Technology and Health Care - Volume 7, issue 6

Authors: de Vries, Theo J.A. | Veltink, Peter H. | Koopman, Bart F.J.M. | Hermens, Hermie J.

Article Type: Editorial

DOI: 10.3233/THC-1999-7601

Citation: Technology and Health Care, vol. 7, no. 6, pp. 381-381, 1999

Authors: Veltink, Peter H.

Article Type: Research Article

Abstract: Artificial motor control systems may reduce the handicap of motor impaired individuals. Sensors are essential components in feedback control of these systems and in the information exchange with the user. The objective of this paper is to give an overview of the applications of sensors in the artificial control of human mobility. These applications may either require an accurate estimate of the measured physical quantities or can be based on learning the relation between sensory information and control actions by example. Actual use of sensors in artificial motor control systems requires that the user experienced complexity of the system is …not increased, while improving the repeatable and flexible functioning of the system. Therefore, the sensors need to be integrated with the mechanical part of the artificial support system or implanted, the information exchange between sensor and controller should be wireless and automatic in-use calibration is a desired feature. Show more

DOI: 10.3233/THC-1999-7602

Citation: Technology and Health Care, vol. 7, no. 6, pp. 383-391, 1999

Authors: Haugland, Morten | Sinkjær, Thomas

Article Type: Research Article

Abstract: Functional Electric Stimulation (FES) is today available as a tool in muscle activation used in picking up objects, in standing and walking, in controlling bladder emptying, and for breathing. Despite substantial progress over nearly three decades of development, many challenges remain to provide a more efficient functionality of FES systems. The most important of these is an improved control of the activated muscles. Instead of artificial sensors for feedback, new developments in electrodes to do long-term and reliable recordings from peripheral nerves emphasize the use of the body’s own sensors. These are already installed and optimised through millions of years …of natural evolution. This paper presents recent results on a system using electrical stimulation of motor nerves to produce movement and using the natural sensors as feedback signals to control the stimulation that can replicate some of the functions of the spinal cord and its communication with the brain. We have used the nerve signal recorded from cutaneous nerves in two different human applications: (1) to replace the external heel switch of a system for correction of spastic drop foot by peroneal stimulation, and (2) to provide an FES system for restoration of hand grasp with sensory feedback from the fingertip. For the bladder function, the sacral root stimulator is a useful control tool in emptying the bladder. To decide when to stimulate, we are at present carrying out experiments on pigs and cats using cuff electrodes on the pelvic nerve and sacral roots to record the neural information from bladder afferents. This information can potentially be used to inhibit unwanted bladder contractions and to trigger the FES system and thereby bladder emptying. Future research will show whether cuffs and other types of electrodes can be used to reliably extract signals from the large number of other receptors in the body to improve and expand on the use of natural sensors in clinical FES systems. Show more

Keywords: FES, natural sensors, nerve cuff electrode, drop-foot, hand grasp, bladder

DOI: 10.3233/THC-1999-7603

Citation: Technology and Health Care, vol. 7, no. 6, pp. 393-399, 1999

Authors: Riso, R.R.

Article Type: Research Article

Abstract: A continuing challenge for prostheses developers is to replace the sensory function of the hand. This includes tactile sensitivity such as finger contact, grip force, object slippage, surface texture and temperature, as well as proprioceptive sense. One approach is sensory substitution whereby an intact sensory system such as vision, hearing or cutaneous sensation elsewhere on the body is used as an input channel for information related to the prosthesis. A second technique involves using electrical stimulation to deliver sensor derived information directly to the peripheral afferent nerves within the residual limb. Stimulation of the relevant afferent nerves can ultimately come …closest to restoring the original sensory perceptions of the hand, and to this end, researchers have already demonstrated some degree of functionality of the transected sensory nerves in studies with amputee subjects. This paper provides an overview of different types of nerve interface components and the advantages and disadvantages of employing each of them in sensory feedback systems. Issues of sensory perception, neurophysiology and anatomy relevant to hand sensation and function are discussed with respect to the selection of the different types of nerve interfaces. The goal of this paper is to outline what can be accomplished for implementing sensation into artificial arms in the near term by applying what is present or presently attainable technology. Show more

DOI: 10.3233/THC-1999-7604

Citation: Technology and Health Care, vol. 7, no. 6, pp. 401-409, 1999

Authors: Harwin, W.S.

Article Type: Research Article

Abstract: As healthcare costs rise and an aging population makes an increased demand on services, so new techniques must be introduced to promote an individuals independence and provide these services. Robots can now be designed so they can alter their dynamic properties changing from stiff to flaccid, or from giving no resistance to movement, to damping any large and sudden movements. This has some strong implications in health care in particular for rehabilitation where a robot must work in conjunction with an individual, and might guiding or assist a persons arm movements, or might be commanded to perform some set of …autonomous actions. This paper presents the state-of-the-art of rehabilitation robots with examples from prosthetics, aids for daily living and physiotherapy. In all these situations there is the potential for the interaction to be non-passive with a resulting potential for the human/machine/environment combination to become unstable. To understand this instability we must develop better models of the human motor system and fit these models with realistic parameters. This paper concludes with a discussion of this problem and overviews some human models that can be used to facilitate the design of the human/machine interfaces. Show more

DOI: 10.3233/THC-1999-7605

Citation: Technology and Health Care, vol. 7, no. 6, pp. 411-417, 1999

Authors: Krebs, H.I. | Hogan, N. | Volpe, B.T. | Aisen, M.L. | Edelstein, L. | Diels, C.

Article Type: Research Article

Abstract: We are applying robotics and information technology to assist, enhance, and quantify neuro-rehabilitation. Our goal is a new class of interactive, user-affectionate clinical devices designed not only for evaluating patients, but also for delivering meaningful therapy via engaging “video games”. Notably, the novel robot MIT-MANUS has been designed and programmed for clinical neurological applications, and has undergone extensive clinical trials for more than four years at Burke Rehabilitation Hospital – White Plains, NY. This paper will review results of the first clinical trial of 20 patients, which showed that: Stroke patients treated daily with additional robot-aided therapy during …acute rehabilitation had improved outcome in motor activity at hospital discharge, when compared to a control group that received only standard acute rehabilitation treatment. This improved outcome was sustained after three years. The neuro-recovery process continued far beyond the commonly accepted 3 months post-stroke interval. Show more

DOI: 10.3233/THC-1999-7606

Citation: Technology and Health Care, vol. 7, no. 6, pp. 419-423, 1999

Authors: Rahman, T. | McClenathan, K.

Article Type: Research Article

Abstract: A force-assist mechanism has been developed to mount on the Chameleon – a wheelchair mounted rehabilitation robot. The device will amplify the forces applied by the user, making it possible to lift a large weight with a small force. This paper describes the test-bed development; instrumentation of the Chameleon with power assistance; and preliminary results on system efficacy.

DOI: 10.3233/THC-1999-7607

Citation: Technology and Health Care, vol. 7, no. 6, pp. 425-429, 1999

Authors: Reinkensmeyer, D.J. | Schmit, B.D. | Rymer, W.Z.

Article Type: Research Article

Abstract: Significant potential exists for mechatronic devices to improve assessment and treatment of individuals with a movement disability following stroke, traumatic brain injury, or cerebral palsy. We report the use of a mechatronic device for evaluation of the arm after chronic brain injury. We performed a series of experiments with the device in order to identify the relative contribution of three different motor impairments to decreased active range of motion of reaching in five brain-injured subjects. Our findings were that passive tissue restraint and agonist weakness, rather than antagonist restraint, were the most common contributors to decreased active range of motion. …These results demonstrate the feasibility of objective assessment of functional movement using a mechatronic device, and could provide the basis for improved, individualized treatment planning and monitoring following brain injury. Show more

DOI: 10.3233/THC-1999-7608

Citation: Technology and Health Care, vol. 7, no. 6, pp. 431-435, 1999

Authors: Mihelj, M. | Matjačić, Z. | Bajd, T.

Article Type: Research Article

Abstract: The study examines postural activity of a constrained subject in response to various disturbances in the sagittal plane. Three different initial standing postures were examined. Each response to a perturbation was divided into three consecutive phases according to the intensity of the muscular activity. The relation of the ankle joint torque versus the ankle joint angle was studied. A linear relationship, resulting in constant ankle stiffness, was observed in each phase of the response. Only negligible differences in the stiffness values were observed among different phases. The results indicate an ankle stiffness value of 10 N m/° for the majority …of initial stance postures and perturbation intensities. Show more

DOI: 10.3233/THC-1999-7609

Citation: Technology and Health Care, vol. 7, no. 6, pp. 437-442, 1999

Authors: Hunt, K.J. | Gollee, H. | Jaime, R. | Donaldson, N.

Article Type: Research Article

Abstract: This paper presents the results of continuing work on feedback control of unsupported standing in paraplegia. Our experimental setup considers a situation in which all joints above the ankle are braced, and stabilising torque at the ankle is generated by stimulation of the plantarflexors. A previous study showed that short periods of unsupported standing with paraplegic subjects could be achieved. In order to improve consistency and reliability of unsupported standing we are currently investigating several modifications to the control strategy. The paper reports progress towards this goal.

DOI: 10.3233/THC-1999-7610

Citation: Technology and Health Care, vol. 7, no. 6, pp. 443-447, 1999