MEC Symposium Conference Proceedings

Permanent URI for this collection

Since 1972, the Institute of Biomedical Engineering at the University of New Brunswick has been hosting the MEC Symposium in Fredericton, New Brunswick, Canada. Since 2002, the Symposium occurs tri-annually, incorporating all aspects of powered upper limb prosthetics. The Symposium is immediately preceded by courses and workshops geared toward clinicians.

The historical conference proceedings have been made available through the generosity of UNB and the Institute of Biomedical Engineering, through a partnership with Duke University and the Open Prosthetics Project, where a list of proceedings from MEC '02, MEC '05 and MEC '08 can be found.


Recent Submissions

Now showing 1 - 20 of 344
  • ItemOpen Access
    Using Computers To Make Outcome Measurement Easier: Introduction To The Software Version Of The Prosthetic Upper Extremity Functional Status Index (The PUFI)
    (1999) Wright, F. Virginia; Hubbard, Sheila; Jutai, Jeffery; Naumann, Stephen; Schuller, Reinhard
  • ItemOpen Access
    The War Amputations Of Canada: Addressing The Needs Of Canadian Amputees
    (1999) Fifield, Adele
    I lost a leg to cancer at the age of 13. I became a member of The War Amps Child Amputee Program, or CHAMP as it is better known, shortly theteafter. For the last 10 years I have worked with the War Amps and am presently its Director of the National Amputee Centre and Director of Prosthetics and Counselling. In that time, I have attended over a dozen prosthetic conferences to keep up-to-date on artificial limbs and to pass that information on to Canadian amputees. The War Amputations of Canada is a charitable organization that has been in mdstence for ovet 80 years and I will share with you an overview of our history and what we do.
  • ItemOpen Access
    The use of the Hilbert transforra in EMG Analysis
    (1999) Taffler, Sean; Kyberd, Peter J.
    The Fourier transform has traditionally been used for the detailed analysis of EMG signals. This has yielded many useful results, none more so than the descriptions of the energy produced at differing frequencies. This has been invaluable in the development of robust EMG controllers and the analysis of active or diseased muscle. Recently, Wavelet analysis has been applied to the study of EMG signals and it has provided additional insight into the underlying structure of the signal. Both these methods have drawbacks, the Fourier transform relies on analysis of complete wavelengths to describe a signal Wavelet analysis cannot resolve any event less than the length of the fundamental Wavelet. These factors manifest themselves as a smudging or broadening of the spectrum and therefore they lead to inprecissions in the results. Empirical Mode Decomposition (EMD) and the Hilbert Transform (HT) have been applied to analyse the the EMG signal. This is a method that is used extensively in the fields of seismology and meteorology and is now being applied to biological data. It is particularly good a resolving signals that are not based on continuous sinusoids. It has been used on EMGs to show that the energy in the signal is significant at frequencies up to 2KHz. The paper will present the results of a study of signals derived from a range of prosthesis users and non-users. The results from the Hilbert transform will be compared with results obtained using conventional methods of analysis.
  • ItemOpen Access
  • ItemOpen Access
  • ItemOpen Access
    The Use of Fuzzy Logic In the Processing Of Myoelectric Signals
    (1999) Taffler, Sean; Kyberd, Peter J.
    This paper describes the use of Fuzzy logic for the processing of EMG signals. This can increase the recognition rate and significantly reduce the number of computations required to generate an output. The initial placement of the Fuzzy sets was accomplished with the use of neural network techniques, these are not required for in the final system, only for setting up. The effectiveness of the features extracted from the EMG signals has been assessed using Principal Component Analysis (PCA) The developed system exhibits good generalisabilty but performs better when tuned to the intended user.
  • ItemOpen Access
    Teleassistance For Electronic Components In Rehabilitation Technology
    (1999) Davalli, A.; Sacchetti, R.; Ferrara, P.; Dietl, H.
  • ItemOpen Access
    The Development Of An Advanced Multi-Axis Myo-Prosthesis And Controller
    (1999) Light, C. M.; Chappell, P. H.
    Commercial myo-electrically controlled prostheses are currently single degree of fieedom devices with highly restrictive function. These artificial hands warrant high grip forces due to their planar pincer movement to ensure stable prehension, thereby inherently requiring precise and conscious effort on the part of the wearer to ensure optimum grip. The Southampton Hand has demonstrated the ability to devolve low-level user control to the hand prosthesis itself by the use of the Southampton Adaptive Manipulation Scheme. Until recently these multiple-axis prostheses have lacked clinical significance due to poor reliability and user-oriented design. The development of the latest device is centred on the hypothesis of enhancing stable piehension by increasing the adaptability of the prosthesis, whilst simultaneously minimising the necessary grip force. This is to be achieved by increasing the number of independent degrees of freedom of the device without compromising user-effort by utilising the Southampton hierarchical control system. Constraints such as modularity, low weight and power consumption are factors that have been adhered to throughout the design process. The six independent axes of the hand are controlled by a single microprocessor. The limiting factor in the advancement of artificial hands has frequently been the integration of technology to the device. Consequently several accurate sensing systems were implemented in this design to enable a more comprehensive control of the adaptable hand prosthesis.
  • ItemOpen Access
    Quantifying Impaired Hand Function In The Clinical Environment
    (1999) Light, C. M.; Chappell, P. H.; Kyberd, P. J.
    The Southampton Hand Assessment Procedure (SHAP) has been developed specifically to enable the broadbased evaluation of hand function irrespective of the disability, thereby allowing assessment of both natural and prosthetic hands. This technique enables a contextual result to be formed (relative to normal hand ftxnction), hence providing a quantifiable index of functionality rather than the more conventional subjective measures. The establishment of normative data trials and subsequent statistical analysis demonstrates the procedure to be both reliable and r epeatable. The procedure has been undergoing evaluation at hand rehabilitation and prosthetic fitting centres. The subject group consists of those with impaired natural hand fimction (ranging fiom traumatic injury to diseased joints), as well as unilateral amputees and those with congenital deficiencies ofthe upper limb. These initial cases have assisted in the refinement of the index of functionality thatresults fiom the procedure. The perceived hand fiinction of these case studies is presented in comparison with the SHAP results. Quantification of functionality is of clinical importance to allow surgeons and therapists to monitor rehabilitation, and preliminary results suggest that the Southampton Hand Assessment Procedure provides a critical contribution to this process.
  • ItemOpen Access
    Prosthetic Management Of A Child With A Phocomelic Deficiency
    (1999) Bauer-Hume, Heidi; Wierzba, Sol; Woo, Anne; Bishop, John
    The subject of this case study is an 8 year old girl who has a phocomelic deficiency of her left uppet extremity. Her phocomelic hand consists of 3 digits including a thumb and has limited strength and range of motion. She also has an unusually pronainent and mobile "spilced" clavicle and no scapula. All other limbs and systems are unaffected and she is a bright, energetic little girl.
  • ItemOpen Access
    Programmable Control: Clinical Experience At Bloorview MacMillan Centre
    (1999) Kurtz, Isaac; Heim, Winfried; Bauer-Hume, Heidi; Hubbard, Sheila; Ramdial, Sandra
    Advances in microprocessor technology in recent years have led to the introduction of programmable control systems for powered prosthetics. These systems allow amputees to try a variety of control schemes and choose the one that suits them best. Prosthetists, no longer limited to preprogrammed control schemes, can devise new schemes that are suited for the amputee's individual needs. Over the past few years, Bloorview MacMillan Centre has fit approximately 20 clients with programmable control systems. A retrospective analysis of this group, which includes amputation levels fiom below-elbow to shoulder disarticulation, demonstrates the benefits this approach. The benefits fall into four general categories: 1) evolution of the control system as the user's needs and abilities change, 2) the amputee's ability to choose their own preferred strategy, 3) accommodation of abnormal and noisy signals and 4) ability to accommodate high-level amputees. This paper will summarize our clinical experience with programmable control. Case studies illustrating this approach and its various benefits will be presented.
  • ItemOpen Access
    New Clinically-Useful Control Strategies Made Possible By The Varigrip II Multi-Device Controller
    (1999) Wallace, Craig; Williams, T. Walley, III
    The VariGrip II Controller can operate up to three variable speed motors. For inputs it uses two, three, or four variable voltages and one on-off switch. This makes a large number of control strategies available, but not all are clinically useful. To date the most popular controls have used two myoelectrodes to control two or three devices. The controller has been used with the two VASI elbows and the Hosmer and Boston elbows to solve clinical problems that were heretofore intractable. The system also permits proportional control of two-motor devices such as the Bock 2000 hands, the Steeper Gripper, and the Centri UltraLite hand. We will discuss a number of the strategies that have proven clinically useful.
  • ItemOpen Access
    Optimal Fixed Wrist Alignment For Below-Elbow, Powered, Prosthetic Hands
    (1999) Landry, J.; Biden, E. N.
    The typical prosthetic wrist has a limited range of motion. Although a rotating device may be used for pronation/supination, flexion/extension and radial/ulnar deviation generally are set in a fixed alignment by the prosthetist. The prosthesis wearer compensates for the lack of wrist motion with abnormally large motions of the shoulder and elbow. This may give an awkward appearance, and also increase the risk of joint injury. The goal of the prosthetist is to choose an alignment that reduces these compensating motions. Unfortunately, people disagree as to what the optimal alignment is. The goal of this study is to quantify the resulting arm motions for various alignments, and determine which alignments allow near-normal motion. This study examined ten subjects per forming tluee activities of daily living (ADLs). The ADLs were 1) drinking ftom a cup, 2) eating with a spoon and 3) eating a sandwich. The subjects were all normally-limbed, so hand and wrist splints were worn to imitate a powered prosthesis. Five different alignments were tested using five wrist splint settings (0-10 degrees) and "normal" condition was tested with no wrist splint worn. Motions were recorded using a WON' 140 motion analysis system The height to which the subject raised his/her elbow was used as a measurement of shoulder range of motion. Alignments were considered "acceptable" if they resulted in the elbow-being lifted less than or only slightly greater than "normal". FINAL PAPER NOT RECEIVED AT PRESS TIME
  • ItemOpen Access
    Natural Control Of Key Grip And Precision Grip Movements For A Myoelectric Prostheses
    (1999) Santa-Cruz, M. C.; Riso, R. R.; Lange, B.; Sepulveda, F.
    Hand prosthesis function is augmented when the user canemploy lateral grasp as well as traditional palmer grasp. Our goal in this investigation was to enable the below-elbow (BE) prostheses user to switch between and use these grasp modes in a natural and reliable manner. We recorded the EMG from residual muscles (flexor dig; ext dig; flex pollicis longus, ext pollicis longus) involved in these grasp activities in an adult subject with below elbow (BE) amputation while she contracted her residual forearm muscles to mimic computer animations of different hand movements. To reduce crosstalk between the recordings from seperate muscles, and to enhance the stability of the recording interface over the 30-day duration of the experimental sessions, we used chronically implanted percutaneous coiled wire electrodes implanted for 30 days (12 one-day sessions). Artificial Neural Network (ANN) pattern recognition techniques were used to extract voluntary command signals from the EMG signals. The mean absolute value (MAV) of the EMG signals was selected as a feature for training multilayer perceptions. Initially, we trained ANNs having 5 hidden neurons using data from the 10' and 12 session individually (3 training sessions each). Three additional ANNs (sizes 4:7:4, 4:8:4, 4:9:4) were designed and trained (3 training sessions each) with combined data from experimental sessions 10 and 12. Subsequently, we separately tested the performance of these ANNs with data from the 9, 10 and 12 experimental sessions. While the results showed that data from different experimental days were substantially consistent, more reliable recognition of the grasp mode from any arbitrary test sample (i .e.. taken from test sessions 9,10 or 12), was achieved when we used an ANN that was trained with representative samples from more than a single experimental day (e.g. using 10th and 12th experimental days data for training). This produced mean rates of recognition (averaged over the results from the three ANN training sessions with network size 4:8:4) of 97 6% key grip closing, 83 3% keygrip opening, 85.7% precision grip closing, 96.4% precision grip opening, for the combined evaluation data from all test sets. We conclude that intuitive operator selection, between key grip and precision grip modalities, is feasible for cases of BE amputation using recorded myoelectric signals.
  • ItemOpen Access
    Microframe Interface Design For High Level Myoelectr1c Prostheses
    (1999) Miguelez, John M.
    The provision of a myoelectric prosthesis for high level upper extremity amputees requires consideration of a myriad of factors. Although state-of-the-art componentty can dramatically effect the outcome, other factors left unaddressed can negate any advantages that new technology canoffer. Many individrials fit with a prosthesis fiom the humeral neck level and higher often complain that the weight of the prosthesis, heat build-up while wearing the prosthesis, lack of stability, difficulty in independent donning, and reduced control of terminal device while in certain planes and body positions have resulted in reduced wearing times and in many cases discontinuation of prosthetic use all together. Of course, the factors listed above that lead to reduced wear and in some cases discontinuation are not comprehensive, but do overwhelmingly categorize the responses of over 250 high level amputees polled across the United States between 1993-1999. Although a panacea does not exist to completely eliminate the above factors that lead to discontinuation, substantial success at addressing these concerns can be found in the use of an interface design. Typical interface designs for high level amputees can generally be divided into three classes: 1) "Bucket Interface Style" that completely cover s the effected shoulder and torso often to the midline. The major disadvantage of this style is overheating of the wearer due to excessive interface to skin coverage. 2)"Modified Bucket Style" which encompasses the basicdesign of the "Bucket Interface Design" as it completely encapsulates the shoulder girdle but does not extend to the midline or inferiorly to capture a majority of the torso. This design has partial success in the reduction of heat build up experienced by the wearer, but often results in poor stability and lack of skin to electrode contact whichis manifested in poor terminal device control in certain planes and body positions. Additionally, auxiliary harnessing is required for this design which can have a negative impact on independent donning. 3)"Sander Frame Design" which involves the use of aluminum struts to reduce heat build up and provide acceptable stability and dorming effort. This design has not been universally adopted in the United States due to high degree of fabrication time and skill required. The purpose ofthis paper is to detail the Microframe Interface Design, a more effective alternative to the three current interface designs for high level myoelectric prostheses. FINAL PAPER NOT RECEIVED AT PRESS TIME
  • ItemOpen Access
    Magnetic Resonance Imaging of Congenitally Deficient Upper Limbs
    (1999) Farry, Kristin A.; Kramer, Larry A.; Gupta, Radihka; Atkins, Diane J.; Donovan, William H.
    Knowledge of the anatomic location, size, and contractility of muscles within a person's congenitally deficient upper limb is useful in prescribing and fitting a myoelectric prosthesis. In 1998, at University of Texas' Hermann Hospital, magnetic resonance imaging (MM) was used to image both arms of five volunteers with congenital unilateral below elbow upper limb deficiences. Imaging both arms of each subject enables a direct comparison of normal and residual limb anatomy. The volunteers included one adult and four teenagers. This paper summarizes findings on residual versus sound side musculature size, limb size, and selected residual limb features.
  • ItemOpen Access
    Low Level Response Of Bock And Steeper Electrodes
    (1999) Wallace, Craig; Williams, T. Walley, III; Taneja, Nathan
    For many years myoelectric fittings have been limited by the need for signals of at least 2011V when using convenient in-socket myoelectrode-amplifiers. With the introduction of the Bloorview-MacMillan MyoMicro technology, the controller is able to further amplify the patient myosignal. To evaluate the Bock 13E125 and Steeper Electrodes for providing suitable signals for control in the region below 20uV, both electrodes were tested at each gain setting. The Bock electrode gives the best signals in the 1 to 5uV range while the Steeper electrode is less sensitive. With suitable downstream amplification, both electrodes will provide proportional control with signals of 0-10uV.
  • ItemOpen Access
    Forequarter Amputation: Self Suspending Shoulder Cap
    (1999) Allen, D.; Dykes, W. G.; Martin, C.
  • ItemOpen Access
    Forequarter Prosthesis With Interchangeable Elbow, Forearm, And Hand
    (1999) Lipschutz, Robert D.
    Fitting of individuals with forequarter amputations is often a challenging and fruitless effort. In order to provide optimum function for the patient, it is necessary to fit these individuals with either externally powered prostheses or hybrid prosthetic designs. These prostheses are often times heavy and bulky and are not accepted by the patients for full time wear. There exists another population of individuals with forequarter amputations that are more interested in the cosmetic restoration of the prosthesis rather than its functional capabilities. Passive prostheses are typically fabricated for these patients in order to fulfill their particular desire. In an effort to increase acceptance and wearing time, the prosthetic design being discussed in this paper is an attempt to meet both criteria: provide function and acceptable cosmetics. By utilizing existing components, this prosthetic design enables the user to readily switch from a heavier, externally poweted prosthesis to a lightweight, passive prosthesis.
  • ItemOpen Access
    Fitting The Humeral Level Brachial Plexus Amputee With Externally Powered Myoelectric Control
    (1999) Stevens, Gordon; Farnsworth, Troy
    Brachial plexus injuries present unique challenges to both the patient and prosthetist, The brachial plexus injury can be classified in many categories: complete or incomplete lesion, with either an intact or amputated limb as a result of the injury. The intact yet flail limb presents with lack of sensation, shoulder subluxation, severe pain, and is often subjected to unintentional burns and cuts. Many brachial plexus patients with an intact limb elect to undergo limb amputation to reduce complications or improve function with prosthetic fitting options. Unforttmately, some patients continue to experience similar post-amputation complications. Fusion of the shoulder joint is a surgical option in an attempt to decrease pain and reduce shoulder subluxation. This procedure may be performed before, after, or in association with amputation of the extremity.