Cost effectiveness and efficiency in assistive technology service delivery.

In order to develop and maintain a viable service delivery program, the realities of cost effectiveness and cost efficiency in providing assistive technology must be addressed. Cost effectiveness relates to value of the outcome compared to the expenditures. Cost efficiency analyzes how a provider uses available resources to supply goods and services. This paper describes how basic business principles of benefit/cost analysis can be used to determine cost effectiveness. In addition, basic accounting principles are used to illustrate methods of evaluating a program's cost efficiency. Service providers are encouraged to measure their own program's effectiveness and efficiency (and potential viability) in light of current trends. This paper is meant to serve as a catalyst for continued dialogue on this topic.

Current status of rehabilitation engineering/technology.

An overview is given of the development of rehabilitation engineering, and the founding of the Rehabilitation Engineering Society of North America (RESNA) is discussed. A listing is given of 16 special interest groups that are in charge of the various scientific, engineering, and technological areas covered by rehabilitation engineering. Current trends in the field are identified.

Computerized data management as an aid to clinical decision making in rehabilitation medicine.

A computerized data-base management system has been developed as a basis for clinical decision making in rehabilitation. The system allows efficient entry, storage, manipulation, and retrieval of patient performance data. With every new entry all previous entries can be displayed. Thus, identification of trends or rapid changes is far easier than perusing data entered into the hospital chart in a conventional way. The system also allows rapid review of all data entries of the entire rehabilitation team by any individual member. Additionally, correlation of variables can be obtained easily. Use of this system facilitates discontinuation of ineffective programs and identification of complications, thereby reducing hospital stay and cost.

Microcomputer-based communication augmentation systems for two nonspeaking, physically handicapped persons with severe visual impairment.

Two different microcomputer-based communication systems were developed for nonspeaking physically handicapped individuals with severe visual impairment. One subject was 24 years old and had an inoperative optic glioma which impaired motor function as well as vision. The second subject was cortically blind with severe motor limitation secondary to an automobile accident which occurred at 17 years of age. Both communication systems employed speech synthesis as a control feature to compensate for visual impairment. Both subjects have learned to use their communication systems. The second subject has not achieved extended, independent system use due to reduced vigilance and attention span.

Heating patterns produced by shortwave diathermy applicators in tissue substitute models.

To be a deep-heating modality, shortwave diathermy applicators have to heat the musculature more than the subcutaneous fat. In this study, commercially available and prototype shortwave diathermy applicators were tested using tissue substitute models which allow rapid thermographic scanning of the initial linear transient temperature rise in the subcutaneous fat and muscle. The specific absorption rates (SAR) of the electromagnetic radiation were calculated throughout the tissues. Great differences were found in the deep-heating capability of these applicators. Some of the applicators heated the subcutaneous fat more than the muscle, while others were more efficient in heating the musculature.

Electrical discontinuity of tissue substitute models at 27.12 MHz.

Tissue-substitute models consisting of layers of synthetic, electrically equivalent subcutaneous fat, muscle, and bone shaped in conformation with the normal anatomy are used for rapid determination of distribution of temperature and specific absorption rate throughout the tissues when exposed to electromagnetic radiation. The surfaces of the bisected models are approximated during a short exposure period, then separated and scanned with a thermograph. A method was developed to eliminate the electrical discontinuity at the bisected surfaces while allowing separation and subsequent thermographic scanning. A thin layer of silk screen wetted with propylene glycol saturated with sodium chloride was used at the fat interface and a 0.9% sodium chloride solution was used to wet the screen at the muscle interface to eliminate electrical discontinuity during exposure to 27.12-MHz diathermy. Tests showed that in the presence of an electrical discontinuity the heating pattern was grossly distorted. With the method used, the electrical discontinuity is minimized and the subsequent thermographic scanning reveals that the heating pattern is equivalent to that of an intact model.

Reducing back displacement in the powered reclining wheelchair.

The powered reclining wheelchair used by quadriplegic and other severely disabled people was studied to determine how the chair could be modified so that repeated recline would not produce shear forces that tend to cause the user to be relocated in the chair, limiting independent functioning. Three modifications of the chair were studied: a freely sliding back, a commercially available powered sliding seat, and 4-bar linkage to hinge the chair back. A counterbalanced, freely sliding back was constructed for testing and was instrumented to measure displacement of the person in the chair during recline. The curves of back displacement vs angle or recline were determined for a sample or 8 quadriplegic subjects. The sliding back mechanism was determined to be impractical for incorporation into current chair designs since it required a heavy, rigid back frame. The sliding seat was found to have limited value since it only slightly decreased the back motion during recline. However, the 4-bar linkage virtually eliminated relative motion between the person's back and the chair back, providing a mechanism for potentially resolving this problem both in new recliner design and for retrofit to existing reclining wheelchairs.

Temperatures in human thighs after hot pack treatment followed by ultrasound.

Temperature distributions were measured in the anterior thigh of human volunteers after preheating with a hot pack followed by ultrasound, a frequently used therapeutic procedure. The skin surface temperature is elevated by this procedure but the highest temperature is still produced at the bone-muscle interface at the end of the treatment session.

Cancer rehabilitation: assessment of need, development, and evaluation of a model of care.

A sample of 805 cancer patients, comparable to but not identical with a national study, was screened to identify: rehabilitation problems encountered at different cancer sites; the need for rehabilitation services; and gaps in the delivery of rehabilitation care. Significant numbers of rehabilitation problems were found that could be improved by rehabilitation care. Psychologic problems were commonly encountered and seemed more severe in patients with physical disabilities; these patients have to make adjustments to both life-threatening disease and to a disabling condition. The findings suggest a need for psychosocial support services on any oncology service; where cancer is associated with significant physical disability, a comprehensive rehabilitation team with psychologic management capability is often needed. Primary barriers to optimal delivery of rehabilitation care are the lack of identification of patient problems and/or lack of appropriate referral by physicians unfamiliar with the concept of rehabilitation. Health care financial support for the patients in the sample came primarily from private insurance, Medicare and Medicaid; financial support from the patient's family held up well even in the advanced stages of the disease. A model of rehabilitation care delivery was established and implemented, with the result being that gaps and barriers to rehabilitation service delivery disappeared rapidly.

Undergraduate education in rehabilitation medicine: trends in curriculum development and the impact on specialty manpower and delivery of service.

One hundred thirteen medical schools which offered full degree programs were identified and surveyed by questionnaires to obtain information which identified the existence, characteristics and involvement of physical medicine or rehabilitation medicine programs. The survey also attempted to identify specific changes which have occurred in undergraduate medical education in rehabilitation medicine since the Commission of Education and Rehabilitation Medicine survey of 1963-64. The results suggest that growth of the programs has not followed the expansion in the number of medical schools nor in the number of students enrolled. The programs have however, improved their administrative standing and involvement in medical schools. The impact on the undergraduate medical student is not satisfactory as judged by elective enrollment and recruiting of residents. Lack of funding was found to be one of the major obstacles to curriculum development, along with a marked shortage of academic physiatrists. The impact of the changes in undergraduate medical school curricula on rehabilitation medicine has produced considerable conjoint teaching in conjunction with a large number of basic science and clinical departments.

Restraining forces in various designs of knee ankle orthoses: their placement and effect on the anatomical knee joint.

A biochemical evaluation was conducted on double upright knee ankle orthoses, which were instrumented with strain gauge transducers to determine the magnitudes of the restraining forces exerted on the leg. Measurements were made on six commonly used designs of orthoses worn by spinal cord injured persons ambulating with a swing-through gait. The measurements were used to determine distribution of forces on the limb as well as their effect on anatomical knee shear. Based on the experimental data, the following basic principles of optimal orthosis design were identified: The forces required to stabilize the knee should be minimized by applying the stabilizing force as close as possible to the knee center, and by maintaining the anatomical knee as straight as possible. When the major portion of the knee stabilizing force is applied below the knee, the shear on the anatomical knee structures is markedly reduced. Further, the stabilizing forces should be well distributed over tolerant areas.

Craig-Scott orthosis: a biochemical and functional evaluation.

The Craig-Scott double upright knee ankle orthosis was subjected to a biomechanical evaluation which included analysis of the force interaction with the supported limb and a functional evaluation. The results were compared with data previously determined from biomechanical evaluations of other common orthoses. In the Craig-Scott design, the single application of the knee stabilizing force below the knee concentrates this force in a relatively small bony area, sometimes exceeding tolerance. This might be avoided by using a tibial closure with patellar tendon bearing features. The design was found to produce relatively low anatomic knee shear. In functional aspects such as donning, doffing, transfers and ambulation, the orthosis is essentially equivalent to other double upright designs. The rigidity of the orthosis with only a tibial band closure and a bail connecting the uprights was determined to be adequate. The limited number of bands and closures provides some advantages in reduced donning and doffing time; however, in the absence of posterior closures below the knee, the orthosis had a tendency to slide forward off the leg when transferring. This disadvantage was eliminated by adding a soft posterior closure below the knee, which produced a minimal increase in donning and doffing times.

Ultrasound coupling media: their relative transmissivity.

The relative transmissivities of several commonly used ultrasonic coupling agents were measured to determine if there were significant differences in their effectiveness. Coupling media were evaluated in thin films to simulate clinical use. In order to minimize experimental error in this determination, transmitted energy was measured in the far field of the sonating transducer; the receiving transducer was angled slightly to minimize standing waves; and the sonating chamber was made as anechoic as possible. It was found that there is no practical difference in the transmissivities of the common coupling agents, except that hydrocortisone ointments and creams had lower transmissivities, probably due to microscopically entrapped air. When used as a thin film, absorption of ultrasound in the media was insignificant, and variation in transducer pressure was found to cause differences in energy transmitted greater than those found between the common coupling media. Consequently, it was concluded that coupling media can be chosen primarily on the basis of cost and convenience.

Heat and stretch procedures: an evaluation using rat tail tendon.

This study evaluated various methods of applying force to collagenous tissue at various temperatures to produce permanent elongation, using rat tail tendon as the tissue model. A materials testing machine was used to measure the forces applied and the resulting elongation produced by differing procedures. Short-term vigorous stretching and prolonged moderate stretching were compared at 37 C. The effect of heating tissue prior to applying force was evaluated, and the effect of using a prolonged application of low force was demonstrated. The data showed that the low force, long duration procedure was very effective at producing residual elongation. Elevating tissue temperature and maintaining it prior to applying force was found to cause significantly less damage; and finally, the lower loads applied at elevated temperatures for prolonged periods were found to produce significantly greater residual elongation.