Assessing the influence of wheelchair technology on perception of participation in spinal cord injury11No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit upon the author(s) or upon any organization with which the author(s) is/are associated

OBJECTIVE

To investigate factors related to the wheelchair, impairment, and environment that affect perception of participation of persons with spinal cord injury (SCI) in activities performed in 3 settings: in the home, in the community, and during transportation.

DESIGN

Cross-sectional study.

SETTING

Research centers and a specialized assistive technology (AT) clinic in Pittsburgh (Pitt). Research centers and community-based rehabilitation technology suppliers in Saint Louis (SL).

PARTICIPANTS

Seventy wheelchair users with SCI.

INTERVENTIONS

Subjects from Pitt and SL completed a written survey of AT usage in daily activities.

MAIN OUTCOME MEASURES

Subjects were asked 5 questions within each setting (home, community, transportation) related to their perceived reason for functional limitations.

RESULTS

The wheelchair was the most commonly cited factor limiting participation, followed by physical impairment and physical environment. Twenty-one percent of subjects with paraplegia reported pain as a limiting factor for their transportation use, significantly more (P=.047) than subjects with tetraplegia (3%). A trend (P=.099) was seen toward a higher percentage of subjects with tetraplegia (tetraplegia, 7%; paraplegia, 3%) reporting lack of equipment as a limiting factor for use of transportation. Differences were also seen across sites.

CONCLUSIONS

The wheelchair was the most commonly cited limiting factor, followed by physical impairment and physical environment. The wheelchair is the most important mobility device used by persons with SCI and the one that users most associate with barriers.

Evaluation of a pushrim-activated, power-assisted wheelchair

OBJECTIVE

To evaluate a novel pushrim-activated, power-assisted wheelchair (PAPAW) for compliance with wheelchair standards, metabolic energy cost during propulsion, and ergonomics during selected activities of daily living (ADLs).

DESIGN

A 3-phase study, the second and third of which were repeated-measures designs.

SETTING

A rehabilitation engineering center within a Veterans Affairs medical center.

PATIENTS

Eleven full-time, community-dwelling, manual wheelchair users (4 women, 6 men) with spinal cord injuries or multiple sclerosis.

INTERVENTIONS

Phase 1: Compliance testing, with a test dummy, in accordance with the wheelchair standards of the American National Standards Institute and the Rehabilitation Engineering and Assistive Technology Society of North America. Phase 2: Metabolic energy consumption testing-at 2 speeds and 3 resistance levels-in subjects' manual wheelchair and the PAPAW. Phase 3: Evaluation of ability to perform ADLs and ergonomics of the PAPAW compared with the subjects personal wheelchair.

MAIN OUTCOME MEASURES

Phase 1: The PAPAW's static stability, static strength, impact strength, fatigue strength, environmental response, obstacle climbing ability, range, maximum speed, and braking distance. Phase 2: Subjects' oxygen consumption per minute, minute ventilation, and heart rate during different speeds and workloads with a PAPAW and their own wheelchairs. Phase 3: Subject ratings of perceived comfort and basic ergonomics while performing selected ADLs. Completion time, stroke frequency, and heart rate during each ADL.

RESULTS

Phase 1: The PAPAW was found to be in compliance with wheelchair standards. Phase 2: With the PAPAW, the user had a significantly lower oxygen consumption (&Vdot;O(2)mL/min: p <.0001; &Vdot;O(2)mL/kg x min: p <.0001) and heart rate (p <.0001) when compared with a manual wheelchair at different speeds. Phase 3: The PAPAW had a significantly higher mean ergonomic evaluation (p <.01) than the subjects' personal wheelchairs. The results of comparing the ratings of the car transfer between the PAPAW and the subjects' personal wheelchair showed a significant difference in the task of taking the wheels off (p <.001) and putting the wheels back on (p =.001), with the PAPAW receiving lower ratings.

CONCLUSION

This study indicated that the PAPAW is compliant with wheelchair standards, reduces the energy demand placed on the user during propulsion, and that subjects rated its ergonomics favorably when compared with their personal wheelchair. PAPAWs may provide manual wheelchairs with a less physiologically stressful means of mobility with few adaptations to the vehicle or home environment.

Submaximal physical strain and peak performance in handcycling versus handrim wheelchair propulsion

STUDY DESIGN

Experimental study in subjects with paraplegia and nondisabled subjects.

OBJECTIVE

To compare submaximal physical strain and peak performance in handcycling and handrim wheelchair propulsion in wheelchair-dependent and nondisabled control subjects

SETTING

Amsterdam, The Netherlands.

METHODS

Nine male subjects with paraplegia and 10 nondisabled male subjects performed two exercise tests on a motor-driven treadmill using a handrim wheelchair and attach-unit handcycle system. The exercise protocol consisted of two 4-min submaximal exercise bouts at 25 and 35 W, followed by 1-min exercise bouts with increasing power output until exhaustion.

RESULTS

Analysis of variance for repeated measures showed a significantly lower oxygen uptake (VO2), ventilation (Ve), heart rate (HR), rate of perceived exertion and a higher gross efficiency for handcycling at 35 W in both subject groups, while no significant differences were found at 25 W. Peak power output and peak VO2, Ve and HR were significantly higher during handcycling in both groups. The differences between handcycling and wheelchair propulsion were the same in subjects with paraplegia and the nondisabled subjects.

CONCLUSIONS

Handcycling induces significantly less strain at a moderate submaximal level of 35 W, and shows noticeably higher maximal exercise responses than wheelchair propulsion, which is consistent in subjects with paraplegia and nondisabled controls. These results demonstrate that handcycling is beneficial for mobility in daily life of wheelchair users.

Performance of selected lightweight wheelchairs on ANSI/RESNA tests. American National Standards Institute-Rehabilitation Engineering and Assistive Technology Society of North America

OBJECTIVE

This study provides data for clinicians and wheelchair users to compare the durability, stability, and cost effectiveness of three different lightweight wheelchair models: the Everest & Jennings EZ Lite, the Invacare Rolls 2000, and the Quickie Designs Breezy. A second objective was to compare the results from this study to those published for ultralight and institutional depot wheelchairs.

DESIGN

Randomized standards testing of three wheelchair models from each manufacturer (nine wheelchairs total).

RESULTS

There were no significant differences (p > .05) in fatigue life, life-cycle cost, or static stability between the three models of lightweight wheelchairs (ie, EZ Lite, Rolls 2000, or Breezy). There were, however, significant differences (p < .05) in fatigue life among the lightweight wheelchairs of this study and the published results for ultralight rehabilitation wheelchairs and for depot wheelchairs. The lightweight wheelchairs had an average fatigue life greater than the depot wheelchairs but less than the rehabilitation wheelchairs. A depot-type wheelchair was defined as a manual wheelchair designed for hospital or institutional use. At lightweight wheelchair was defined as a manual wheelchair with minimal adjustments designed for individual or institutional use. An ultralight rehabilitation wheelchair was defined as a manual wheelchair designed for an individual's use as a long-term mobility aid.

CONCLUSION

The three models of lightweight wheelchairs tested are substantially similar and their fatigue lives are significantly (p < .05) lower than rehabilitation wheelchairs. Ultralight rehabilitation wheelchairs are the most cost effective over the life of the wheelchair, costing 3.4 times less (dollars per life cycle) than depot wheelchairs, and 2.3 times less (dollars per life cycle) than the lightweight wheelchairs tested in this study.

Comparison of fatigue life for 3 types of manual wheelchairs

OBJECTIVES

To examine 3 types of manual wheelchairs-ultralight wheelchairs (UWs), lightweight wheelchairs (LWs), and depot wheelchairs (DWs)-and to compare the fatigue life between the wheelchair types.

DESIGN

A database of different manual wheelchairs tested according to the International Organization for Standardization (ISO). Fatigue life was determined by using standards that define methods accepted internationally using double-drum and curb-drop testing equipment.

SETTING

A rehabilitation engineering center.

SPECIMENS

Sixty-one manual wheelchairs: 25 DWs, 22 UWs, and 14 LWs.

MAIN OUTCOME MEASURES

Wheelchairs were examined for differences in fatigue life based on equivalent cycles. Unique survival curves were fit and compared for each wheelchair type.

RESULTS

The UWs lasted the longest, with a mean of 309,362 equivalent cycles. The DWs faired the worst, with a mean of 117,210 equivalent cycles. The Kaplan-Meier survival curves were significantly different (p < .001), with the UWs having the longest fatigue life.

CONCLUSION

Fatigue life for UWs is significantly greater (p < .05) than LWs and DWs, indicating wheelchairs differ in durability.

The effect of wheelchair handrim tube diameter on propulsion efficiency and force application (tube diameter and efficiency in wheelchairs)

To determine the optimum tube diameter of a standard handrim-propelled wheelchair, the effect of tube size and shape on physiological and kinetic parameters was studied. Six able-bodied male subjects performed two tests on a wheelchair ergometer. Tests were performed against work loads comparable to every day use and with two different handrim tube diameters, a handrim with an oval 25 by 30 mm diameter (LR) and one with an 18 mm diameter (SR). The large tube diameter (LR) yielded slightly but significantly lower values for the physiological parameters. Gross mechanical efficiency was on average 7% for the LR and 6.3% for the SR. No significant results were found for force application parameters related to the direction of the applied force or the torque by the hand onto the handrim surface. As technique parameters could not explain the higher mechanical efficiency (ME) when using the LR, it is suggested that hand grip constraints in the push phase (finger flexor activity) might be responsible. Another possible explanation is that with a better hand grip using LR, less stabilization by the larger muscle groups at the elbow and shoulder is needed. The measured technique parameters seem to be determined by geometric constraints of the arm and shoulder. The technique requirements resulting from the forced trajectory of the propulsion movement are also likely to determine the technique parameters. Regarding the low mechanical efficiency of handrim propulsion, which is partly caused by the forced unfavorable trajectory of the hand, an alternative propulsion mechanism is suggested.

Wheelchair racing sports science: a review

Wheelchair racing science and the performance of athletes involved in wheelchair racing have developed rapidly in recent years. With increasing interest in this sport, the need arises to identify areas where further research is necessary and cooperation between individuals with various backgrounds is encouraged. Many of the problems facing investigators in this field require knowledge in several areas of science and engineering, which suggests an interdisciplinary approach to these issues. Further progress would also benefit from the development of more quantitative methods for the classification of wheelchair athletes, or a restructuring of the classification system; development of sophisticated instrumentation for racing wheelchairs; standardization of test procedures and more complete reporting of results of studies; and, more in-depth mathematical modelling and computer simulation of wheelchair racing. This review presents an overview of four areas of wheelchair racing science: 1) classification of wheelchair athletes; 2) design and analysis of racing wheelchairs; 3) biomechanics of racing wheelchair propulsion; and, 4) training and coaching of wheelchair racers.

Pediatric Powered Wheelchairs: Results of a National Survey of Providers

A national survey of providers of pediatric powered wheelchairs was conducted to collect background data on these professionals and to develop a "model" of their current assessment and recommendation practices. Data collected in the survey included provider demographics, frequency of powered wheelchair provision to young children, common reasons for not recommending a powered wheelchair, reasons why a child who is recommended a powered wheelchair does not receive one, current pediatric powered wheelchair assessment and recommendation practices, and subjective data regarding the efficacy of these practices and the impact of powered wheelchairs on children. Respondents rated the frequency with which they performed various wheelchair assessment and recommendation practices, and these ratings were analyzed to determine activities that were performed frequently. These activities were then combined into common "factors" using factor analysis, and the results of the factor analysis were used to create a model of current pediatric powered wheelchair assessment and recommendation practices. A total of 140 surveys were received from providers in 46 states. Of these providers, 54% were clinicians (e.g., physical therapists, occupational therapists), and 46% were suppliers (e.g., Rehabilitation Technology Specialists), representing a variety of geographic locations and facility types. The 3 major reasons for not recommending a powered wheelchair included cognitive, physical, and behavioral factors. The 3 major reasons why a child who is recommended a powered wheelchair does not receive one included funding issues, lack of family support, and transportation issues. The model of current pediatric powered wheelchair provision includes 4 assessment factors: Preliminary Clinical Assessment, Intake, Advanced Clinical Assessment, and Consideration of Other Factors. Typical recommendations include both therapeutic and nonclinical interventions. A modified version of this model, which addresses some issues identified in the survey that limit wheelchair recommendations, is currently being tested at 4 clinical sites.

Evaluation of selected ultralight manual wheelchairs using ANSI/RESNA standards

OBJECTIVES

To provide data for clinicians and wheelchair users to compare the durability, strength, stability, and cost effectiveness of four different ultralight wheelchair models, and to compare the results of this study with those published for lightweight wheelchairs.

DESIGN

Standards testing and cost-effectiveness analysis of four wheelchair models from different manufacturers (12 wheelchairs total).

RESULTS

There were significant differences (p< or =.05) in the fatigue life and value (equivalent cycles per dollar) among the ultralight wheelchairs tested. There was also a significant difference (p< or =.05) in rearward stability tilt angle for the least and most stable configurations. There were no differences in forward and lateral stability. The ultralight wheelchairs (1,009,108 cycles) had significantly (p< or =.05) higher fatigue lives than previously reported for lightweight wheelchairs (187,370 cycles). The lightweight wheelchairs had a mean value of 210 cycles per dollar compared to 673 cycles per dollar for the ultralight wheelchairs. The difference in value for the lightweight and ultralight wheelchairs was statistically significant (p< or =.05).

CONCLUSION

There were differences in the fatigue life and value among the four models of ultralight manual wheelchairs tested. This indicates that ultralight manual wheelchairs are not all of equal quality. The fatigue life and value of the ultralight manual wheelchairs were significantly higher than those previously reported for lightweight manual wheelchairs. This indicates that ultralight wheelchairs may be of higher quality than lightweight manual wheelchairs. Clinicians and consumers should seriously consider selecting an ultralight manual wheelchair to meet their wheelchair mobility needs.

Demographic and socioeconomic factors associated with disparity in wheelchair customizability among people with traumatic spinal cord injury

OBJECTIVES

To determine if a standard of care for wheelchair provision exists within the participating centers and if there is disparity in wheelchair customizability among the study sample.

DESIGN

Convenience sample survey.

SETTING

Thirteen Model Spinal Cord Injury Systems that provide comprehensive rehabilitation for people with traumatic spinal cord injury (SCI) and that are part of the national database funded through the US Department of Education.

PARTICIPANTS

A total of 412 people with SCI who use wheelchairs over 40 hours a week.

INTERVENTION

Survey information was obtained from subjects via telephone and in-person interviews and from the national database. Collected information included age, race, education, level of injury, and wheelchair funding source.

MAIN OUTCOME MEASURES

Number and type (manual or power) of wheelchairs. Wheelchair customizability as defined by design features (eg, adjustable axle position, programmable controls).

RESULTS

Ninety-seven percent of manual wheelchair users and 54% of power wheelchair users had customizable wheelchairs. No power wheelchair user received a wheelchair without programmable controls. Minorities with low socioeconomic backgrounds (low income, Medicaid/Medicare recipients, less educated) were more likely to have standard manual and standard programmable power wheelchairs. Older subjects were also more likely to have standard programmable power wheelchairs.

CONCLUSIONS

The standard of care for manual wheelchair users with SCI is a lightweight and customizable wheelchair. The standard of care for power wheelchairs users has programmable controls. Unfortunately, socioeconomically disadvantaged people were less likely to receive customizable wheelchairs.

Initial results in the development of a guidance system for a powered wheelchair

This paper describes the development of an automatically guided powered wheelchair for individuals with severe disabilities. The navigation and control of the wheelchair is based the accurate estimation of the location of the wheelchair within its operating workspace. A novel method used to generate and track reference paths which take the user to and from various destinations within the wheelchair's environment is presented. The paper also provides a qualitative description of the restrictions and requirements that are specific to the wheelchair application as well as the way in which the current system addresses these restrictions and requirements. Finally, actual experimental runs of the wheelchair system are presented.

Performance diagnostics in handbiking during competition

STUDY DESIGN

Case study in handbiking under competition conditions.

OBJECTIVE

To investigate exercise-induced, metabolic, pulmonary, cardiovascular and energetic reactions of a paraplegic athlete during a city marathon.

SETTING

City marathon Cologne, Germany.

SUBJECT

We tested a 27-year-old male athlete from the German national team. The handicap of the athlete was a complete traumatic spinal cord injury ASIA/IMSOP Grade A at the level of the fourth thoratic vertebra (Th4).

METHOD

In the competition, the athlete used his own race handbike whose crank system had been exchanged for a power measurement system with registering option. For measuring ventilatory gas parameters during exercise, a portable spirometric system was used. The athlete managed to finish the marathon race in 1:48:54 h.

RESULTS

The mean oxygen uptake (VO2) during the marathon was 1580 ml/min, with a maximum value of 2535 ml/min. The mean heart frequency was 137 bpm with a maximum of 157 bpm. During the race the mean energy consumption was 463 kcal/h with a maximum of 758 kcal/h. Prior to the race, the blood lactate value was 2.9 mmol/l; after 10 km 4.4 mmol/l; after 20 km 2.9 mmol/l, and after 30 km 2.9 mmol/l.

CONCLUSION

Competition-oriented handbikers should concentrate on exercise units of long duration at low intensities--like marathon runners or cyclists--in order to improve their aerobic performance capacity. However, it has to be pointed out that paraplegic athletes develop relatively high metabolic intensities in competition and that the variability of their physiological parameters is considerably high.

Powered Tilt/Recline Systems: Why and How Are They Used?

Prolonged static sitting can lead to discomfort, pain, pressure sores, spinal curvatures, and loss of functional independence. In order to counteract these harmful effects, adjustable tilt and/or recline systems are often prescribed. Considering the current context of assistive technology service delivery and budget cuts, it is essential to have a better knowledge of the use of these technical aids and user's satisfaction with them. The purpose of this study was to characterize the use of powered tilt and recline systems. A questionnaire was developed for this purpose, and 40 subjects were interviewed at home. They were asked to identify, from a list of 25 objectives, the reasons for which they used their repositioning system and to rank these reasons in order of importance. For each objective, they were also asked to identify the frequency and range of use as well as their satisfaction level with their system. Results revealed that 97.5% of the subjects were using their powered tilt and recline system everyday, and their satisfaction was high. The main objectives for using this type of assistive technology were to increase comfort and to promote rest. Although mainly descriptive, results are of clinical relevance and can be helpful when selecting wheelchairs.

Impact of a pushrim-activated power-assisted wheelchair on the metabolic demands, stroke frequency, and range of motion among subjects with tetraplegia

OBJECTIVES

To determine differences in metabolic demands, stroke frequency, and upper-extremity joint range of motion (ROM) during pushrim-activated power-assisted wheelchair (PAPAW) propulsion and traditional manual wheelchair propulsion among subjects with tetraplegia.

DESIGN

Repeated measures.

SETTING

A biomechanics laboratory within a Veterans Affairs medical center.

PARTICIPANTS

Fifteen full-time manual wheelchair users who had sustained cervical-level spinal cord injuries.

INTERVENTIONS

Participants propelled both their own manual wheelchairs and a PAPAW through 3 different resistances (slight, 10W; moderate, 12W; high, 14W) on a wheelchair dynamometer. Each propulsion trial was 3 minutes long.

MAIN OUTCOME MEASURES

Primary variables that were compared between the 2 wheelchairs were participants mean steady-state oxygen consumption, ventilation, heart rate, mean stroke frequency, and maximum upper-extremity joint ROM.

RESULTS

When using the PAPAW, participants showed a significant ( P <.05) decrease in mean oxygen consumption and ventilation throughout all trials. Mean heart rate was significantly lower when using the PAPAW for the high resistance trial. Stroke frequency was significantly lower when using the PAPAW for the slight and moderate resistances. Overall joint ROM was significantly lower when using the PAPAW.

CONCLUSIONS

For subjects with tetraplegia, PAPAWs reduce the energy demands, stroke frequency, and overall joint ROM when compared with traditional manual wheelchair propulsion.

Engineering manual and electric powered wheelchairs

The sophistication required to develop and properly configure a wheelchair is illustrated by the amount and complexity of the research being conducted. At this time there appears to be between 1.5 and 2.0 million full-time wheelchair users within the United States. The reliance of the user on the wheelchair and the amount of time in the wheelchair provide significant challenges for the wheelchair design engineer. Currently there are a wide variety of wheelchair designs that are commercially available. These wheelchairs accommodate a variety of people's needs, and represent significant progress. The current trend among manufacturers of manual wheelchairs seems to be cost-reduction engineering. The ergonomics of long-term wheelchair use are critical to the advancement of wheelchair design and to the clinical selection of wheelchairs. Electric powered wheelchairs appear to be progressing faster than nearly all other types of wheelchairs. This is due to the availability of computing power with low cost microcontrollers and associated peripherals. The greater range and availability of sensors are also making changes into the design of electric powered wheelchairs. The interaction between an electric powered wheelchair and the user can be extremely complex. In many cases, individual solutions are necessary. One of the more challenging questions is determining the abilities of the user required to drive an electric powered wheelchair effectively. There have been substantial improvements in the engineering of all wheelchairs. However, there remain significant issues to be addressed.

Fewer accidents and better maintenance with active wheelchair check-ups: a randomized controlled clinical trial

OBJECTIVE

To investigate whether active intervention using a compiled checklist for wheelchair check-ups increases user satisfaction and/or decreases accidents, near accidents and pressure sores.

DESIGN

A randomized controlled trial comparing active intervention versus standard intervention for prescribed, manually propelled wheelchairs.

SETTING

Patients within primary health care of Borås and Bollebygd municipalities, a mixed urban and rural population.

SUBJECTS

Users of manually propelled wheelchairs over 16 years of age.

INTERVENTIONS

The accident rate, extent of pressure sores, number and extent of repairs, reconditioning, adjustments as well as user satisfaction were measured initially and at one year. In the standard intervention, the user and carer were encouraged to initiate contact when necessary. In the active intervention, an occupational therapist performed a scheduled, thorough check-up of the wheelchair, following a compiled checklist for safety, comfort and positioning, manoeuvrability and transportation.

RESULTS

Of 253 registered wheelchair users, 216 were suitable and randomized. In the active intervention group, 99% (95% confidence interval 96-100%) of the inspected wheelchairs required maintenance. The incidence of accidents was unchanged in the standard intervention group, but decreased to 'no accidents' in the active intervention group (p = 0.03). User satisfaction was not affected by the active intervention.

CONCLUSION

Most wheelchair users are unable to determine on their own when adjustments are needed. An active check-up on manually propelled wheelchairs seems to reduce accidents. More information is available at http://www.wheelchair.se

Issues in maintenance and repairs of wheelchairs: A pilot study

In this pilot study, we assessed wheelchair durability and its effect on user satisfaction. Specifically, we examined the characteristics of the participants' wheelchairs, the types of maintenance and repairs completed, and whether the participants' satisfaction was affected by problems with their wheelchairs. A convenience sample of 130 participants who used wheelchairs as their primary means of mobility was recruited. Participants completed a questionnaire about their wheelchairs, the maintenance and repair history, and their satisfaction levels. Results showed that 26% of the participants had completed a wheelchair repair in the past 6 months, 16% had completed general maintenance, and 27% had completed tire repairs. Neither hours of wheelchair use nor wheelchair age affected repair or maintenance frequency. Participants were generally satisfied with their wheelchairs. Better understanding of wheelchair maintenance and repair issues will guide improvements in wheelchair design and enhance the community participation of individuals who use wheelchairs.

Outcomes of wheelchair systems intervention with residents of long-term care facilities

This pilot study was designed to measure the effects of individually prescribed wheelchair systems on posture and reach, mobility, quality of life, and satisfaction with technology for residents of long-term care facilities. Thirty persons 60 years of age or older who resided permanently in a long-term care facility and who used seating and mobility systems for 6 hours or more each day were recruited for this project. Outcomes included timed independent mobility, forward and lateral reach, quality of life, and satisfaction with assistive technology. The study used semicrossover design with participants measured three times. Measurements were first made in the existing seating and mobility system and a second time immediately after participants were provided with individually prescribed seating and mobility systems. The final measurement was 3 months after the delivery of the individually prescribed system. Results indicated that individually fitted wheelchair systems for elderly residents of long-term care facilities are beneficial. Participants had less difficulty independently propelling their systems and increased forward reach, quality of life for social function and physical role, and satisfaction with the new wheelchair technology. Persons residing in extended care facilities benefit from receiving individually prescribed wheelchair systems. The individual systems enhance elderly persons' independent mobility, functional reach, feeling of well-being, and satisfaction with their assistive technology.

Overarching principles and salient findings for inclusion in guidelines for power mobility use within residential care facilities

Although power mobility has many potential benefits for users, power mobility incidents and accidents are a serious concern. To date, little research has explored power mobility safety, and no gold standard exists to determine whether the user is a safe driver. As a possible alternative to a facility unilaterally imposing regulations on power mobility users, we conducted a research project in which power mobility users and other stakeholders used the Delphi method to develop guidelines for power mobility use within a residential facility setting. This article presents the overarching principles for power mobility use and noteworthy items from the safety guidelines that participants developed. These findings highlight the safety issues that are encountered in residential care settings and suggest some strategies to deal with them.

Durability, value, and reliability of selected electric powered wheelchairs11No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit upon the author(s) or upon any organization with which the author(s) is/are associated

OBJECTIVE

To compare the durability, value, and reliability of selected electric powered wheelchairs (EPWs), purchased in 1998.

DESIGN

Engineering standards tests of quality and performance.

SETTING

A rehabilitation engineering center.

SPECIMENS

Fifteen EPWs: 3 each of the Jazzy, Quickie, Lancer, Arrow, and Chairman models.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Wheelchairs were evaluated for durability (lifespan), value (durability, cost), and reliability (rate of repairs) using 2-drum and curb-drop machines in accordance with the standards of the American National Standards Institute and Rehabilitation Engineering and Assistive Technology Society of North America.

RESULTS

The 5 brands differed significantly (P<or=.05) in durability, value, and reliability, except in terms of reliability of supplier repairs. The Arrow had the highest durability, value, and reliability in terms of the number of consumer failures, supplier failures, repairs, failures, consumer repairs and failures, and supplier repairs and failures. The Lancer had the poorest durability and reliability, and the Chairman had the lowest value. K0014 wheelchairs (Arrow, Permobil) were significantly more durable than K0011 wheelchairs (Jazzy, Quickie, Lancer). No significant differences in durability with respect to rear-wheel-drive (Arrow, Lancer, Quickie), mid-wheel-drive (Jazzy), or front-wheel-drive (Chairman) wheelchairs were found.

CONCLUSIONS

The Arrow consistently outperformed the other wheelchairs in nearly every area studied, and K0014 wheelchairs were more durable than K0011 wheelchairs. These results can be used as an objective comparison guide for clinicians and consumers, as long as they are used in conjunction with other important selection criteria. Manufacturers can use these results as a guide for continued efforts to produce higher quality wheelchairs. Care should be taken when making comparisons, however, because the 5 brands had different features. Purchased in 1998, these models may be used for several more years. In addition, problem areas in these models may still be present in newer models.

A technique for the determination of center of gravity and rolling resistance for tilt-seat wheelchairs

A balance platform setup was defined for use in the determination of the center of gravity in the sagittal plane for a wheelchair and patient. Using the center of gravity information, measurements from the wheelchair and patient (weight, tire coefficients of friction), and various assumptions (constant speed, level-concrete surface, patient-wheelchair system is a rigid body), a method for estimating the rolling resistance for a wheelchair was outlined. The center of gravity and rolling resistance techniques were validated against criterion values (center of gravity error = 1 percent, rolling resistance root mean square error = 0.33 N, rolling resistance Pearson correlation coefficient = 0.995). Consistent results were also obtained from a test dummy and five subjects. Once the center of gravity is known, it is possible to evaluate the stability of a wheelchair (in terms of tipping over) and the interaction between the level of stability and rolling resistance. These quantitative measures are expected to be of use in the setup of wheelchairs with a variable seat angle and variable wheelbase length or when making comparisons between different wheelchairs.

Wheelchair cushions for persons with spinal cord injury: an update

Occupational therapists frequently prescribe wheelchair cushions to reduce the risk of pressure sores in patients with spinal cord injury. In an earlier study (Garber, 1985b), Roho cushions were prescribed for the greatest number of subjects studied. The present study of 197 subjects updates these data and describes current prescription patterns, the use of cushions over time, satisfaction with prescribed cushions, and the occurrence of pressure sores with prescribed cushions. The study shows that the Jay cushion was prescribed most frequently for the current subjects, although it was not recommended for all persons with spinal cord injury. In the second phase of the present study, involving 30 subjects, 30% of the subjects discontinued use of the prescribed cushion. Skin breakdown and the discovery of alternative solutions were given as primary reasons. There was no significant difference in the incidence of pressure sores between subjects who continued to use their prescribed cushions and those who did not. This research supports the conclusion of earlier studies that no one wheelchair cushion is universally effective for all persons and that individual evaluation and routine reassessment are essential in reducing the occurrence of pressure sores.

Applied physiology for wheelchair design

The purpose of this study was to evaluate potential wheelchair design changes that may reduce operational energy cost and cardiopulmonary responses. Design changes, which were simulated with a wheelchair ergometer, allowed two techniques of hand-rim propulsion: the usual synchronous application of force (sync), and an asynchronous technique where force was applied one hand at a time in a reciprocal fashion (async). Three hand-rim drive ratios were also simulated: low, normal, and high. Combinations of these force application-drive ratio simulations were evaluated at power output (PO) levels of 30 and 60 kpm.min-1. The async-high combination was found to elicit significantly lower (P less than 0.01) gross caloric output, pulmonary ventilation, and heart rate values, and provide the greatest advantage over conventional sync-normal operation at both PO levels. It appeared that async propulsion and high drive ratio resulted in less wasted movements. Although the async-high combination was superior under these test conditions, other combinations may be necessary to better match various locomotive tasks to individuals of different capabilities.

The effect of walking with an assistive device and using a wheelchair on school performance in students with myelomeningocele

An alternating-condition, single-subject research design was used to examine the effect of ambulation on three measures of school performance in three students with myelomeningocele. The subjects, aged 9, 10, and 15 years, had a physiological cost index greater than 1.00 beats per meter when walking with crutches or a walker. Subjects propelled a wheelchair at school for 5 days, ambulated with crutches or a walker for 5 days, and propelled a wheelchair for an additional 5 days. Performance in reading fluency, visuomotor accuracy, and manual dexterity was assessed at the end of each school day. Results were graphed and analyzed using the two-standard-deviation band method. All subjects had significantly lower visuomotor accuracy scores during the assistive-device ambulation phase than during the wheelchair phases. Performance in manual dexterity during the assistive-device ambulation and wheelchair phases varied among the subjects. Reading fluency was not affected by method of mobility. The results suggest that the high energy cost of walking may have a negative effect on certain aspects of the subjects' school performance. [Franks CA, Palisano RJ, Darbee JC. The effect of walking with an assistive device and using a wheelchair on school performance in students with myelomeningocele.

Wheelchair sports medicine

Wheelchair sports medicine involves the assessment of recreational and competitive sport capacities of physically disabled individuals, medical classification to allow fair competition among athletes with various types and degrees of disability, the prevention, diagnosis, and treatment of athletic injuries, and research into the biomechanics and physiology of wheelchair athletics. Involvement in wheelchair sports medicine activities increases professional awareness and provides a valuable referral source for organized sports activities.