Effect of two adjacent muscles of flexor and extensor on finger pinch and hand grip force

Hand grip force and motion pattern classification using bio signal such as Electromyogram (EMG) has been very important in current studies. EMG based pattern classification has gain the utmost consideration especially in the commercial prostheses. Developing an intuitive hand control with fast response both in time and space are the major challenges. These challenges are due to the lack of information gathered from adjacent muscles. The study of adjacent muscles is crucially needed as it will allow to provide optimised hand grip and motion pattern classification without redundancy in the use of muscle information. The main aim of this paper is to investigate the effect of two adjacent flexor muscles; flexor digitorum superficial (FDS) and flexor carpi radialis (FCR), two adjacent extensor muscles: extensor carpi radialis longus (ECRL) and extensor digitorum communis (EDC) providing the perspective view of individual muscle performance compared to their adjacent muscle with respect to finger pinch and hand grip force. Practical classification results prove the significance of the study, both adjacent muscles perform almost similar with approximately 95% of similarities across different subjects. The results achieved lead to the conclusion, that the use of adjacent muscles can be reduced to only single muscle channel providing an optimised data for pattern recognition or classification

Influence of Force-Length Relationship and Task-Specific Constraints on Finger Force-Generating Capacities

Grip strength loss in extended and flexed wrist postures has been explained by reduced force-generating capacities of extrinsic finger flexor resulting from non-optimal length, owing to the force-length relationship. Recent works suggested that other muscles, especially wrist extensors, participate in this grip strength loss. The objective of this study was to clarify the role of the force-length relationship in finger force production. 18 participants performed maximal isometric finger force production during pinch grip (Pinch) and four-finger pressing (Press) tasks in four different wrist postures (extended, flexed, neutral, spontaneous). The maximum finger force (MFF), finger and wrist joint angles, as well as activation of four muscles were determined using dynamometry, motion capture, and electromyography. The force and length of the four muscles were estimated from joint angles and muscle activation using a musculoskeletal model. MFF decreased for flexed wrist during Pinch but remained stable across wrist postures during Press. The results suggested that the loss of pinch grip force in deviated wrist posture is partially related to force-length relationship of finger extensors. In opposition, MFF during Press was not influenced by the modulation of muscle capacities but was probably first limited by mechanical and neural factors related to finger interdependenceComment: Annals of Biomedical Engineering, 202

Hand motion pattern recognition analysis of forearm muscle using MMG signals

Surface Mechanomyography (MMG) is the recording of mechanical activity of muscle tissue. MMG measures the mechanical signal (vibration of muscle) that generated from the muscles during contraction or relaxation action. It is widely used in various fields such as medical diagnosis, rehabilitation purpose and engineering applications. The main purpose of this research is to identify the hand gesture movement via VMG sensor (TSD250A) and classify them using Linear Discriminant Analysis (LDA). There are four channels MMG signal placed into adjacent muscles which PL-FCU and ED-ECU. The features used to feed the classifier to determine accuracy are mean absolute value, standard deviation, variance and root mean square. Most of subjects gave similar range of MMG signal of extraction values because of the adjacent muscle. The average accuracy of LDA is approximately 87.50% for the eight subjects. The finding of the result shows, MMG signal of adjacent muscle can affect the classification accuracy of the classifier

Limits to temporal synchronization in fundamental hand and finger actions

Coordinated movement is critical not only to sports technique and performance but to daily living and as such represents a fundamental area of research. Coordination requires being able to produce the right actions at the right time and has to incorporate perception, cognition, and forceful neuro-muscular interaction with the environment. Coordinated movements of the hands and fingers are some of the most complex activities undertaken where continuous learning and adaptation take place, but the temporal variability of the most basic movement components is still unknown. This thesis investigates the extent of temporal variability in the execution of four different simple hand and finger coordination tasks, with the purpose to find the various intrinsic temporal variability which limit the ability to coordinate the hands in space and time. Study one showed that in a synchronized bi-lateral two finger tapping test (<<1 cm movement to target) the best participant had a temporaltiming variability of 4.8 ms whereas the largest time variability could be as high as 24.8 ms. No obvious improvement was found after transfer practice, whereas the average time variability for asynchronized tapping decreased from 62.1 ms to 30.3 ms after instructed practice indicating a likely change in task grouping. Study two showed that in a unilateral thumb-index finger pinch and release test, the largest mean timing variability was 12 ms for pinching irrespective of performing the task in a slow alert manner or at a faster speed. However, the mean temporal variability for release was only 6.3 ms when the task was performed in a more alert manner and indicates that release is more accurately controlled temporally than grip. Study three suggested that in a unilateral sagittal plane throwing action of the lower arm and hand, that elbow and wrist coordination for dynamic index finger tip location was better with a radial-ulnar deviation, darts-type, throwing action than a wrist flexor-extensor type action, basketball free throw type action (the mean variability was 37.5 ms and 27.2 ms, respectively). Study four compared the variability in bi-lateral finger tapping between voluntary tapping and involuntary finger contraction tapping. Electrically stimulated neural contractions had significantly lower force onset variability than voluntary or direct magnetic stimulation of muscles (6 ms, 9.5 ms, and 10.3 ms for electrically stimulated, voluntary and Transcranial Magnetic Stimulation stimulated contraction). This work provides a comprehensive analysis of the temporal variability in various fundamental digital movement tasks that can aid with the understanding of basic human coordination in sporting, daily living and clinical areas

Surface Electromyographic (sEMG) Transduction of Hand Joint Angles for Human Interfacing Devices (HID)

This is an investigation of the use of surface electromyography (sEMG) as a tool to improve human interfacing devices (HID) information bandwidth through the transduction of the fingertip workspace. It combines the work of Merletti et al and Jarque-Bou et al to design an open-source framework for Fingertip Workspace based Human Interfacing Devices (HID). In this framework, the fingertip workspace is defined as the system of forearm and hand muscle force through a tensor which describes hand anthropometry. The thesis discusses the electrophysiology of muscle tissue along with the anatomy and physiology of the arm in pursuit of optimizing sensor location, muscle force measurements, and viable command gestures. Algorithms for correlating sEMG to hand joint angle are investigated using MATLAB for both static and moving gestures. Seven sEMG spots and Fingertip Joint Angles recorded by Jarque Bou et al are investigated for the application of sEMG to Human Interfacing Devices (HID). Such technology is termed Gesture Computer Interfacing (GCI) and has been shown feasible through devices such as CTRL Labs interface, and models such as those of Sartori, Merletti, and Zhao. Muscles under sEMG spots in this dataset and the actions related to them are discussed, along with what muscles and hand actions are not visible within this dataset. Viable gestures for detection algorithms are discussed based on the muscles discerned to be visible in the dataset through intensity, spectral moment, power spectra, and coherence. Detection and isolation of such viable actions is fundamental to designing an EMG driven musculoskeletal model of the hand needed to facilitate GCI. Enveloping, spectral moment, power spectrum, and coherence analysis are applied to a Sollerman Hand Function Test sEMG dataset of twenty-two subjects performing 26 activities of living to differentiate pinching and grasping tasks. Pinches and grasps were found to cause very different activation patterns in sEMG spot 3 relating to flexion of digits I - V. Spectral moment was found to be less correlated with differentiation and provided information about the degree of object manipulation performed and extent of fatigue during each task. Coherence was shown to increase between flexors and extensors with intensity of task but was found corrupted by crosstalk with increasing intensity of muscular activation. Some spectral results correlated between finger flexor and extensor power spectra showed anticipatory coherence between the muscle groups at the end of object manipulation. An sEMG amplification system capable of capturing HD-sEMG with a bandwidth of 300 and 500 Hz at a sampling frequency of 2 kHz was designed for future work. The system was designed in ordinance with current IEEE research on sensor-electrode characteristics. Furthermore, discussion of solutions to open issues in HD-sEMG is provided. This work did not implement the designed wristband but serves as a literature review and open-source design using commercially available technologies

The development of an endoprosthesis for the metacarpophalangeal joint

Rheumatoid arthritis is a painful and debilitating disease which often afflicts the key joint of the hand, the metacarpophalangeal joint. In the worst cases the diseased joint has to be replaced with an artificial joint or prosthesis. The development of the Durham metacarpophalangeal prosthesis as it was taken from prototypes through to production samples, is described in this thesis. Testing of several Durham prostheses to over 70 million cycles has been carried out on a finger function simulator and consistent wear factors of the order of 0.4 x 10(^-) (^6)mm(^3)/Nm have been measured. These wear factors for the prosthesis were also significantly lower than any found previously. Production samples of the prosthesis have been manufactured together with appropriate surgical instrumentation. Tests of the prosthesis material, cross-linked polyethylene, rubbing against itself, have been undertaken on reciprocating pin on plate rigs and again show total wear factors of the order of 0.4 x lO(^-6)mm(^3)/Nm. Interestingly, it was found that pin wear was very much less than plate wear. The pin on plate tests were extended to include ultra-high molecular weight polyethylene (UHMWPE) rubbing against UHMWPE, as well as both polyethylenes against hard counterfaces and the results are reported. A new finger function simulator has been designed, manufactured and a validation test undertaken. Having written the necessary protocol, in conjunction with clinicians and the prosthesis manufacturer, ethical approval was obtained from the local research ethics committee and the Medical Devices Agency, to permit implantation of the prosthesis in human subjects. Lastly a hand strength measurement device for pre and post operation assessment of patients has been developed and manufactured

Rheumatoid Arthritis: Minimizing Deformity and Preserving Function in the Hand

Rheumatoid arthritis (RA) is a chronic disease of the synovial joints. The hand and wrist are the most commonly involved. The disease is characterized by pain, inflammation, limited range of motion, and destruction of bone and articular structures. In the later stages of RA, the person usually exhibits deformity of the affected joints. This can result in the inability to use the hand in a functional manner. Rheumatoid arthritis affects approximately one percent of the population. A person with RA usually has increased medical expenses. It is likely that the person will experience a loss of productivity and income due to disability. The mortality rate of individuals with RA is increased when compared to the general public. The purpose of this paper is to present an overview of RA including a history of the disease, prevalence, cost and work disability, and mortality that results from RA. In addition, the etiology and pathology of RA and common deformities of the wrist and hand that result from the disease process will be discussed. Physical therapy treatment of RA including patient education, splinting, surgery, exercise and modalities is reviewed. The physical therapist can be instrumental in educating the patient about their disease, appropriate joint protection and energy conservation techniques, and correct use of exercise and modalities to relieve pain and improve hand function

A finger function simulator and surface replacement prosthesis for the metacarpophalangeal joint

Joint replacement surgery in the treatment of arthritic disease is now commonplace and on the whole very successful. Research into the design and development of prostheses has made major advances since the 1940s resulting in complex devices for almost all articulating joints of the body. In this thesis, a programme of work to design and test a surface replacement prosthesis for the metacarpophalangeal joint is presented. The anatomy and kinematics of the MCP joint are discussed for both normal and abnormal joint function and, based on these considerations, the design of a new surface replacement prosthesis is described. Various materials are explored with respect to their biocompatibility, durability and ease of fabrication with special attention being paid to one material - a new cross linked ultra-high molecular weight polyethylene - which is tested for wear and assessed for durability in long-term prototype tests. A finger function simulator is detailed which was designed and developed during this research programme, and results of tests on bone replicas, Swanson Silastic implants and prototypes of the new design are presented. The simulator can be easily modified to accept any MCP joint prosthesis for bench testing. Finally the stress response of the prototype design is studied using finite element analysis and modifications to the implant design and bone preparation are suggested

Closed Proximal Phalangeal Fracture Management in Hand: An Outcome Analysis

INTRODUCTION : The proximal phalanx (PP) of the fingers is fractured more frequently than the middle or even distal phalanges. The problems of malunion, stiffness and sometimes associated soft tissue injuries increases the disability. The optimum treatment depends on fracture location, fracture geometry and fracture stability. The objective of the study was to analyse the treatment outcome in a series of closed proximal phalangeal fractures of the hand. MATERIALS AND METHODS : Fifty patients of proximal phalangeal fractures were enrolled from 2013 to 2015. The treatment modalities were broadly categorised into three groups, first group consisted of conservative treatment, second group consisted of open reduction and internal fixation. Third group consisted of external fixation. Out of fifty patients 29 patients were treated with ORIF. 12 patients were treated with closed reduction and immobilisation with POP and 9 patients were treated with external fixation. Total active range of motion, grip strength and pinch strength were used to assess the efficacy of conservative and surgical intervention of closed proximal phalangeal fractures of the hand. RESULTS : Average period of follow-up was 12 months. An excellent and good results good results were seen in second and first group of patients respectively. Complications are seen more in patients treated with POP. CONCLUSION : Conservative treatment is an inexpensive method, particularly suitable for stable fractures, and in patients who are poor candidates for surgery, surgical modalities have distinct advantage of stable fixation, but with added risk of digital stiffness. Both conservative and surgical modalities have good efficacy when used judiciously

Effects of Five Different Finger Rest Positions on Arm Muscle Activity During Scaling by Dental Hygiene Students

This study was conducted to determine the effects of five different finger rest positions, (fulcrums: opposite arch, standard intra-oral, basic extra-oral, cross arch and finger on finger) on the muscle activity of four forearm muscles, (extensor carpi radialis longus, flexor carpi ulnar is, biceps brachii and pronator teres) during a simulated periodontal scaling experience. A convenience sample of 32 consenting right handed senior dental hygiene students who met inclusion criteria participated. The 32 students had no history of injuries or disabilities to the right arm, wrist, or hand. Pre-test maximum voluntary isometric contraction (MVIC) scores were obtained prior to scaling. Using a 4 x 5 counterbalanced research design, each participant used a Premier Gracey 11/12 curet to scale up to one cc of artificial calculus from the mesiobuccal surfaces of first permanent molar typodont teeth (Nos. 3, 14, 19, and 30). Five different typodonts were set up for each participant with a different fulcrum randomly assigned for use on each typodont. Each participant scaled what calculus they could in a controlled, simulated situation for up to one minute per tooth using the randomly assigned fulcrum. While scaling, participants\u27 muscle activity was measured using surface electromyography (sEMG). Two-way ANOV A with repeated measures revealed no statistically significant interaction effect between area of the mouth scaled, muscle activity, and fulcrum used. Results revealed that following 20, one-minute scaling sessions using a hand instrument to remove artificial calculus, there was similar muscle activity generated. While scaling, forearm muscle activity was least when using the opposite arch fulcrum and most when using the cross arch fulcrum. Regardless of where scaling started more muscle activity occurred in the maxillary right quadrant and the least in the mandibular left. Based on the results, similar muscle activity is produced while scaling when using all of the five fulcrums tested in each area of the mouth. Clinicians appear to experience minimal ergonomic advantages in terms of fulcrum used and area of the mouth scaled during a simulated scaling experience. Characteristics of the patient may be more important when choosing a fulcrum than the amount of muscle activity generated