joint stiffness of stroke patients with hypertonia. The passive mechanism can be easily tuned by the user to compensate a linear joint stiffness of 0.15 to 0.33 Nm/rad for each finger independently. A prototype was tested with four patients showing an increased functional ability of the hand during several tasks. With the orthosis, patients were better able to pick up mid-sized objects (5-7.5cm diameter) of different shapes

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