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Technology and Disability communicates knowledge about the field of assistive technology devices and services, within the context of the lives of end users - persons with disabilities and their family members. While the topics are technical in nature, the articles are written for broad comprehension despite the reader's education or training.
Technology and Disability's contents cover research and development efforts, education and training programs, service and policy activities and consumer experiences.
The term Technology refers to assistive devices and services.
- The term Disability refers to both permanent and temporary functional limitations experienced by people of any age within any circumstance.
- The term and underscores the editorial commitment to seek for articles which see technology linked to disability as a means to support or compensate the person in daily functioning.
The Editor also attempts to link the themes of technology and disability through the selection of appropriate basic and applied research papers, review articles, case studies, programme descriptions, letters to the Editor and commentaries. Suggestions for thematic issues and proposed manuscripts are welcomed.
Abstract: In the aim of investigating the influence of various mechanical parameters on wheelchair propulsion efficiency during real life displacements, either outside or inside the laboratory, a wireless wheelchair ergometer (WWE) has been designed, which is able to measure the six components (F_x, F_y, F_z, M_x, M_y, M_z ) of the efforts applied by the subject on right and left handrims and on the seat. Wheelchair's kinematics is measured by two angular potentiometers fixed on rear…wheels' axles, a 3-D accelerometer and a Y-axis gyroscope fixed on wheelchair's frame. The 24 signals produced by these sensors are sampled at 500 Hz by a 16-bit A/D conversion card slotted into a mini PC fixed under the seat, and data are then sent to a remote computer using the IEEE 802.11b and TCP/IP wireless protocols. A preliminary study with one able-bodied subject who performed a straightforward 60-m's run on the track of an indoor stadium demonstrated that the WWE allows exploring some unknown aspects of wheelchair locomotion directly on the field. The future results obtained with this original research instrument should provide some answers to the numerous questions encountered by clinicians in their practise, and help wheelchair manufacturers to improve their products.
Keywords: human locomotion, wheelchair ergometer, real life measurements, wireless protocol, biomechanics
Abstract: The Compumedics "Siesta" datalogger was used to set up and trial the potential and initial applications of a remote datalogger to study a range of physiological and other changes in spinal cord injured (SCI) patients undergoing rehabilitation following traumatic injury. The group of 6 patients (weeks 3 to 34 post injury) was selected due to changes expected with neurological and functional recovery. The 32 channel datalogger was used to record signals of ECG, Thoracic and Abdominal…respiration, Pulse Oximetry, piezoelectric accelerometers and thermistors. Five (5) tests were completed for each subject over a period of three (3) months. This study extended on work in sleep lab testing in normals and SCI at Austin RMC. Data analysis involved pattern recognition, simple analysis of heart rate signal, and more complex focused signal analysis. Datalogger measurements have revealed some changes in physiology including ``autonomic failure'' unique to SCI patients during normal activity. Further research is required to consolidate results through a larger study group.
Abstract: Seven paraplegic Functional Electrical Stimulation (FES) experienced users volunteered to test a newly developed eight channel stimulation system. The goal was to discover the influence of various stimulation parameters on the gait quality. As additional task the usability should be improved and simplified as much as possible. Commercially available hydrogel electrodes were attached to quadriceps and gluteus muscles to achieve hip and knee extension, to peroneal nerve to elicit flexion reflex and later also to…adductor muscles. All patients were positive about the handling of the stimulation system. Especially the wireless remote control was highly approved. First results demonstrate the importance of an amplitude ramp during stimulation onset (0.1–0.4 s) resulting in a smooth and more "natural" movement. For an adequate step length and walking speed the timing of quadriceps and peroneal nerve stimulation at the end of the swing phase are crucial. Experienced patients with a higher walking speed require a short swing phase and an overlap of quadriceps decay and peronaeus onset (0–0.2 s). Activation of the adductor muscles reduces knee abduction and lead to a better knee trajectory during standing up and better leg movement during the swing phase. Patients can perform 15–25 steps per minute with a step length of 20–30 cm. The walking distance until exhaustion or muscle fatigue occurs is 4–60 m. The analysis of the used stimulation sequences brought up guidelines for a fast and effective parameter optimization procedure.
Abstract: This paper describes an instrumented test and training tricycle that was designed for persons with complete or incomplete paraplegia. The tricycle can be used as a stationary device for training and adjustment of stimulation parameters or as a mobile cycle. It is driven either by the remaining muscular activity of a person with incomplete paraplegic and/or by Functional Electrical Stimulation (FES) of paralysed leg muscles. Paralysed muscles are stimulated in dependence of the actual crank angle…by a 10-channel current controlled stimulator. The geometry of the cycle is easily adjustable to individual demands. The tricycle is instrumented with an auxiliary motor, force measuring cranks, and devices for measurement of knee and ankle angles. The control is based on a laptop computer. Predefined measurement modes are available for isometric and isokinetic measurements in order to determine the optimal stimulation regimes and geometrical settings for an individual subject with paraplegia.
Abstract: The purpose of the present study was to determine the effect of a 4-week training program on a newly developed hybrid functional electrical stimulation (FES)-cycle on physical fitness in spinal cord-injured (SCI) individuals. Ten SCI individuals (age 23–53 years, lesion level range T3–T11) participated and trained 8–12 times in 4 weeks on the hybrid FES-cycle (voluntary arm-contractions and stimulation of leg muscles). Leg volume was measured. During a graded hybrid exercise test, peak oxygen…consumption (VO2peak), peak power output (POpeak) and power of the legs (dP) wer measured pre and post training. Upper leg volume increased significantly (8.5% (p = 0.047) and 8.3% (p = 0.018) for the right and left leg, respectively). POpeak and VO2peak increased 11.7% (p = 0.012) and 9.3% (p = 0.015), respectively. There was no significant difference in dP between pre and post training. After only 4 weeks of training, considerable training effects were observed, which are comparable to longer training studies in literature. The results of this study indicate that hybrid training on the new hybrid FES-cycle is an appropriate training method for individuals with a spinal cord injury to increase physical fitness.
Abstract: The rehabilitation robotic systems FRIEND-I/-II belong to the category 'intelligent' wheelchair mounted manipulators. The systems are being developed at the Institute of Automation (IAT), University of Bremen, since 1997. They are used as a personal assistant to support disabled persons with upper-limb impairments in daily life situations as well as in the working environment. This paper gives an user oriented overview of the facilities of the FRIEND-I system as well as a description of the innovations…of the currently developed FRIEND-II system. It will be shown that the concept of semi-autonomy enables the development of rehabilitation robotic systems that process tasks robustly on a relatively high level of abstraction. Additionally, the paper underlines the necessity to improve the manipulative flexibility of rehabilitation robots and describes the new control concept – Kinematic Configuration Control – of FRIEND-II's dexterous robot arm having fluidic 5-finger hand and humanlike 7-joints kinematics.