Power seat function usage and wheelchair discomfort for power wheelchair users

Objectives: To investigate correlations between power seat functions (PSFs) usage and wheelchair discomfort.

Design: Quasi-experimental design: Time series design.

Setting: In-home trial in participants’ home/community.

Participants: Thirteen power wheelchair users who independently used power wheelchairs equipped with PSFs as their primary means of mobility.

Main Outcome Measures: PSF usage variables include the frequency of performing repositioning and using PSFs (tilt, recline, legrests and seat elevation), wheelchair occupancy, and driving distance. The Tool for Assessing Wheelchair disComfort (TAWC) were used to evaluate general discomfort and discomfort intensity.

Results: Spearman correlation coefficient showed that the frequency of using tilt, recline, and legrest is significantly correlated with discomfort intensity. Multiple regression analysis with backward stepwise indicated that these functions can explain 43.8% of the variance (R2?=?.438, F(3,33)?=?8.588, P?Conclusions: For people who used power wheelchairs equipped with PSFs, correlation analysis and regression modeling provided evidence from the quantitative data that increasing the frequency of using PSFs may decrease wheelchair discomfort. Future studies should include interventions to encourage people to use their PSFs appropriately.     

Upper Limb Pain in Anational Sample of Veterans With Paraplegia

Abstract

Background and Objectives: The purpose of this survey study was to examine the prevalence and intensity of pain and associated patient characteristics in a national sample of veterans with paraplegia. Of particular interest were upper limb (UL) pain conditions, which pose unique challenges to individuals who use a wheelchair for mobility. Because the risk for UL pain conditions appears to increase over time, the associations among age, duration of wheelchair use, and UL pain were evaluated.

Methods: A group of 1 ,6 7 5 individuals between the ages of 1 8 and 65 with a lesion between T2 and L2 and a mailing address on file were selected randomly from the Veteran's Affairs Spinal Cord Dysfunction Registry and mailed a survey packet. Of the deliverable packets, -46% were completed and returned.

Results: Approximately 81% of the respondents reported at least a minimal Ievei of ongoing unspecified pain and 69'7'o experienced current UL pain. Shoulder pain intensity was most severe du ring the performance of wheelchair-related mobility and transportation activities, suggesting that UL pain may have a significant impact on functional independence. Duration of wheelchair use modestly predicted shoulder pain prevalence and intensity, but age and the interaction between age and duration of wheelchair use did not.

Condusion: The data of the present study suggest that the development, persistence, and exacerbation of UL pain conditions in persans with paraplegia aremultidimensional processes. A comprehensive theoretic model is needed to integrate the existing empiric Iiterature in this area.     

Evaluation Of Selected Sidewalk Pavement Surfaces For Vibration Experienced By Users Of Manual AndPowered Wheelchairs

Abstract

Background: Obstades such as bumps, curb descents, and uneven driving surfaces cause vibrations that affect the wheelchair, and in turn, the wheelchair user. Chronic exposure can cause low-back pain, disk degeneration, and other harmful effects. Little research has been conducted to assess the vibrations experienced by wheelchair users.

Objective: The purpose of this study was to conduct an evaluation of the vibration exposure du ring electric-powered wheelchair driving and mechanical energy requirements for manual wheelchair propulsion over selected sidewalk surfaces. The goal was to determine the criteria for a wheelchair-pedestrian access route that does not require excessive propulsive work or expose wheelchair users to potentially harmful vibrations.

Methods: Ten unimpaired individuals participated in this study. Six sidewalk surfaces were tested. Measured variables included power of the acceleration per octave, mechanical work to propel over surfaces, peak acceleration, and frequency at which peak acceleration occurs.

Results: For both the manual and electric-powered wheelchair, at 1 m/s, significant differences were found in peak accelerations between the seat and footrest (P < 0.0001) and between the sidewalk surfaces (P = 0.004 ). The greatest risk for injury caused by shock and vibration exposure occurs at frequ encies near the natural frequency of seated humans (4-15 Hz). The values for work required to propel over the surfaces tested were not stat istically significantly different. Besides appearance and construction, the only distinguishing characteristic was surface roughness caused by the joints.

Conclusion: When treating the poured concrete sidewalk as the standard, surfaces 2, 3, 5, and 6 compared most favorably in t erms of vibration exposure, whereas surface 4 produced mixed results. Surfaces 2, 3, 5, and 6 yielded results that were similar to the poured concrete sidewalk and could be considered acceptable for wheelchair users. in conclusion, surfaces other than the t raditional poured concrete can be used for pedestrian access routes without adding vibration exposure or reducing propulsion efficiency.     

Evaluation of activity monitors in manual wheelchair users with paraplegia

Abstract

Objective: The aim of this study was to evaluate the performance of SenseWear^® (SW) and RT3 activity monitors (AMs) in estimating energy expenditure (EE) in manual wheelchair users (MWUs) with paraplegia for a variety of physical activities.

Methods: Twenty-four subjects completed four activities including resting, wheelchair propulsion, arm-ergometry exercise, and deskwork. The criterion EE was measured by a K4b2 portable metabolic cart. The EE estimated by the SW and RT3 were compared with the criterion EE by the absolute differences and absolute percentage errors. Intraclass correlations and the Bland and Altman plots were also used to assess the agreements between the two AMs and the metabolic cart. Correlations between the criterion EE and the estimated EE and sensors data from the AMs were evaluated.

Results: The EE estimation errors for the AMs varied from 24.4 to 125.8% for the SW and from 22.0 to 52.8% for the RT3. The intraclass correlation coefficients (ICCs) between the criterion EE and the EE estimated by the two AMs for each activity and all activities as a whole were considered poor with all the ICCs smaller than 0.75. Except for deskwork, the EE from the SW was more correlated to the criterion EE than the EE from the RT3.

Conclusion: The results indicate that neither of the AMs is an appropriate tool for quantifying physical activity in MWUs with paraplegia. However, the accuracy of EE estimation could be potentially improved by building new regression models based on wheelchair-related activities.     

Effect of motorized scooters on physical performance and mobility: a randomized clinical trial

OBJECTIVE: To investigate the effects of providing a motorized scooter on physical performance and mobility. DESIGN: Randomized clinical trial comparing scooter users with usual care. SETTING: One academic and 1 Veterans Affairs medical center. PARTICIPANTS: Ambulatory, community-dwelling outpatients with rheumatoid arthritis or osteoarthritis of the knee. INTERVENTION: Provision of a motorized scooter for 3 months. MAIN OUTCOME MEASURES: Six-minute walk distance (6MWD) and mobility methods in diverse locations at baseline, 1 month, and 3 months, and accidents while using the scooter. RESULTS: The majority of scooter subjects (n=16/22 [72.7%]) used the scooter 4 or more days per week. The difference+/-standard deviation between the 2 groups in change in 6MWD over the study period was not statistically significant (scooter users, 16.9+/-73.0 m [55.5+/-239.6 ft]; usual care, 17.2+/-72.5 m [56.5+/-238.0 ft], P=.55). Four (18.1%) scooter users reported 9 accidents. Over the study period, the proportion of persons reporting use of a scooter (provided by the study or otherwise available) increased in the scooter-users group (eg, food stores, 16.7% to 52.6%; doctor's office, 0% to 35.7%) but not the usual-care group (food stores, 9.1% to 9.5%; doctor's office, 0% to 0%). CONCLUSIONS: Motorized scooters provided to ambulatory persons with arthritis were used intermittently. The greatest short-term risk from scooter usage appeared to be minor collisions.     

Stroke pattern and handrim biomechanics for level and uphill wheelchair propulsion at self-selected speeds

OBJECTIVES: To investigate the natural stroke patterns of wheelchair users pushing on a level surface, to determine if users adapt their stroke patterns for pushing uphill, and to assess whether there are biomechanic advantages to one or more of the stroke patterns. DESIGN: Case series. SETTING: Biomechanics laboratory. PARTICIPANTS: Twenty-six manual wheelchair users with a spinal cord injury. INTERVENTION: Subjects pushed their own wheelchairs at self-selected speeds on a research treadmill set to level, 3 degrees , and 6 degrees grades. Stroke patterns were measured using a motion capture system. Handrim biomechanics were measured using an instrumented wheel. MAIN OUTCOME MEASURES: Stroke patterns were classified for both level and uphill propulsion according to 1 of 4 common classifications: arcing, semi-circular, single-looping (SLOP), and double-looping (DLOP). Biomechanic outcomes of speed, peak handrim force, cadence, and push angle were all compared across stroke classifications using an analysis of variance. RESULTS: Only 3 of the 4 stroke patterns were observed. None of the subjects used the semi-circular pattern. For level propulsion, the stroke patterns were fairly balanced between arcing (42%), SLOP (31%), and DLOP (27%). Subjects tended to change their stroke pattern for pushing uphill, with 73% of the subjects choosing the arcing pattern by the 6 degrees grade. No statistically significant differences were found in handrim biomechanics or subject characteristics across stroke pattern groups. CONCLUSIONS: Wheelchair users likely adapt their stroke pattern to accommodate their propulsion environment. Based on the large percentage of subjects who adopted the arcing pattern for pushing uphill, there may be benefits to the arcing pattern for pushing uphill. In light of this and other recent work, it is recommended that clinicians not instruct users to utilize a single stroke pattern in their everyday propulsion environments.     

Consequences of a cross slope on wheelchair handrim biomechanics

OBJECTIVE: To test the hypothesis that pushing on a cross slope leads to increased handrim loading compared with that found on a level surface. DESIGN: Case series. SETTING: Biomechanics laboratory. PARTICIPANTS: Twenty-six manual wheelchair users. INTERVENTION: Subjects pushed their own wheelchairs on a research treadmill set to level, 3 degrees , and 6 degrees cross slopes. Propulsion speed was self-selected for each cross-slope condition. Handrim biomechanics were measured for the downhill wheel, using an instrumented wheelchair wheel and a motion capture system. MAIN OUTCOME MEASURES: Speed, peak kinetics (force, rate of loading, torque), push angle, cadence, push distance, and power output were averaged over a 20-push set for each subject and each cross-slope condition. Outcomes were compared across cross slopes using a repeated-measures analysis of variance. RESULTS: Push angle and cadence were unaffected by cross slope. A trend of decreasing self-selected speeds with increasing cross slope was not significant. There were considerable increases in the peak kinetic measures, with the axial moment increasing by a factor of 1.8 on the 6 degrees cross slope (P=.000). More pushes were required to cover the same distance when on a cross slope (P<.034). The power required for propulsion increased by a factor of 2.3 on the 6 degrees cross slope (P=.000). CONCLUSIONS: Users must push harder when on a cross slope. This increased loading is borne by the users' arms, which are at risk for overuse injuries. Exposure to biomechanic loading can be reduced by avoiding cross slopes when possible.     

Investigating the Efficacy of Web-Based Transfer Training on Independent Wheelchair Transfers Through Randomized Controlled Trials

Objectives

To determine the efficacy of a web-based transfer training module at improving transfer technique across 3 groups: web-based training, in-person training (current standard of practice), and a waitlist control group (WLCG); and secondarily, to determine subject factors that can be used to predict improvements in transfer ability after training.

Pediatric Power Wheelchairs: Evaluation of Function in the Home and School Environments

The purpose of this study was to compare the performance of four power wheelchairs when used by children to perform a variety of indoor activities. Eight boys and eight girls performed a series of 11 functional tasks when positioned in each of four different power wheelchairs reflecting different design classes. There were no significant differences for many of the dependent variables. However, the Everaid Turbo was significantly better for functional positioning at a standard kitchen table and at school desks and for accessing objects at different heights. By contrast the Invacare Jaguar was better for straight-line driving speed. Other findings include children's subjective impressions of the four power wheelchairs.