Cheryl Metcalf

Markerless Motion Capture and Measurement of Hand Kinematics: Validation and Application to Home-Based Upper Limb Rehabilitation

Dynamic movements of the hand, fingers, and thumb are difficult to measure due to the versatility and complexity of movement inherent in function. An innovative approach to measuring hand kinematics is proposed and validated. The proposed system utilizes the Microsoft Kinect and goes beyond gesture recognition to develop a validated measurement technique of finger kinematics. The proposed system adopted landmark definition (validated through ground truth estimation against assessors) and grip classification algorithms, including kinematic definitions (validated against a laboratory-based motion capture system). The results of the validation show 78% accuracy when identifying specific markerless landmarks. In addition, comparative data with a previously validated kinematic measurement technique show accuracy of MCP ± 10° (average absolute error (AAE) = 2.4°), PIP ± 12° (AAE = 4.8°), and DIP ± 11° (AAE = 4.8°). These results are notably better than clinically based alternative manual measurement techniques. The ability to measure hand movements, and therefore functional dexterity, without interfering with underlying composite movements, is the paramount objective to any bespoke measurement system. The proposed system is the first validated markerless measurement system using the Microsoft Kinect that is capable of measuring finger joint kinematics. It is suitable for home-based motion capture for the hand and, therefore, achieves this objective.

Validation and Application of a Computational Model for Wrist and Hand Movements Using Surface Markers

A kinematic model is presented based on surface marker placement generating wrist, metacarpal arch, fingers and thumb movements. Standard calculations are used throughout the model and then applied to the specified marker placement. A static trial involving eight unimpaired participants was carried out to assess inter-rater reliability. The standard deviations across the data were comparable to manual goniometers. In addition, a test-retest trial of ten unimpaired participants is also reported to illustrate the variability of movement at the wrist joint, metacarpal arch, and index finger as an example of model output when repeating the same task many times. Light and heavyweight versions of the tasks are assessed and characteristics of individual movement strategies presented. The participant trial showed moderate correlation in radial/ulnar deviation of the wrist (r = 0.65), and strong correlation in both metacarpal arch joints (r = 0.75 and r = 0.85), the MCP (r = 0.79), and PIP (r = 0.87) joints of the index finger. The results indicate that individuals use repeated strategies of movement when lifting light and heavyweight versions of the same object, but showed no obvious repeated pattern of movement across the population.

Case studies to Demonstrate the Range of Applications of the Southampton Hand Assessment Procedure.

The Southampton Hand Assessment Procedure (SHAP) was devised to assess quantitatively the functional range of injured and healthy adult hands. It was designed to be a practical tool for use in a busy clinical setting; thus, it was made simple to use and easy to interpret. This paper describes four examples of its use: before and after a surgical procedure, to observe the impact of an injury, use with prostheses, and during recovery following a fracture. The cases show that the SHAP is capable of monitoring progress and recovery, identifying functional abilities in prosthetic hands and comparing the capabilities of different groups of injuries.

Proximal interphalangeal joint replacement in patients with arthritis of the hand: A meta-analysis

We systematically reviewed all the evidence published in the English language on proximal interphalangeal joint (PIPJ) replacement, to determine its effectiveness on the function of the hand and the associated post-operative complications. Original studies were selected if they reported clinical outcome with a minimum of one years follow-up. Quality was assessed using the Cowley systematic review criteria modified for finger-joint replacements. Of 319 articles identified, only five were adequately reported according to our quality criteria; there were no randomised controlled trials. PIPJ replacements had a substantial effect size on hand pain of -23.2 (95% confidence interval (CI) -27.3 to -19.1) and grip strength 1.2 (95% CI -10.7 to 13.1), and a small effect on range of movement 0.2 (95% CI -0.4 to 0.8). A dorsal approach was most successful. Post-operative loosening occurred in 10% (95% CI 3 to 30) of ceramic and 12.5% (95% CI 7 to 21) of pyrocarbon replacements. Post-operative complications occurred in 27.8% (95% CI 20 to 37). We conclude that the effectiveness of PIPJ replacement has not been established. Small observational case studies and short-term follow-up, together with insufficient reporting of patient data, functional outcomes and complications, limit the value of current evidence. We recommend that a defined core set of patients, surgical and outcome data for this intervention be routinely and systematically collected within the framework of a joint registry.

Methodologies to assess muscle co-contraction during gait in people with neurological impairment – A systematic literature review

PURPOSE To review the methodologies used to assess muscle co-contraction (MCo) with surface electromyography (sEMG) during gait in people with neurological impairment. METHODS The Scopus (1995-2013), Web of Science (1970-2013), PubMed (1948-2013) and B-on (1999-2013) databases were searched. Articles were included when sEMG was used to assess MCo during gait in people with impairment due to central nervous system disorders (CNS). RESULTS Nineteen articles met the inclusion criteria and most studied people with cerebral palsy and stroke. No consensus was identified for gait assessment protocols (surfaces, speed, distance), sEMG acquisition (electrodes position), analysis of sEMG data (filters, normalisation techniques) and quantification of MCo (agonist-antagonist linear envelopes overlapping or agonist-antagonist overlapping periods of muscles activity, onset delimited). CONCLUSION Given the wide range of methodologies employed, it is not possible to recommend the most appropriate for assessing MCo. Researchers should adopt recognized standards in future work. This is needed before consensus about the role that MCo plays in gait impairment in neurological diseases and its potential as a target for gait rehabilitation can be determined.

A narrative review on haptic devices: relating the physiology and psychophysical properties of the hand to devices for rehabilitation in central nervous system disorders

Purpose: This article provides rehabilitation professionals and engineers with a theoretical and pragmatic rationale for the inclusion of haptic feedback in the rehabilitation of central nervous system disorders affecting the hand. Method: A narrative review of haptic devices used in sensorimotor hand rehabilitation was undertaken. Presented papers were selected to outline and clarify the underlying somatosensory mechanisms underpinning these technologies and provide exemplars of the evidence to date. Results: Haptic devices provide kinaesthetic and/or tactile stimulation. Kinaesthetic haptics are beginning to be incorporated in central nervous system rehabilitation; however, there has been limited development of tactile haptics. Clinical research in haptic rehabilitation of the hand is embryonic but initial findings indicate potential clinical benefit. Conclusions: Haptic rehabilitation offers the potential to advance sensorimotor hand rehabilitation but both scientific and pragmatic developments are needed to ensure that its potential is realized. Implications for Rehabilitation The current lack of emphasis on somatosensory rehabilitation may contribute to poor hand recovery in patients with central nervous system pathology. Haptic technologies have the potential to improve sensation and sensory motor integration in neurological conditions. An underlying theoretical rationale is provided for the design and clinical use of haptic technologies in neuro-rehabilitation of the hand.

Complex hand dexterity: a review of biomechanical methods for measuring musical performance

Complex hand dexterity is fundamental to our interactions with the physical, social, and cultural environment. Dexterity can be an expression of creativity and precision in a range of activities, including musical performance. Little is understood about complex hand dexterity or how virtuoso expertise is acquired, due to the versatility of movement combinations available to complete any given task. This has historically limited progress of the field because of difficulties in measuring movements of the hand. Recent developments in methods of motion capture and analysis mean it is now possible to explore the intricate movements of the hand and fingers. These methods allow us insights into the neurophysiological mechanisms underpinning complex hand dexterity and motor learning. They also allow investigation into the key factors that contribute to injury, recovery and functional compensation. The application of such analytical techniques within musical performance provides a multidisciplinary framework for purposeful investigation into the process of learning and skill acquisition in instrumental performance. These highly skilled manual and cognitive tasks present the ultimate achievement in complex hand dexterity. This paper will review methods of assessing instrumental performance in music, focusing specifically on biomechanical measurement and the associated technical challenges faced when measuring highly dexterous activities.

Changes in Hand Function with Age and Normative Unimpaired Scores when Measured with the Southampton Hand Assessment Procedure

Assessment of limitations in hand function due to impairment is commonplace in clinical practice and clinical research. When assessing impairment, it is useful to have an understanding of what comparative results an aged-match unimpaired participant population would generate and how the natural effects of an increase in age have on these results. Using the Southampton Hand Assessment Procedure (SHAP), this study assessed dominant hand function of 95 unimpaired participants between the ages of 18–75 years. The results extended available data from previous research and showed that the average SHAP score was 98 (± 3.3). The results indicate that there is a natural decline in hand function after the age of 65 years (p <0.001), which concurs with previously published studies using other assessments.

A systematic review of the key factors affecting tissue viability and rehabilitation outcomes of the residual limb in lower extremity traumatic amputees

Most traumatic lower limb amputees ambulate using a prosthetic limb. Comfort, appearance of the missing limb and function are confirmed as being important during rehabilitation post-amputation. Emerging evidence suggests that impaired tissue viability of the stump affects rehabilitation and thus clinical ability to provide optimum care. The primary objective of this systematic review was to identify key factors relating to tissue viability of the residual limb in lower extremity traumatic amputees. A secondary objective was to identify factors that affect rehabilitation post-amputation. In total, 218 studies were assessed; 37 met pre-determined criteria. Studies were classified according to the WHO ICF framework and the NHMRC level of evidence. Five key themes emerged; Prosthetic Fit; The Residuum; Quality of Life; Amputee Care and Prosthetic Use. The evidence indicates that high frequencies of skin problems affecting tissue viability within this population are inherently linked to intolerance of the prosthesis. Stump integrity, amputee care regimen and pain were also identified as impacting on quality of life, affecting rehabilitation and the ability to become independently mobile. Levels of evidence within all studies were low and indicative of the majority being non-randomised cohort studies or case-control studies. As there are a limited number of interventional studies, further development of robust outcome measures, clinical trials and prospective studies are of utmost importance to unravel the links between tissue viability and the other key factors. This will inform clinical management strategies and help develop targeted therapies and care pathways.

Modified Kinematic Technique for Measuring Pathological Hyperextension and Hypermobility of the Interphalangeal Joints

Dynamic finger joint motion is difficult to measure using optical motion analysis techniques due to the limited surface area allowed for adequate marker placement. This paper describes an extension of a previously validated kinematic measurement technique using a reduced surface marker set and outlines the required calculations based on a specific surface marker placement to calculate flexion/extension and hyperextension of the metacarpophalangeal, proximal interphalangeal, and distal interphalangeal joints. The modified technique has been assessed for accuracy using a series of static reference frames (absolute residual error = ±3.7°, cross correlation between new method and reference frames; r = 0.99). The method was then applied to a small group of participants with rheumatoid arthritis (seven females, one male; mean age = 62.8 years ± 12.04) and illustrated congruent strategies of movement for a participant and a large range of finger joint movement over the sample (5.8-71.1°, smallest to largest active range of motion). This method used alongside the previous paper provides a comprehensive, validated method for calculating 3-D wrist, hand, fingers, and thumb kinematics to date and provides a valuable measurement tool for clinical research.