Multimodal sensorimotor assessment of hand and forearm asymmetries: a reliability and correlational study.

Background: Effective rehabilitation of upper limb musculoskeletal disorders requires multimodal assessment to guide clinicians' decision-making. Furthermore, a comprehensive assessment must include reliable tests. Nevertheless, the interrelationship among various upper limb tests remains unclear. This study aimed to evaluate the reliability of easily applicable upper extremity assessments, including absolute values and asymmetries of muscle mechanical properties, pressure pain threshold, active range of motion, maximal isometric strength, and manual dexterity. A secondary aim was to explore correlations between different assessment procedures to determine their interrelationship. Methods: Thirty healthy subjects participated in two experimental sessions with 1 week between sessions. Measurements involved using a digital myotonometer, algometer, inclinometer, dynamometer, and the Nine-Hole Peg test. Intraclass correlation coefficients, standard error of the mean, and minimum detectable change were calculated as reliability indicators. Pearson's correlation was used to assess the interrelationship between tests. Results: For the absolute values of the dominant and nondominant sides, reliability was 'good' to 'excellent' for muscle mechanical properties, pressure pain thresholds, active range of motion, maximal isometric strength, and manual dexterity. Similarly, the reliability for asymmetries ranged from 'moderate' to 'excellent' across the same parameters. Faster performance in the second session was consistently found for the Nine-Hole Peg test. No systematic inter-session errors were identified for the values of the asymmetries. No significant correlations were found between tests, indicating test independence. Conclusion: These findings indicate that the sensorimotor battery of tests is reliable, while monitoring asymmetry changes may offer a more conservative approach to effectively tracking recovery of upper extremity injuries.

Biomechanical assessment of the central band of the interosseous membrane using shear wave elastography: reliability and reproducibility.

The interosseous membrane of the forearm is an essential structure for the stability of the forearm skeleton, the most important part being the central band. The purpose of this study was to determine if shear wave elastography, a non-invasive ultrasound technique, can be used to measure shear wave speed in the central band and quantify stiffness. Fifteen healthy adult subjects were included (30 forearms). The participants forearms were positioned on an articulated plate, with their hand in neutral, pronated and then supinated positions of 30°, 60° and 90°. The shear wave speed was highest in 90° pronation (4.4 m/s (SD 0.3)) and 90° supination (4.4 m/s (SD 0.27)) indicating maximum stiffness in these positions. Its minimum value was in the neutral position, and either in 30° pronation or supination (3.5 m/s (SD 0.3)). Intra- and interobserver agreement was excellent, regardless of probe positioning or forearm mobilization. This study presents a reliable shear wave elastography measurement protocol to describe the physiological function of the central band of the interosseous membrane in healthy adults.Level of evidence: IV.

An electromyographic assessment pilot study on the reliability of the forearm muscles during multi-planar maximum voluntary contraction grip and wrist articulation in young males.

BACKGROUND: Electromyographic systems are widely used in scientific and clinical practice. The reproducibility and reliability of these measures are crucial when conducting scientific research and collecting experimental data. OBJECTIVE: To test the reliability of surface electromyography signals from both the Flexor Digitorum Superficialis (FDS) and Extensor Carpi Radialis Brevis (ECRB) muscles of both the left and right arms during an individual, static multi-planar maximum voluntary contraction handgrip task using the Myon 320 system (Myon AG, Switzerland). METHODS: Eight right-handed male participants performed two maximal handgrip tests in five separate wrist positions using both hands. Muscle activity was recorded from both forearms. Reliability was measured using the Standard Error of Measurement (SEM), Coefficient of Variation (CV) and Intra-class correlation coefficients. Wrist joint position correlations within and between the FDS and ECRB muscle activities were also analysed. RESULTS: Absolute reliability was shown across all positions for both hands with CV and SEM recorded at below 10%. The output measures indicate that the Myon 320 system (Myon AG, Switzerland) produces good to fair reliability when assessing forearm muscle activity. Correlations in the left FDS muscles were negative. Correlations between the left ECRB and left FDS muscles were variable but positive between the right ECRB and right FDS muscles. CONCLUSIONS: The data sets retrieved from all participants were reliably evaluated. Wrist position correlations within and between the FDS and ECRB muscles may have been influenced by hand dominance. The findings demonstrate that the methods and systems outlined in this study can be used reliably in future research.

Process of Obtaining Social Consensus and 3-Year Functional Outcomes of the First Hand Allotransplantation in Korea.

BACKGROUND: On February 2, 2017, the surgical team of ten board-certified hand specialists of W Hospital in Korea successfully performed the nation's first hand transplantation at Yeungnam University Medical Center (YUMC). This paper reports on the legal, financial, and cultural hurdles that were overcome to open the way for hand transplantation and its functional outcomes at 36 months after the operation. METHODS: W Hospital formed a memorandum of understanding with Daegu city and YUMC to comply with government regulations regarding hand transplantation. Campaigns were initiated in the media to increase public awareness and understanding. With the city's financial and legal support and the university's medical cooperation, a surgical team performed a left distal forearm hand transplantation from a brain-dead 48-year-old man to a 35-year-old left-handed man. RESULTS: With this successful allotransplantation, the Korean Act on Organ Transplantation has now been amended to include hand transplantation. Korean national health insurance has also begun covering hand transplantation. Functional outcome at 36 months after the operation showed satisfactory progress in both motor and sensory functions. The disabilities of the arm, shoulder, and hand score were 23. The final Hand Transplantation Score was 90 points. Functional brain magnetic resonance imaging shows significant cortical reorganization of the corticospinal tract, and reinnervation of intrinsic muscle is observed. CONCLUSIONS: Hand transplantation at the distal forearm shows very satisfactory outcomes in functional, aesthetical, and psychological aspects. Legal and financial barriers against hand transplantation have long been the most burdensome issues. Despite this momentous success, there have been no other clinical applications of vascularized composite allotransplantation due to the limited acceptance by Korean doctors and people. Further public education campaigns for vascularized composite allotransplantation are needed to increase awareness and acceptance.

Ergonomic assessment of a new hand tool design for laparoscopic surgery based on surgeons' muscular activity.

Laparoscopic surgery techniques are customarily used in non-invasive procedures. That said traditional surgical instruments and devices used by surgeons suffer from certain ergonomic deficiencies that may lead to physical complaints in upper limbs and back and general discomfort that may, in turn, affect the surgeon's skills during surgery. A novel design of the laparoscopic gripper handle is presented and compared with one of the most used instruments in this field in an attempt to overcome this problem. The assessment of the ergonomic feature of the novel design was performed by using time-frequency analysis of the surface electromyography (sEMG) signal during dynamic activities. Singular Spectrum Analysis (SSA) was used to decompose the sEMG signal and extract the median frequency of each muscle to assess muscle fatigue. The results reveal that using the proposed ergonomic grip reduces the mean values of the muscle activity during each of the proposed tasks. The novel design also improves the ease of use in laparoscopic surgery as it minimises high-pressure contact areas, reduces large amplitude movements and promotes a neutral position of the hand, wrist and forearm. Furthermore, the SSA method for time-frequency analysis provides a powerful tool to analyse a prescribed activity in ergonomic terms. The proposed methodology to assess muscle activity during surgery activities may be useful in the selection of surgical instruments when programming extended procedures, as it provides an additional selection criterion based on the surgeon's biomechanics and the proposed activity.

Cost-Effectiveness of Titanium Elastic Nail (TEN) in the Treatment of Forearm Fractures in Children.

Background and objectives: There are various methods in the management of forearm fractures in children. Elastic stable intramedullary nailing using Titanium Elastic Nail (TEN) is nowadays employed in diaphysis fractures of children, with clear benefits over other treatment options. However, in the case of TEN versus other treatment methods of forearm fractures in children, cost is an important issue. This report will focus on the cost assessment of using TEN versus other therapeutic means in the treatment of forearm fractures in children. Materials and Methods: We performed a retrospective longitudinal study of 173 consecutive patients with forearm fractures treated in a single institution during 2017. We calculated the cost for each patient by summing up direct costs plus indirect costs, calculated at an aggregate level. Hospital income data were extracted from the Diagnosis Related Groups database. Results: A total of 173 patients with forearm fractures were treated, 44 using TEN, 86 using K-wire, and 46 using closed reduction and cast. There were 66 radius fractures, 1 ulna fracture, and 106 that were both radius and ulna fractures. Mean treatment cost were $632.76 for TEN, $499.50 for K-wire, and $451.30 for closed reduction and cast. Costs for TEN were higher than for K-wire insertion (p = 0.00) and higher than closed reduction and cast ($182.42; p = 0.00). Reimbursement per patient was higher with TEN versus K-wire patients; $497.88 vs. $364.64 /patient (p = 0.00), and higher than for patients treated with closed reduction and cast (p = 0.00). Conclusions: The treatment of upper extremity fractures using TEN was more expensive than the other methods. In Romania, because the reimbursement for TEN is higher as well, there are no differences in the financial burden when treating forearm fractures with TEN versus K-wire. Non-surgical treatment has the lowest cost but also the lowest reimbursement.

Using infrared imaging for assessment of muscular activity in the forearm of surgeons in the performance of laparoscopic tasks.

Surgeons working in laparoscopic surgery are subjected to hard working conditions because of the poor ergonomic characteristics of the workplace. The improvement in the working conditions requires the use of reliable techniques for the assessment of muscular activity. In this article infrared imaging is used and compared with electromyography for the evaluation of muscle activity in the performance of laparoscopic surgical tasks. Electromyography has been widely used for the evaluation of the electrical activity produced by the muscles in the performance of surgery. On the contrary, infrared imaging is an innovative technique that has not been sufficiently explored. An experimental evaluation was carried out using a thermography camera and recording the infrared images from volunteers in different tests. Pearson's correlation was obtained between the electromyography and thermographic measurements in two stages: Endurance Stage (best value: ρ = 0.8401 with p < 0.01) and Surgical Task (best value: ρ = 0.8309 with p < 0.01). The article demonstrates that infrared imaging is a valuable technique for the evaluation of muscle activity in laparoscopic surgery, and it can be compared with electromyography. The main advantages of infrared imaging are that it allows remote measurement and provides activity information in the whole area of interest. However, drawbacks such as delayed response of the infrared imaging due to thermal conductivity of the skin should be considered. Electromyography only provides information in the location of the electrodes, but it is a real-time response. For these reasons, the techniques complement each other.

Tissue oxygen saturation assessment of microvascular perfusion in adults with Fontan palliation and comparator groups using vascular optical spectrophotometry: a pilot study.

OBJECTIVE: The Fontan operation greatly improves survival for single ventricle congenital heart disease patients but creates a physiology that leads to long-term multi-organ dysfunction. A non-invasive screening tool that can identify impending decline is sought. The objective of this pilot study was to assess the microcirculation in Fontan-palliated patients by measuring tissue oxygen saturation (StO2) in superficial and deeper tissues. APPROACH: Three patient cohorts were studied: Fontan group (n = 8) and two patient control groups, liver disease group (n = 8) and tetralogy of Fallot group (n = 9). 22 healthy controls were also examined. Superficial and deeper StO2 was measured at the forearm, thenar eminence, index and ring fingers of both arms using the LEA O2C spectrophotometry device. MAIN RESULTS: Superficial StO2 was reduced in Fontan patients compared to healthy controls (p  = 0.002) and tetralogy patients (p  = 0.016), but not compared to the liver group (p  = 0.313). Deeper StO2 was similar between groups (p  = 0.112). The gap between deeper and superficial StO2 was raised in Fontan patients compared to healthy controls (p  = 0.001) and tetralogy patients (p  = 0.037), but not compared to the liver group (p  = 0.504). There was no clinically relevant difference in StO2 between the left and right arms, and the variation in StO2 according to measurement site was similar between the four groups. SIGNIFICANCE: Vascular optical spectrophotometry is a feasible non-invasive measure of micro-circulatory function that can easily be performed in the clinic setting and may have utility in patients with Fontan circulations. Further, we provide important normal range data in the healthy control population which can be used to design future studies.

Reliability of forearm oxygen uptake during handgrip exercise: assessment by ultrasonography and venous blood gas.

Assessment of forearm oxygen uptake (V˙O2 ) during handgrip exercise is a keenly investigated concept for observing small muscle mass metabolism. Although a combination of Doppler ultrasound measurements of brachial artery blood flow (Q˙) and blood gas drawn from a deep forearm vein has been utilized to calculate forearm V˙O2 for more than two decades, the applicability of this experimental design may benefit from a thorough evaluation of its reliability during graded exercise. Therefore, we evaluated the reliability of this technique during incremental handgrip exercise in ten healthy young (24 ± 3(SD) years.) males. V˙O2 and work rate (WR) exhibited a linear relationship (1.0 W: 43.8 ± 10.1 mL·min-1 ; 1.5 W: 53.8 ± 14.1 mL·min-1 ; 2.0 W: 63.4 ± 16.3 mL·min-1 ; 2.5 W: 72.2 ± 17.6 mL·min-1 ; 3.0 W: 79.2 ± 18.6 mL·min-1 ; r = 0.65, P < 0.01). In turn, V˙O2 was strongly associated with Q˙ (1.0 W: 359 ± 86 mL·min-1 ; 1.5 W: 431 ± 112 mL·min-1 ; 2.0 W: 490 ± 123 mL·min-1 ; 2.5 W: 556 ± 112 mL·min-1 ; 3.0 W: 622 ± 131 mL·min-1 ; r = 0.96; P < 0.01), whereas arteriovenous oxygen difference (a-vO2diff ) remained constant following all WRs (123 ± 11-130 ± 10 mL·L-1 ). Average V˙O2 test-retest difference was -0.4 mL·min-1 with ±2SD limits of agreement (LOA) of 8.4 and -9.2 mL·min-1 , respectively, whereas coefficients of variation (CVs) ranged from 4-7%. Accordingly, test-retest Q˙ difference was 11.9 mL·min-1 (LOA: 84.1 mL·min-1 ; -60.4 mL·min-1 ) with CVs between 4 and 7%. Test-retest difference for a-vO2diff was -0.28 mL·dL-1 (LOA: 1.26mL·dL-1 ; -1.82 mL·dL-1 ) with 3-5% CVs. In conclusion, our results revealed that forearm V˙O2 determination by Doppler ultrasound and direct venous sampling is linearly related to WR, and a reliable experimental design across a range of exercise intensities.

Assessment of normal forearm compartment pressures in a Nigerian population.

PURPOSE: The forearm is prone to raised compartment pressure and it is the second most common site for compartment syndrome. The normal compartment pressure of the forearm should be known and serve as a benchmark for the diagnosis of acute and chronic compartment syndrome. This study was aimed to determine the normal compartment pressures of the forearm using a digital compartment pressure monitor. METHODS: This was a prospective hospital-based study of the uninjured forearm in 30 patients, who presented with closed unilateral forearm fracture at the accident and emergency department of a tertiary health care facility, between June 2012 and December 2013. Approval was sought and obtained from institutions ethical committee. An 18 gauge bevelled-tip needle, attached to a Compass TM digital compartment pressure monitor made by Mirador USA, was used to measure the pressures in the compartments of the forearm. Data obtained were analysed using the Stata 12. Significance was determined at p < 0.05. RESULTS: The mean age was 38.3 ± 18.3 years with male-to-female ratio of 2.3:1. The pressures in the volar compartment of the forearm ranged from 1 to 8 mmHg with a mean ± SD compartment pressure of 4.7 ± 1.5 mmHg. In the dorsal compartment the pressure ranged from 2 to 8 mmHg with a mean ± SD of 4.9 ± 1.7 mmHg SD, while the lateral compartment measurement ranged between 1 and 5 mmHg with a mean ± SD of 3.6 ± 1.1 mmHg. There was significant positive correlation (p < 0.01) between the compartment pressures in the volar, dorsal, and lateral compartments. CONCLUSION: The normal compartment pressure for forearm is 4.4 ± 1.6 mmHg and ranged from 1 to 8 mmHg from this study in our environment. This will serve as reference value when forearm compartment pressure is being measured.

Assessment of Forearm Rotational Control Using 4 Upper Extremity Immobilization Constructs.

BACKGROUND: Forearm immobilization techniques are commonly used to manage distal radius, scaphoid, and metacarpal fractures. The purpose of our study was to compare the degree of rotational immobilization provided by a sugar-tong splint (STS), short arm cast (SAC), Munster cast (MC), and long arm cast (LAC) at the level of the distal radioulnar joint (DRUJ), carpus, and metacarpals. METHODS: Seven cadaveric upper extremity specimens were mounted to a custom jig with the ulnohumeral joint fixated in 90° of flexion. Supination and pronation were unrestricted. K-wires were placed in the distal radius, scaphoid, and metacarpals using fluoroscopic guidance to measure the total arc of rotation referenced to the ulnar ex-fix pin. Baseline measurements followed by sequential immobilization with well-molded STS, SAC, MC, and LAC were obtained with 1.25, 2.5, and 3.75 ft-lb of supination and pronation force directed through the metacarpal K-wire. Each condition was tested 3 times. Digital photographs were taken perpendicular to the ulnar axis to analyze the total arc of motion. RESULTS: The most effective constructs from least to greatest allowed rotational arcs were LAC, MC, SAC, and STS. Above-elbow constructs (MC, LAC) demonstrated superior immobilization compared with below-elbow constructs (SAC) ( P < .001). Circumferential constructs (SAC, MC, LAC) were superior to the noncircumferential construct (STS) ( P < .001). There were no significant differences between the MC and LAC in all conditions tested. CONCLUSIONS: Both circumferential and proximally extended immobilization independently improved rotational control of the wrist. However, extending immobilization proximal to the epicondyles did not confer additional stability.

Assessment of lower arm movements using one inertial sensor.

Reduction of the number of sensors needed to evaluate arm movements, makes a system for the assessment of human body movements more suitable for clinical practice and daily life assessments. In this study, we propose an algorithm to reconstruct lower arm orientation, velocity and position, based on a sensing system which consists of only one inertial measurement unit (IMU) to the forearm. Lower arm movements were reconstructed using a single IMU and assuming that within a measurement there are moments without arm movements. The proposed algorithm, together with a single IMU attached to the forearm, may be used to evaluate lower arm movements during clinical assessments or functional tasks. In this pilot study, reconstructed quantities were compared with an optical reference system. The limits of agreement in the magnitude of the orientation vector and the norm of the velocity vectors are respectively 4.2 deg (normalized, 5.2 percent) and 7.1 cm/s (normalized, 5.8 percent). The limit of agreement of the difference between the reconstructed positions of both sensing systems were relatively greater 7.7 cm (normalized, 16.8 percent).

Forearm and Hand Function after Radial Artery Harvest for Coronary Artery Bypass Grafting: Subjective Patients' Assessment.

BACKGROUND: As arterial myocardial revascularization is proved to provide great results, radial artery use as a graft and its consequences remain an important issue. OBJECTIVES: The aim of the study was to evaluate how patients assess their forearm and hand function after radial artery harvest for coronary artery bypass grafting (CABG). METHODS: 50 patients (mean age 52.2 ± 7.4 years) who underwent CABG at least 6 months (median follow up 11.75 months) earlier filled in a questionnaire concerning hand and forearm efficiency and discomfort. RESULTS: The global efficiency of the operated upper extremity was scored mean 8.87 ± 1.26 points on a 10-point scale and it was worse in patients who noticed at least one sort of disorder than in patients with no problems (8.6 ± 1.4 versus 9.4 ± 0.7 points; P = .04). Paresthesias were the most often reported disorders; 21 patients felt some tingling and/or numbness, but in only 14 (28%) could the symptoms be considered as related to the operation. 20 patients (40%) declared that they felt some scar-related discomfort. Reduced grip strength and excessive hand fatigue were reported by 20% and 10% of patients, respectively. None of those interviewed answered that symptoms reported affected his or her life activity on any level. CONCLUSION: The hand and forearm efficiency after radial artery harvest for CABG was highly evaluated by the majority of patients. Despite the fact that many patients reported some surgery-related problems, they did not notice extremity dysfunction that could limit their life activity.

Is softcast (3M) strong enough for potentially unstable paediatric forearm fractures?

INTRODUCTION: The majority of paediatric forearm fractures are treated using a circumferential splint, with prior manipulation as necessary. Plaster of Paris is often chosen for its ease of application, cost and proven reliability. Softcast is an alternative, providing a comfortable and water-resistant splint that can be removed without a plaster saw, and is in widespread use for immobilising buckle fractures. Softcast has not been recommended for acute unstable fractures. We established whether a Softcast splint could provide sufficient mechanical stability to control an unstable paediatric forearm fracture. METHODS: A laboratory study was undertaken to compare the 3 point (kinking) and 4 point bending, and torsion loads to defined clinical failure points withstood by standardised 4-wrap POP compared to Softcast splints with 6-wrap, 4 wrap and reinforced 4-wrap configurations. RESULTS: The load at clinically relevant failure of a 6-wrap Softcast forearm splint was 504N in 4 point bending, 202N in 3 point bending (kinking), and 11Nm in torsion (equalling 30.4%, 26% and 42.2% of the equivalent values for a circumferential 4-wrap POP). The 6-wrap Softcast was however stronger in all modes than a fibreglass-reinforced Softcast splint (previously recommended for acute fractures). Furthermore, the load to failure in all modes exceeds that which can be exerted by body weight in many paediatric patients. Softcast demonstrated complete recovery of its original shape on unloading, whereas POP was permanently deformed. 6-wrap Softcast splints were 4% lighter than POP. CONCLUSION: A 6-wrap Softcast splint provides adequate mechanical stability and protection for paediatric patients up to approximately 20kg, avoiding high-risk activities. The primary risk is not of fracture angulation and loss of position, but temporary indentation of the splint, causing discomfort or pain. Considering its ease of removal, Softcast may be preferable for younger paediatric patients. Its cost may be offset by reducing the number and duration of hospital visits.

Body Segment Kinematics and Energy Expenditure in Active Videogames.

OBJECTIVE: Energy expenditure (EE) in active videogames (AVGs) is a component for assessing its benefit for cardiovascular health. Existing evidence suggests that AVGs are able to increase EE above rest and when compared with playing passive videogames. However, the association between body movement and EE remains unclear. Furthermore, for goal-directed game design, it is important to know the contribution of body segments to EE. This knowledge will help to acquire a certain level of exercise intensity during active gaming. Therefore, the purpose of this study was to determine the best predictors of EE from body segment energies, acceleration, and heart rate during different game situations. MATERIALS AND METHODS: EE and body segment movement of 17 subjects, aged 22.1 ± 2.5 years, were measured in two different AVGs. In randomized order, the subjects played a handheld-controlled Nintendo(®) Wii™ tennis (NWT) game and a whole body-controlled Sony EyeToy(®) waterfall (ETW) game. Body segment movement was analyzed using a three-dimensional motion capture system. From the video data, mean values of mechanical energy change and acceleration of 10 body segments were analyzed. RESULTS: Measured EE was significantly higher in ETW (7.8 ± 1.4 metabolic equivalents [METs]) than in NWT (3.4 ± 1.0 METs). The best prediction parameter for the more intense ETW game was the energy change of the right thigh and for the less intense hand-controlled NWT game was the energy change of the upper torso. Segment acceleration was less accurate in predicting EE. CONCLUSION: The best predictors of metabolic EE were the thighs and the upper torso in whole body and handheld-controlled games, respectively. Increasing movement of these body segments would lead to higher physical activity intensity during gaming, reducing sedentary behavior.

Developing and validating a self-report assessment tool for software biomechanics.

BACKGROUND: There are many effective methods for decreasing the likelihood of repetitive strain injury (RSI) for those who work at a computer in an office environment. This study is focused on the highly repetitive task of interpreting seismic data. The skilled geoscientists who perform this work are very well compensated, and their work is vital to the success of the oil company. However, RSIs are still occurring in situations where effective methods of mitigating injuries have been successfully implemented and this has been occurring very frequently for geoscientists. This suggests that there are other elements contributing to the development of these injuries and one element could be the software interaction design. However, it is difficult for software designers to determine this because most measures associated with muscle activity require expensive data collection methods. OBJECTIVE: This paper describes research conducted to determine if survey-based subjective measures might be used to assess the potential for RSI for software programs. METHODS: In laboratory and field settings, data were collected using three different survey instruments (NASA-Task Load Index, Latko's Busiest Hand Activity Level Scale, and the Borg CR10 Rating of Perceived Exertion Scale) and conventional measures of muscle activity (sEMG). Correlations between the surveys and muscle activity were then calculated. RESULTS: For both the laboratory and the field, people were able to provide reliable self-report information related to their muscle activity. However, the effect sizes were not large. CONCLUSIONS: These results suggest that self-report tools could be utilized to identify software interaction designs related associated with risks of RSI.

A cable-driven wrist robotic rehabilitator using a novel torque-field controller for human motion training.

Rehabilitation technologies have great potentials in assisted motion training for stroke patients. Considering that wrist motion plays an important role in arm dexterous manipulation of activities of daily living, this paper focuses on developing a cable-driven wrist robotic rehabilitator (CDWRR) for motion training or assistance to subjects with motor disabilities. The CDWRR utilizes the wrist skeletal joints and arm segments as the supporting structure and takes advantage of cable-driven parallel design to build the system, which brings the properties of flexibility, low-cost, and low-weight. The controller of the CDWRR is designed typically based on a virtual torque-field, which is to plan "assist-as-needed" torques for the spherical motion of wrist responding to the orientation deviation in wrist motion training. The torque-field controller can be customized to different levels of rehabilitation training requirements by tuning the field parameters. Additionally, a rapidly convergent parameter self-identification algorithm is developed to obtain the uncertain parameters automatically for the floating wearable structure of the CDWRR. Finally, experiments on a healthy subject are carried out to demonstrate the performance of the controller and the feasibility of the CDWRR on wrist motion training or assistance.

Wearable Sensors in Medical Education: Supporting Hand Hygiene Training with a Forearm EMG.

Lack of proper hand hygiene is a common source of hospital acquired infections. Training and evaluating efficiency in hand washing is therefore an important part of medical education. Here, we propose to use the Myo wearable armband to measure correctness of hand washing for mobile learning. Myo's sensors are designed in order to recognize the activity of the forearm, palm and fingers. Using signal processing and machine learning, the quality of the hand washing process can be estimated and used as evaluation in medical teaching. The project is in its initial phase, thus we present preliminary results and a vision of future development.

Radial head implant diameter: A biomechanical assessment of the forgotten dimension.

BACKGROUND: The effect of radial head implant length has been a subject of controversy, with the impact on clinical outcomes and forearm biomechanics being extensively studied. However, the impact of radial head diameter on forearm load transfer has not been examined. This study examined the influence of radial head implant diameter on forearm load transfer as measured by interosseous membrane tension and radiocapitellar joint contact characteristics. METHODS: An upper extremity simulator was utilized to study five cadaveric specimens with three different radial head implant diameters (-2mm, anatomically sized, +2mm). A load sensing device was woven into the fibers of the central band of the interosseous membrane to quantify its tension. An inter-positional pressure measurement sensor was used to quantify radiocapitellar joint contact force and area. Axial loads of 160N were applied to the forearm during forearm rotation with the elbow at 90° of flexion. FINDINGS: Changes to the radial head diameter did not change radiocapitellar contact force or area (P=0.4 and P=0.5 respectively). There was a linear relationship between radial head diameter and interosseous membrane tension; increasing radial head diameter increases the interosseous membrane tension (P=0.01). INTERPRETATION: Although radial head diameter was not found to alter radiocapitellar contact area or force, the interosseous membrane tension was impacted. After radial head arthroplasty, an increase in radial head implant diameter increases the interosseous membrane tension, with a potential for increased pain and stiffness. There is also a potential for increased proximal radioulnar joint contact pressures; resulting in stem loosening or radio-ulnar pain.

A motion artifact generation and assessment system for the rapid testing of surface biopotential electrodes.

Dry electrodes can reduce cost while increasing the usability and comfort of wearable monitoring systems. They are, however, susceptible to motion artifacts. The present electrode testing methods lack reliability and do not separate the factors that affect the motion artifact. In this paper, we introduce a first generation motion artifact generation and assessment system that generates the speed, amplitude, and pattern-wise programmable movement of the electrode. The system simultaneously measures electrode-skin impedance, the motion artifact, and one channel of an electrocardiogram that contains the motion artifact and monitors the mounting force applied to the electrode. We demonstrate the system by comparing the applied movement and the measured signals for electrode movements up to 6 mm and movement frequencies from 0.4 Hz to 4 Hz. Results show that the impedance change and surface potential are visually clearly related to the applied motion, with average correlations of 0.89 and 0.64, respectively. The applied force, electrode location, and electrode structure all affect the motion artifact. The setup enables the motion of the electrode to be accurately controlled. The system can be used as a precursor to the testing of integrated systems because it enables thorough, repeatable, and robust motion artifact studies. The system allows a deeper insight into motion artifacts and the interplay of the various factors that affect them.