Preview of Abstracts Fifth Annual Conference of the IEEE Engineering in Medicine and Biology Society

1983 IEEE Transactions on Biomedical Engineering  
The phenomenon and issues associated with the development and clinical utilization of coded scoring sheets (ordinal scale ratings) and instrumented devices to measure the functional level of patients with sensory or motor disorders cut across many scientific disciplines and professions. Basic investigative studies and clinical trials are found in such fields as biomedical engineering, biostatistics, gerontology, industrial and human factors engineering, neurology, personnel management,
more » ... ogy, psychiatry, psychology, psychotherapy, rehabilitation, surgery, and toxicology. Recognizing the importance, pharmaceutical and medical device companies, and health-related regulatory and funding agencies (such as the Food and Drug Administration and the National Institutes for Handicapped Research) are increasingly requiring sensitive, objective, and comprehensive analyses to document changes in function over time. In addition to clinical studies, experimental evaluation studies of test systems are oftentimes carried out to verify such factors as reliability, validity, effects of learning from test repetition, motivation, and the relation of age and gender on normal and abnormal function. The advent of low-cost mini-and microcomputers have already been commercially applied to quantify evoked potentials, EEG, nerve conduction velocity, and EMG, and may soon be used to comprehensively assess such functions as vision, hearing, memory, strength, reactions, steadiness, sensations, speed and coordination movement, stance, gait, range of motion, and activities of daily living. In the process, measurement techniques may become more standardized and widely applied to the mutual benefit of clinicians and investigators in numerous scientific disciplines. This presentation includes a broad review of coded and instrumented tests of function and their applications, an assessment of current status, and a prospectus for future developments. The role of rehabilitation engineering is to enhance handicapped persons' communication, environmental control, mobility, seating, and postural support through the use of technology. An individual's needs and functional capabilities must be carefully assessed in order to provide an effective assistive device or system. The "rehabilitation team" (nurse, occupational therapist, orthotist/prosthetist, physical therapist, physician, rehabilitation engineer, speech pathologist) uses its combined expertise and available evaluation tools to assess the patient's functional capabilities. A few commercial aids and systems currently available have "evaluation systems" which can be used to determine feasibility for an individual and optimal system configuration. A thorough knowledge of commercial devices and techniques for their modification, as well as the ability to develop custom devices, are used to match a handicapped person's needs and functional capabilities with an appropriate aid. It is the obligation of the rehabilitation team to take cost, durability, and serviceability into consideration in choosing a technological aid. Examples of patient evaluations are presented, and the need for generalized assessment systems is discussed. The more severe the physical handicap, the greater the need for detailed, quantitative information on the individual. The Louisiana Tech Rehabilitation Engineering Research, Development and Training Center has performed research directed at the development of a series of activity-oriented functional assessments to assist the moderate-toseverely physically handicapped person. These computer-aided assessments are directed at three major areas (work, independent living, driving) and complement existing assessment and evaluation services available to this population. An interdisciplinary team approach (including engineers, physicians, therapists, rehabilitation counselors, and driving specialists) was utilized. Since the Center houses a resident dormitory for the moderate-to-severely handicapped, the user population had the opportunity to actively participate in their development. Over the past ten years, the technologic development of powered prosthetic arms has proceeded at a rapid pace. Unfortunately, relatively little attention or resources have been directed at developing methods to train individuals fitted with these devices. As a result, acceptance of multiple degree-of-freedom devices by amputees has been disappointingly low. At the present time, few clinics will fit high level or bilateral amputees with devices designed to (theoretically) provide a wide range of motion. A study was undertaken with a high level, bilateral amputee who had received two myoelectrically controlled prosthetic arms to identify methods of training him to control a total of five degrees-of-freedom. These five degrees-of-freedom are controlled 494 IEEE TRANSACTIONS ON BIOMEDICAL ENGINEERING, VOL. BME-30, NO. 8, AUGUST 1983 by eight different electromyographic recording sites and one mechanical switch. The subject was first trained to isolate individual muscles using visually displayed EMG signals. Using goniometry at each powered joint, the subj&ct next learned to track visually displayed waveforms with each joint. Finally, multiple joint movements were learned in which all joints moved simultaneously. These training methods were developed specifically to 1) produce natural looking motion, 2) with a minimum of visual attention to the arm itself, and 3) with hardware which could be used in an "in-home" setting. Arlington, TX 76079 Human muscle function and fatigue during exercise can be quantified using measures of the frequency power spectrum of the myoelectric signal. By computing the mean and median power frequencies (MPF and MDPF, respectively) and total signal power (rms voltage) of the myoelectric signal spectrum using digital signal processing techniques, correlations between these variables and muscle force, endurance time, and fatigue can be evaluated. Myoelectric signals obtained from erector spinae and rectus abdominis muscles during isometric exercise were digitized and stored on a DEC LSI-l 1/23 minicomputer. A 512 point fast Fourier transform was used to obtain an averaged periodogram, from which MPF, MDPF, and. total signal power for the frequency band of 12-512 Hz were obtained. F'atigue time constants derived from MPF changes over time showed positive correlations with endurance time (r = 0.88) and positive test-retest reproducibility (r = 0.79). This paper describes a syntactic pattern recognition method for the evaluation of abnormalities in human gait. One essential prerequisite for detecting abnormalities is the existence of a description of the normal characteristics of gait. The system constructed in this research contains a normative database which includes conventional descriptive terms such as swing, stance, degree of flexion, etc., and information derived from the electromyogram (EMG), foot-contact patterns, and kine-Microwave-induced thermoelastic pressure waves appear to possess some unique features that may allow themn to become as useful as other imaging methods and permit noninvasive imaging of tissue characteristics which are not identifiable by other techniques. In this paper, we present a system design of microwave-induced thermoelastic tissue imaging along with an example which demonstrates the feasibility of the design approach. A brief burst of microwave pulses generates either deep or superficial, wide-area acoustic illumination according to a selected Microwave absorption pattern. An array of 20 X 20 hydrophone transducers are used to detect the thermoelastic pressure waves. The received signal is amplified, bandlimited, filtered, and digitally processed to produce thermoelastic images of the irradiated body region. A theoretical signal-to-noise ratio calculation is included. Different design approaches for data acquisition are discussed. A parallel design is the most efficient, but it is also the most expensive one. A serial design is limited by present technology. A hybrid parallel/serial design of dividing the 20 X 20 array into segments and collecting data from rh segment sequentially is suggested. This design gives good picture qality with reasonable cost, provided the object is quasistationary. First, for the purpose of establishing a common level, a brief introduction will be provided to the basic concepts involved in nuclear magnetic resonance (NMR) imaging. Aspects to be reviewed will include the quantum mechanical foundations of NMR, magnetization in a rotating frame, the macroscopic equations of motion (Bloch equations), relaxation parameters (Tl, T2), and the principle of magnetic field gradient imaging. A functional description of the basic NMR spectrometer will be provided including aspects of pulse programmer protocols, quadrature detection, Fourier transform techniques, and microcomputer control and processing of NMR signals. Aspects of the design and technology of whole body magnet systems options, radio frequency coils, and gradient coils for NMR imaging systems will be presented. In NMR imaging, a radio frequency (RF) pulse in the presence of static magnetic field gradients is used to select the region from which the NMR signal is obtained. The design of selective pulses is important as it controls the resolution of the NMR imaging. In this paper, we evaluate the effect of amplitude modulation of the RF pulse on the spatial distribution of the spin magnetization [M(x)]. The Bloch equations which describe the behavior of M(x) in the presence of the RF pulse have time-varying coefficients, and closed form solutions cannot be obtained. We have used numerical integration of Bloch equations to study the relationship between the shape of the pulse, its frequency spectrum, and M(x). The rectangular, triangle, Hanning, and Gaussian pulse shapes have been compared. A discrete-time, lumped parameter mathematical model of the human cardiopulmonary circulation as it appears during a first-transit radionuclide study has been developed. The model consists of 11 chambers, four delays, and 26 transfer paths including forward and reverse flow through the heart valves, backflow from the atria into the veins, and five types of shunts. The specifics of this paper flow from the long-range objective to develop a completely implantable TAH system. The current work addresses two questions. First, what is the best control algorithm for a TAH configured out of existing energy converters and the CCF biolized pusher plate pump? Second, is it possible to broaden the scope of this
doi:10.1109/tbme.1983.325152 fatcat:5ytnmjovmbbexh2nd7x322enge