Showing papers in "Journal of Rehabilitation Research and Development in 1994"

Joint angle parameters in gait: reference data for normal subjects, 10-79 years of age

Abstract: In the laboratory, gait analysis is often completed with goniometry. In a previous article (Journal of Rehabilitation Research and Development, Vol. 30 No. 2), reference data for basic gait parameters were presented. The aim of this study was to provide such reference data for joint angle parameters. Two hundred and thirty-three healthy subjects (116 men and 117 women) 10-79 years of age, were entered into the study. The measurements were made in a gait laboratory with electrogoniometers with Lamoreaux type of exoskeleton. A series of reference tables for slow, normal and fast speed are presented. Means, standard deviations, coefficients of variation, 95% confidence intervals, and 95% prediction intervals were calculated. We found minor changes with age, no differences between right and left side, significant sex differences, and significant changes with increasing gait speed. The reference data are considered valid in an indoor laboratory situation. If gait analysis is used for evaluation of disabled people, a comparison must be made with data from healthy people. This study provides such normative data for joint angle parameters.

Three-dimensional computer model of the human buttocks, in vivo

Abstract: In an effort to reduce the incidence of decubitus ulcers among wheelchair users, current work in cushion design concentrates on minimizing the pressure at the buttock-cushion interface. Finite element analysis can show the stress levels throughout the soft tissue between the cushion and the ischial tuberosity and give designers a better indication of the effects of a particular cushion. Finite element models were generated of the tissues around the ischial tuberosities of male and female subjects. Linear three-dimensional models were generated using a 386 computer and solved with infinitesimal deflection theory. The resulting minimal principal stresses were 17 kPa and 15 kPa at the buttock-cushion interface for seated male and female subjects, respectively. Computational results were verified experimentally with magnetic resonance imaging and interface pressure measurements.

The Southampton hand : an intelligent myoelectric prosthesis

Abstract: The form of the control and structure of the mechanism of an artificial hand are important factors which tend to dictate the prosthesis' level of use. Conventional prostheses are simple devices with limited functional range and a control format that requires high levels of user concentration for successful operation. The Southampton Adaptive Manipulation Scheme (SAMS) is a hierarchical control format that allows a larger number of independent motions to be controlled while requiring a smaller degree of user input. The SAMS control has been applied to different hand mechanisms, both custom-made and modified commercial systems. Their application with users shows them to have a performance on a par with, or superior to, other conventional devices. The form of prosthesis control is reviewed and the development of, and clinical experiments with, the Southampton Hand are outlined.

Continuous regional analgesia by intraneural block: effect on postoperative opioid requirements and phantom limb pain following amputation.

Abstract: The objective of this study was to assess the effectiveness of a previously described technique of regional analgesia (continuous infusion of local anesthetic through a catheter placed at the time of amputation within the exposed sciatic or posterior tibial nerve) on relieving the postoperative pain in a heterogeneous group of patients who underwent lower extremity amputations. A second objective was to determine the effect of such treatment on the incidence and characteristics of phantom limb pain 6 months or more after surgery in the same patients. The study design was retrospective, unblinded, controlled (postoperative pain), and unblinded questionnaire and interview (phantom pain) were utilized. Subjects were inpatients at Harborview Medical Center, University of Washington, Seattle, WA. Nineteen bupivacaine-treated and 40 nonbupivacaine-treated patients who underwent lower extremity amputation subsequent to trauma, infection, long-standing injury (poor or no function), congenital deformity, or burns were evaluated in the postoperative pain management assessment. Nine treated and 12 untreated patients were interviewed in the phantom pain assessment. Bupivacaine 0.5% 2-6 ml/h was infused through a polyamide 20-gauge catheter inserted into the sciatic or posterior tibial nerve sheath under direct vision at the time of surgery. All patients, treated and control, received opioid analgesics systemically during the 72-hour period of study. The postoperative opioid analgesic requirement of treated patients was compared with that of control patients who received opioid analgesics alone. A questionnaire was administered to assess presence, severity, and character of phantom pain.(ABSTRACT TRUNCATED AT 250 WORDS)

Tibial bone density loss in spinal cord injured patients: effects of FES exercise.

Abstract: A group of 37 spinal cord injured (SCI) patients underwent bone density measurements at the distal and proximal end of the tibia by a special computed tomography scanner, the OsteoQuant. Fifteen of these patients had follow-up measurements while enrolled in a lower-limb exercise training program with functional electrical stimulation (FES). The pre-exercise measurements revealed a strong correlation (0.88 < or = r < or = 0.90) of trabecular, subcortical, and cortical bone density between the distal and proximal ends of the tibia. The expected bone density loss during the first two years post injury (as calculated from the regression lines of bone density vs. time post injury) amounted to 51.5% for trabecular, 44.2% for subcortical, and 32.7% for cortical bone. No major bone density loss was calculated after 7 years post injury. Analysis of the bone density data during the FES exercise program revealed various degrees of loss. However, the rate of bone loss for this FES exercise group was less than expected from the regression lines. The reduction of bone loss was between 0.2 and 3.3% per year, and was significant (p < 0.05) for all bone parameters at the distal end and for trabecular bone density at the proximal end of the tibia. These bone density measurements revealed a potentially positive effect of FES exercise intervention for the rehabilitation of SCI patients.

Pressure redistribution by molded inserts in diabetic footwear: a pilot study.

Abstract: A small-scale trial is described to demonstrate and evaluate the redistribution of plantar pressure resulting from the use of custom-molded inserts in the orthopedic shoes of diabetic patients at risk of plantar ulceration. A pressure-measuring insole based on force-sensitive resistor technology enabled the load distribution to be compared using molded inserts and flat inserts fitted into the same shoes. An analysis of the 12 peaks of pressure that could be identified under a discrete metatarsal head of six subjects in the trial showed that the pressure was significantly reduced with the use of molded inserts (flat inserts: 305 +/- 79 kPa; molded inserts: 216 +/- 70 kPa; n = 6 p < 0.005). Technical limitations of the equipment and the difficult choice of match of flat insert to molded for comparison suggest that further studies are required for a definitive result.

Biomechanical assessment of below-knee residual limb tissue.

Abstract: In vivo indentation properties of the residual limb tissues of a group of senior subjects with below-knee (BK) amputation were measured and compared with those of nondisabled young adults. It was found that differences attributable to site variations, states of muscular activity, and the differences between the nondisabled young group and the group consisting of the seniors with amputation were all noted to be highly significant statistically. However, paired comparison between the residual limb and the sound contralateral limb of the senior group showed no significant difference. Residual limb properties measured right before the first prosthetic measurements and fittings and those measured at the first outpatient follow-up were found to be slightly different.

Anaerobic power output and propulsion technique in spinal cord injured subjects during wheelchair ergometry

Abstract: In order to investigate the influence of the level of the spinal cord injury (SCI) on anaerobic or short-term power production and propulsion technique, 23 male SCI subjects performed a 30-second sprint test on a stationary wheelchair ergometer. Kinematic parameters were studied both inter- and intra-individually. Subjects with a cervical lesion showed a lower mean power output (21.5 Watt, one-sided) than the other subjects; whereas, no differences were found between subjects with a thoracic or lumbar injury (46.9, 63.7, and 49.1 Watt, one-sided). Unexpectedly, no differences were found for the effectiveness of the force applied on the rim between subjects with a cervical injury and the other subjects. It is suggested that the high hand rim velocity reached by subjects with a lower injury cause coordination problems. Reduced arm functionality of subjects with a cervical lesion appeared to cause a higher inward directed force. Arm functionality and rim velocity may have a compensating effect with respect to the effectiveness of force. The kinematics of subjects with a cervical lesion differed strongly from subjects with a lower lesion. Propulsion technique appeared to be intra-individually consistent, which is reflected in the consistency of the force curves, the power output curves, and the movement patterns. Large inter-individual differences in propulsion technique were found. It is concluded that the large diversity in capacity of the SCI population should be taken into account with respect to guidelines and requirements for the environmental space of the SCI population.

Who is at risk of limb loss and what to do about it

Abstract: Lower limb amputations were performed on over 105,000 individuals in United States short-stay hospitals between 1989 and 1992. Additional amputations were performed in VA, military, Indian Health, and charitable orthopaedic hospitals. Half of all lower extremity amputations occurred in individuals with diabetes. When the causal chain leading to diabetic amputations was examined in 80 consecutive patients at the VA Medical Center, Seattle, WA, 23 unique pathways were identified. Multiple pathway components were identified for 96% of patients, while in 4% a single ischemic pathway was sufficient in itself to require amputation. The majority of the scenarios leading to amputation began when patients with absent peripheral sensation sustained a pivotal event that initiated the causal chain to amputation. In nearly half the patients, this event was foot-wear-related. The pivotal event was followed by ulceration and faulty wound healing in 73% of patients. Each year thousands of individuals with diabetes undergo amputation in VA facilities, resulting in substantial cost to the Department of Veterans Affairs and to themselves. If the VA is to address the prevention or delay of limb loss, the causal pathway information indicates that attention to the footwear of diabetic patients is necessary.

Assessment of skin blood content and oxygenation in spinal cord injured subjects during reactive hyperemia

Abstract: This study was undertaken to determine whether the reactive hyperemia response following ischemia in spinal cord injured (SCI) individuals is different from that which occurs in able-bodied (AB) individuals. The reactive hyperemia response was produced by applying a pressure of 150 mmHg for 300 s, 600 s, and 900 s to the skin over the greater trochanter in 10 SCI and 10 AB subjects using a computer-controlled pneumatic indentation system. The changes in blood content and oxygenation in the superficial vessels of the skin, associated with indentation, were monitored using reflectance spectrophotometry. A brief pressure of 80 mmHg, to simulate finger pressing (blanching), was applied to the same site to detect changes in reflow behavior during the hyperemic period. The results indicate that the reactive hyperemia response in SCI group was not substantially different from AB group although the reflow rate after load release was slower in the SCI group compared with the AB group.

Toward classification of dysphagic patients using biomechanical measurements.

Abstract: Identification of a patient at risk of aspiration is a major problem in the rehabilitation of the dysphagic patient. The present methods of diagnosis are based on clinical evaluation or videofluorography or fiberoptic endoscopic examination of swallowing (FEES). Recently, we developed biomechanical techniques for noninvasive quantitative assessment of the dysphagic patient. The purpose of the present investigation was to assess the clinical validity of the technique. In a double-blind study, both biomechanical test results and videofluorography (including bedside evaluation) results were used to independently classify the patients into four categories of risk for aspiration. Of the 36 patients studied, there was complete agreement between the biomechanical and clinical classifications in 21 patients. In 11 patients, the biomechanical technique overestimated the risk by one category, and underestimated the risk by one category in four patients. The biomechanical technique presents a useful tool for continued patient assessment; however, further studies are needed.

Automatic speech recognition to aid the hearing impaired: prospects for the automatic generation of cued speech

Abstract: Although great strides have been made in the development of automatic speech recognition (ASR) systems, the communication performance achievable with the output of current real-time speech recognition systems would be extremely poor relative to normal speech reception. An alternate application of ASR technology to aid the hearing impaired would derive cues from the acoustical speech signal that could be used to supplement speechreading. We report a study of highly trained receivers of Manual Cued Speech that indicates that nearly perfect reception of everyday connected speech materials can be achieved at near normal speaking rates. To understand the accuracy that might be achieved with automatically generated cues, we measured how well trained spectrogram readers and an automatic speech recognizer could assign cues for various cue systems. We then applied a recently developed model of audiovisual integration to these recognizer measurements and data on human recognition of consonant and vowel segments via speechreading to evaluate the benefit to speechreading provided by such cues. Our analysis suggests that with cues derived from current recognizers, consonant and vowel segments can be received with accuracies in excess of 80%. This level of performance is roughly equivalent to the segment reception accuracy required to account for observed levels of Manual Cued Speech reception. Current recognizers provide maximal benefit by generating only a relatively small number (three to five) of cue groups, and may not provide substantially greater aid to speechreading than simpler aids that do not incorporate discrete phonetic recognition. To provide guidance for the development of improved automatic cueing systems, we describe techniques for determining optimum cue groups for a given recognizer and speechreader, and estimate the cueing performance that might be achieved if the performance of current recognizers were improved.

Modelling the propulsion characteristics of a standard wheelchair.

Abstract: Recent wheelchair modelling work has focused on the efficiency of the human-racing wheelchair interaction. This paper builds on this work, investigating the development of a model appropriate for those using standard wheelchairs. A wheelchair racing model was initially used as the starting point for the generation of a number of model variations. Force predictions from these variations were compared to load cell data taken from an instrumented wheelchair during propulsion. Additional models where then developed, based on the characteristics of the models that performed best, and used to predict the forces in a second group of subjects. The analysis procedure was originally based on the calculation of a model index as a mathematical estimation of the theoretical closeness each model prediction had with the observed force. Visual comparisons of the force versus time were then incorporated into the procedure for evaluating the physical appearances of the profiles. The combination of the statistical and visual analysis led to selection of the final models for estimating the starting, constant, and stopping phases of wheelchair propulsion. The resulting models provide insight into the effects of a variety of factors on efficiency during propulsion in a standard chair.

Cardiorespiratory status and movement capabilities in adults with limb amputation.

Abstract: Two hundred and thirty subjects with various levels of upper and lower limb amputation were examined with regard to cardiac and respiratory functions. The subjects were examined at rest and in balanced wheelchair ergometer testing. Noncontinuous step-by-step increased loading was performed. The data given are for age-group 20-40 who sustained traumatic amputation and suffered no prior respiratory or circulatory disease. Subjects after above-knee (AK), bilateral AK or AK plus below-knee amputation) showed a loss of the reaction of an adequate systolic output rise in wheelchair ergometer testing. In the adults with amputation, the increase of minute stroke volume occurred solely at the expense of heart rate. The contractile capacity of myocardium was decreased. Cardiac indicator value in subjects with AK or bilateral AK amputation in sub-maximal exercises training appeared to be lower than in the control group. A reduced work capacity takes place in subjects after body mass loss. The maximal oxygen intake in subjects with bilateral lower limb amputation was less than in the control group. The breaking of correlation interrelationships between working capacity indicators was revealed in the subjects with bilateral lower limb amputation. The adults with upper limb amputation showed a reduction in pulmonary ventilation. During exercise training, the capacity for adequate pulmonary ventilation was lost in the above-mentioned subjects. This research demonstrates that movement capabilities in adults with amputation depend not on the level of amputation and residual limb condition, but to a great extent upon the dynamic capabilities of the cardiac and respiratory muscular systems' ability to adjust to the limb loss.

Evolution of mechanical fingerspelling hands for people who are deaf-blind.

Abstract: People who are both deaf and blind can experience extreme social and informational isolation due to their inability to converse easily with others. To communicate, many of these individuals employ a tactile version of fingerspelling and/or sign language, gesture systems representing letters or words, respectively. These methods are far from ideal, however, as they permit interaction only with others who are in physical proximity, knowledgeable in sign language or fingerspelling, and willing to engage in one of these "hands-on-hands" communication techniques. The problem is further exacerbated by the fatigue of the fingers, hands, and arms during prolonged conversations. Mechanical hands that fingerspell may offer a solution to this communication situation. These devices can translate messages typed at a keyboard in person-to-person communication, receive TDD (Telecommunication Devices for the Deaf) telephone calls, and gain access to local and remote computers and the information they contain.

Drag and sprint performance of wheelchair basketball players.

Abstract: The purpose of this study was to measure the wheelchair drag and maximal sprint performance abilities of wheelchair basketball players and to make comparisons between male and female players. A group of nine male and eight female wheelchair basketball players attending a national training camp consented to serve as subjects. Each subject completed six coast-down trials at speeds from a walking pace (1 to 1.5 m/s) to maximal for determining wheelchair drag and then performed four maximal sprint trials from a stationary start over the length (35 m) of the gymnasium floor. A portable computer that recorded the time to the nearest 0.001 second of each half revolution of a rear wheel was attached to the wheelchair of each subject. The drag force during the coast-down trials and the power output during the sprint trials were determined from the recorded data. Differences between the genders in a number of subject and trial variables were evaluated by t-tests using the 0.05 level of significance. There were no significant differences between the means of the male and female groups in age (27 vs. 28 yrs), wheelchair mass (12.0 vs. 11.61 kg), or regression predicted drag forces at speeds of 2 m/s (5.3 vs. 5.5 N) and 5 m/s (16.7 vs. 13.5 N). The male subjects were significantly heavier (78.3 vs. 59.1 kg) and had a higher tire pressure (123 vs. 94 psi). In the sprint trial results, the males exhibited a significantly higher maximal speed (4.75 vs. 4.08 m/s), higher peak acceleration (1.32 vs. 1.03 m/s/s), and a higher peak power output (530 vs. 264 w).

Automated fabrication of mobility aids: review of the AFMA process and VA/Seattle ShapeMaker software design

Abstract: Computer-aided design and manufacture of prosthetic and orthotic devices has recently moved out of the laboratory into clinical use. The Department of Veterans Affairs Rehabilitation Research and Development Service has directed coordinated evaluation and development projects of this emerging technology under the name: Automated Fabrication of Mobility Aids or AFMA. One of the major results of the effort was the creation of mobility aid design software (ShapeMaker) concurrent with AFMA clinical testing of preexisting systems and development efforts. In order to provide a foundation for future discussions regarding AFMA, this paper provides a descriptive review of the AFMA processes and a review of the conceptual basis for the ShapeMaker AFMA software development.

A survey of marginal wheelchair users.

Abstract: Significant numbers of wheelchair users experience difficulties with propulsion due to impaired upper limb function (termed marginal users for this study) A survey of wheelchair users in Tayside, Scotland, was carried out to identify and describe the marginal user population and their propulsion difficulties Subjects for the survey were identified from the records of National Health Service wheelchair users at Dundee Limb Fitting Centre Subjects were interviewed at home about their wheelchair-propelling experiences Survey results indicated that marginal users represent approximately 15% of the occupant-propelled wheelchair population The average age of the marginal users surveyed was 48 years and the modal diagnosis was multiple sclerosis Fifty-nine percent of the marginal users questioned felt that their wheelchairs were not adequate for their requirements

Balance and stabilization capability of paraplegic wheelchair athletes.

Abstract: The orientation of paraplegic athletes toward adapted sport activities required good knowledge of their functional characteristics. Wheelchair locomotion, especially for highly dynamic situations, poses the problem of trunk equilibrium management and head stabilization. The study aimed at designing a quantitative method to assess the ability of paraplegics to obtain trunk balance under dynamic stresses, and to analyze the various balance strategies, according to the spinal lesion level of the subjects. High (HPA) and low (LPA) paraplegic athletes were subjected to four series of antero-posterior stresses of increasing intensity, generated by an oscillating platform. By means of a computerized video-based movement analyzer, acceleration in the saggittal plane was measured at four different spinal level and, for each one, a damping factor was determined. This factor, computed at the head level, appeared to be representative of the subjects' ability to maintain balance. We attempted to differentiate balance strategies in the LPA and HPA groups through analysis of the relative contributions to damping of the thoracic and cervical spinal segments. The first results show an increasing tendency of neck reflex stiffening according to the neurological level.

Evaluation of methods for determining rearward static stability of manual wheelchairs

Abstract: Wheelchair standards have been under development for several years. A set of tests has been approved by the American National Standards Institute (ANSI) and by the International Standards Organization (ISO) but continue to be refined. Static stability is one of the indicators used to evaluate manual wheelchairs and is measured by placing a loaded wheelchair on a platform that is tilted until the wheelchair's front wheels lift off of the platform. Currently, if the wheelchair parking brakes slip, a block is placed behind the rear wheels and the tip angle is measured. The results for eight different wheelchairs with three load cases showed that the rearward tip angle for the block is significantly different (p < 0.05) from that with the brakes alone.

A skin indentation system using a pneumatic bellows.

Abstract: A pneumatic indentation system using a copper bellows has been developed for physiological studies where a controlled uniaxial compressive force is required to be applied to the surface of the skin. Such a system is useful for studies where the physiological response of the tissues is to be monitored following a known loading history. The indentation system is driven by a vacuum/compression pneumatic pump through solenoid valves under closed-loop computer control. A load cell placed between the indentor and bellows monitors the applied force providing a feedback signal to the computer. The signal from the computer activates the valves supplying air pressure to the bellows, and the applied force is controlled using a digital closed-loop protocol. This system can be used to provide a controlled loading sequence to the skin without utilizing gravitational forces, which allows the subject to keep a more natural position during the experiment.

Initial clinical evaluation of a wheelchair ergometer for diagnostic exercise testing: a technical note.

Abstract: The purpose of this initial study was to evaluate a new wheelchair ergometer (WCE) and exercise test protocol for the detection of coronary artery disease in men with lower limb disabilities. Forty-nine patients (63 +/- 9 yr) completed WCE tests without complications. Peak heart rate was 84 +/- 15% (mean +/- SD) of age-predicted maximum and peak double product was 223 +/- 62 x 10(2). The specified target heart rate (> or = 80% age-predicted maximal) or a positive result was achieved in 76% of tests. Fourteen tests were rated positive, 21 as negative and 14 as nondiagnostic for exercise-induced ischemia. In 18 patients who underwent coronary angiography, the predictive value was 100% (10/10) for a positive, and 50% (2/4) for a negative WCE test result. These results suggest that WCE is a viable initial diagnostic option for some persons who cannot adequately perform treadmill or cycle ergometry exercise.

Distributed random electrical neuromuscular stimulation: effects of the inter-stimulus interval statistics on the EMG spectrum and frequency parameters.

Abstract: An electrophysiological approach was used to study a distributed random electrical neuromuscular stimulation (ENMS) scheme in which a probability density is assigned to the inter-stimulus intervals (ISI) of the stimuli. One of the objectives of using ENMS techniques in the study of skeletal muscles is to obtain information about the electrical, physiological, and mechanical properties of muscles in a near-physiological situation under a well-controlled experimental design in which problems related to the uncertainty of firing patterns of the central nervous system and physiological interference are avoided. In particular, ISI with a Gaussian density were varied in mean rate, standard deviation (SD), and coefficient of variation. The influence of varying ISI, and the interaction of the ISI statistics with compound motor unit action potentials (CMUAP) on EMG power spectra and their frequency parameters, was assessed theoretically using a mathematical model which is similar to that of EMG signal generation in the electrophysiological case. In order to quantify the effects of ISI statistics on the EMG spectrum, the median frequency was calculated as a function of stimulation rate using analytical expressions for various values of the coefficients of a Gaussian ISI variation. The results obtained suggest that 1) the interaction between ISI statistics and the shape of the CMUAP plays a major role in determining the EMG spectrum; 2) the median frequencies (MF) determined from EMG spectra tend to increase with increasing mean rates of stimulation for a given CMUAP. The rate of increase of the MF depends on the coefficient of the ISI variation; 3) the EMG spectra of random electrically stimulated muscle show peaks at the mean rate of stimulation, and multiples of it, when the coefficient of variation of ISI is small. These peaks decrease in magnitude with increasing coefficients of variation of ISI; and, 4) a variation in the ISI should be introduced in the ENMS, when a reproduction of 'normal' EMG spectra is needed. These results are consistent with those reported for voluntary contraction of skeletal muscles.

Gait analysis: technology and the clinician.

Abstract: Patients' walking disabilities were first diagnosed with the trained eye of an informed examiner. Motion deviations were observed and the cause extrapolated from a knowledge of normal muscle function. This approach still meets the needs of some disabilities, but is inadequate for many others. Today, technical advances allow the quantification of motion analysis to three-dimensional accuracy and have expanded the dimensions of ground reactions forces to power calculations. Dynamic EMG similarly delineates the timing and intensity of the muscles to define abnormalities in control. Most recently, advanced mechanics and computer graphics have provided a means of qualifying and displaying the muscle forces involved in gait. Model design, however, begins with the analysis of normal function. Can these models be transferred directly to the disabled? The designers must accept the challenge to confirm that the differences attributed to pathology accurately reflect the patient's mixture of reduced passive joint mobility, weakness and/or spasticity. The practice of considering the joints individually must be extended to include the reactions within the whole limb. Communication is critical. As engineering sophistication in gait analysis progresses, there must be a concerted effort to present the developments in terms that the practicing clinicians will understand. The engineer's language is numbers, signs, and formulae. Clinicians analyze their patients and plan their treatment according to specific motions and muscles. For optimum transfer of the engineering accomplishments to patient care, the language of the clinician must be the communication path. Amidst the technical accomplishments is the need to preserve the quality of observational gait analysis. This technique remains the first step in the treatment of patients' gait abnormalities. If the physician fails to identify a problem, the therapeutic need will be missed. Physical therapists use their observational skills for treatment planning and evaluation. Orthotists and prosthetists depend on observation to evaluate the functional success of their devices. The concluding principle is that the purpose of gait analysis is to improve the patient's ability to walk. The analytical technique selected should be in balance with the level of need and objectivity.

Report on the evaluation of the DAV/Seattle Knee.

Abstract: The Department of Veterans Affairs (VA) Rehabilitation Research and Development Service, Technology Transfer Section (TTS) managed a clinical evaluation of the DAV/Seattle Knee with collaboration from the Prosthetic and Sensory Aids Service (PSAS), VA Central Office (VACO) at 16 VA Medical Facilities, recruiting 46 subjects. The DAV/Seattle Knee was designed to provide a functional, lightweight artificial knee that would give veterans, with above-knee amputations, greater mobility than they experienced with other comparative man-made knees. This national evaluation was conducted to determine the acceptance of the DAV/Seattle Knee by veterans prescriptive criteria and to determine what modifications, if any, were needed to improve the product for optimal use by the targeted population and to enhance its marketability. TTS, with collaboration from PSAS/VACO, managed a clinical evaluation on 28 units with fluid swing control. The evaluation trials were conducted between May 1992 and May 1993. During the initial phase of the clinical trials, a common problem of the piston shaft end breaking was identified. This was a fail-safe situation; the knee support structure maintained its integrity and did not cause the subject to fall. All units were immediately returned to the manufacturer for installation of new damper mounts. Forty-six subjects were accepted; 28 fitted; 23 completed evaluation for 30 days, 8 subjects are currently wearing the DAV/Seattle Knee. The subjects' responses from the clinical trials successfully demonstrated that the DAV/Seattle Knee is safe and reliable when properly matched to the user's weight, stump length, and activity requirements.

Clinical evaluation of the modular electromechanical lock actuator for above-elbow prostheses: a preliminary report.

Abstract: The Modular Electromechanical Lock Actuator (MELA) is the result of research and development (R&D) conducted under the direction of Dudley S Childress, PhD, at the Northwestern University Prosthetics Research Laboratory (NUPRL), Chicago, Illinois NUPRL, based upon their experience with prostheses for persons with high-level, upper-limb amputations, developed MELA to provide users with more efficient, versatile control and operation of their existing, cable-operated, positive-locking elbow and wrist components The design of MELA has advanced to the point where it has the potential to improve the functionality and effectiveness of existing, body-powered or manually positioned above-elbow prostheses This R&D effort has resulted in a pre-market model that is now ready for the national field evaluation part of the technology transfer process coordinated through the VA Rehabilitation Research and Development Service, Technology Transfer Section

Voice output reader for displays on video cassette recorders and other domestic products

Abstract: The increasing use of electronic displays in domestic products can pose great problems for blind people wishing to use microwave ovens, video cassette recorders, hi-fi systems, etc. One method of trying to solve these problems is to provide a handheld "display reader" that can translate the alphanumeric and symbolic information presented on the display into speech. A prototype system has been developed and evaluated. User requirements for this device and the problems of the image sensor, the image processing method, and the user interaction with the system are also discussed.