Wheelchair Seating Research Articles

Wheelchair seating: A study on the healthy elderly

Background: Many frail elderly and disabled persons have to use a manual wheelchair to remain mobile and active. Apart from a well-fitted wheelchair, an appropriate wheelchair cushion is considered crucial for postural support and to prevent complications.Aim: To examined the effect of two types of seat cushions in two types of wheelchairs with regard to pelvic rotation, respiratory function, and interface pressure.Material and methods: Forty healthy elderly between 67 and 85 years of age participated. Two types of commonly used manual wheelchairs and two types of seat cushions were tested. Interface pressure, pelvic position, and respiratory function were measured using a sensor array mat, a study-specific inclinometer, and a spirometer.Results: Differences in interface pressure and pelvic rotation between cushions were found in both wheelchairs. Compared with sitting on a standard cushion, sitting on the positioning cushion increased peak pressure. The posterior pelvic tilt increased with the positioning cushion in the Etac Cross wheelchair and for both cushions in the Etac Cross wheelchair compared with the HD Balance wheelchair. No difference was observed in respiratory function.Conclusions: This study highlights the importance of a thorough evaluation of the effects of wheelchair interventions, especially for the elderly and disabled.

Design and evaluation of a seat orientation controller during uneven terrain driving

Electric powered wheelchairs (EPWs) are essential devices for people with disabilities as aids for mobility and quality of life improvement. However, the design of currently available common EPWs is still limited and makes it challenging for the users to drive in both indoor and outdoor environments such as uneven surfaces, steep hills, or cross slopes, making EPWs susceptible to loss of stability and at risk for falls. An alternative wheel-legged robotic wheelchair, “MEBot”, was designed to improve the safety and mobility of EPW users in both indoor and outdoor environments. MEBot is able to elevate its six wheels using pneumatic actuators, as well to detect changes in the seat angle using a gyroscope and accelerometer. This capability enables MEBot to provide sensing for a dynamic self-leveling seat application that can maintain the center of mass within the boundaries of the wheelchair, thereby, improving EPW safety. To verify the effectiveness of the application, MEBot was tested on a motion platform with six degrees of freedom to simulate different slopes that could be experienced by the EPW in outdoor environments. The results demonstrate the robustness of the application to maintain the wheelchair seat in a horizontal reference against changes in the ground angle.

A fuzzy logic controller to seat comfort correction for manually propelled wheelchair - a case study

Abstract: The subject of discussion is the construction of a fuzzy controller of the wheelchair seat correction in terms of improving the moving comfort parameter for people with physical disabilities. The Sugeno type fuzzy controller has been created for the seat comfort improvement of a wheelchair. The fuzzy controller is compared with PID and the results shows reasonable comfort improvement. The experiments have been performed in Matlab-Simulink.

Does a Novel-Developed Product of Wheelchair Incorporating Pelvic Support Prevent Forward Head Posture during Prolonged Sitting?

Disabled elderly individuals with kyphosis or loss of muscle strength often display forward head posture (FHP). This study aimed to determine the utility of a wheelchair incorporating pelvic support in preventing FHP in disabled elderly individuals. In this study, 14 disabled elderly individuals (87.1 ± 8.1 years) were selected. A wheelchair incorporating pelvic support (RX_ABS Lo) and a basic wheelchair (RX-1) were used. Each individual sat on both wheelchairs for 30 minutes. RX_ABS Lo has two belts to support the pelvic and thorax. Postures were recorded in the sagittal plane using a video camera. Cervical and trunk angles from horizontal were measured every 5 minutes. Simultaneously, contact areas and total pressures applied to the wheelchair seats and back supports were measured every 5 minutes. Comparisons of area under the curve values between the wheelchairs were performed using the paired t-test. Comparisons of time-dependent parameters for each wheelchair were performed using repeated one-way ANOVA. Cervical angles were greater when using RX_ABS Lo than RX-1. Although cervical angles were unchanged during 30 minutes when using RX_ABS Lo, the angles were significantly decreased after 30 minutes of using RX-1. Back support pressures and contact areas were greater for RX_ABS Lo than for RX-1. No significant difference in back support pressure distributions was observed during 30 minutes in the wheelchairs. The RX_ABS Lo may have utility in improving FHP by increasing cervical angles and improving stability with a back support to the upper thorax, lower thorax, and pelvis during prolonged sitting.

Car Transfer and Wheelchair Loading Techniques in Independent Drivers with Paraplegia.

Car transfers and wheelchair (WC) loading are crucial for independent community participation in persons with complete paraplegia from spinal cord injury, but are complex, physically demanding, and known to provoke shoulder pain. This study aimed to describe techniques and factors influencing car transfer and WC loading for individuals with paraplegia driving their own vehicles and using their personal WCs. Sedans were the most common vehicle driven (59%). Just over half (52%) of drivers place their right leg only into the vehicle prior to transfer. Overall, the leading hand was most frequently placed on the driver’s seat (66%) prior to transfer and the trailing hand was most often place on the WC seat (48%). Vehicle height influenced leading hand placement but not leg placement such that drivers of higher profile vehicles were more likely to place their hand on the driver’s seat than those who drove sedans. Body lift time was negatively correlated with level of injury and age and positively correlated with vehicle height and shoulder abduction strength. Drivers who transferred with their leading hand on the steering wheel had significantly higher levels of shoulder pain than those who placed their hand on the driver’s seat or overhead. The majority of participants used both hands (62%) to load their WC frame, and overall, most loaded their frame into the back (62%) vs. the front seat. Sedan drivers were more likely to load their frame into the front seat than drivers of higher profile vehicles (53 vs. 17%). Average time to load the WC frame (10.7 s) was 20% of the total WC loading time and was not related to shoulder strength, frame weight, or demographic characteristics. Those who loaded their WC frame into the back seat had significantly weaker right shoulder internal rotators. Understanding car transfers and WC loading in independent drivers is crucial to prevent shoulder pain and injury and preserve community participation.

최적의 전동휠체어 시트 평형유지를 위한 상호보안 필터 기반의 스마트 제어 시스템 연구

본 논문에서는 ATmega기반의 스마트 제어보드를 이용하여, 지형의 경사로에 따라 실시간으로 전동휠체어의 시트를 제어하는 시스템을 제안한다. 스마트 제어보드에는 자이로 및 가속도 센서와 Tilt센서가 포함되어 있으며, 전동휠체어가 다양한 경사로 지형을 지나갈 때 실시간으로 2개의 센서를 이용하여, 지형을 파악할 수 있도록 구성되었다. 본 논문에서는 정확한 지형을 파악할 수 있도록 자이로 센서와 가속도 센서 기반에 상호보안 필터를 적용하여, 전동휠체어가 이동 중에 출력되는 센서 값의 노이즈를 해결하였다. 이를 기반으로 전동휠체어가 이동시 센서 출력 값의 노이즈로 인하여, 시트가 지속적으로 흔들리지 않고 안정적으로 시트 평행을 유지하는 것을 확인할 수 있다. 본 논문에서는 사용자의 편의를 위해 전동휠체어에 익숙하지 않은 사람들이 쉽게 제어할 수 있도록 스마트 폰 기반의 제어 플랫폼을 제공한다. 스마트 폰의 제어플랫폼은 전동휠체어의 현재 상태를 실시간으로 모니터링 할 수 있으며, 욕창 방지와 관련하여, 시트의 기울기를 임의적으로 제어할 수 있도록 도와준다. In this paper, we propose a system for controlling the seat of the electric wheelchair depending on the slope of the terrain in real time by using the ATmega smart control based on the board. Smart control board includes a gyro sensor, an acceleration sensor and Tilt sensor, when the electric wheelchairs pass slope of the terrain, they use three sensors to identify terrain configuration in real time. We also applied the Complementary Filter in the gyro sensor and acceleration sensor, so the electric wheelchairs know the exact terrain by solving the interference during the movement. Based on this, the noise power wheelchair due to the movement will be reduced, the seat continues reliably movement without being vibration. In this paper, providing an application on the smart phone platform for the convenience of users who are not familiar with how to use electric wheelchairs, they can easily control wheelchairs. Control platform of the smart phone is able to monitor the electric wheelchair in real-time, with regard to pressure prevention, help the slope of the seat to be arbitrarily controlled.

Lifestyle risk factors for pressure ulcers in community-based patients with spinal cord injuries in Japan.

Case-control study. To identify daily living-related risk factors for pressure ulcer (PU) occurrence in community-living patients with spinal cord injury (SCI). To determine whether seat pressure influences PU occurrence, and how often patients with SCI perform pressure relief activities while living in the community. Kanagawa Rehabilitation Hospital, Kanagawa, Japan. Thirty-one patients admitted to this hospital for PU treatment were included in the case (PU) group. Thirty outpatients who did not have PUs at the time of the study, and had lived without PUs for at least a year, were included in the control (No PU) group. Patients were interviewed about lifestyle-related PU risk factors and a pressure-mapping system was used to measure interface pressure (IP) on their wheelchair seat. The No PU group patients recorded their daily activities and pressure relief maneuvers for 1 week. Eight lifestyle factors and one risk assessment scale significantly differed between groups. Three factors showed significant odds ratios by logistic regression. IP did not significantly differ between groups. The self-counted number of pressure relief maneuvers (median (25th-75th percentile)) performed per hour in the No PU group was 2.5 (0.7-4.3) and including transfer and urination was 3.5 (2.0-5.3). We identified potential PU risk factors related to lifestyle. The scores of one risk assessment scale were also associated with PU risk. Our results did not suggest an IP damage threshold. Patients in the No PU group performed pressure relief maneuvers, including related activities, approximately once every 17 min.

An Efficient Electronic Wheelchair Seat Balancing Maintain Methodology Applying Smart Sensors

In this paper we propose a new solution which utilizing the Gyro Sensor and Tilt Sensor in real-time controlling the balance of wheelchair seat. The existing wheelchair systems have the risk of falling when users go uphill because of the uneven weight allocation. But when applying our new method, the wheelchair seat can automatically adjust to maintain the balance therefore provides a safer and more stable ride. In order to adjust the seat correctly, we calculate the seat angle using Tilt Sensor. However, due to the law of inertia when wheelchair is moving there is deviation in output value of Tilt Sensor. To solve this problem, a Gyro sensor is used for measuring the acceleration and get the correct value of tilting angle. Through various experimentations we can prove that by taking advantage of Gyro sensor and Tilt sensor combination, the system is able to determine the correct seat angle in both cases when the wheelchair moving or not. We also tackle the power consumption issue in wheelchair, by using ZigBee sensor module to retrieve terrain information in advance and controlling the balance by two motors thus the overall power consumption for seat balancing is reduced significantly.

Prevalence of Sensor Saturation in Wheelchair Seat Interface Pressure Mapping

Pressure mapping is a frequently used tool with great power to provide information about the forces between a patient and a wheelchair seat. One widely recognized limitation to this paradigm is the possibility of data loss due to sensor saturation. In this study, we seek to quantify and describe the saturation observed in the measurement of interface pressures of wheelchair users. We recorded approximately two minutes of interface pressure data from 22 elderly wheelchair users (11M/11F, 80 ± 10 years) and found that 4.7% of data frames had 1 saturated sensor, and 9.0% had more than one saturated sensor, for a total of 13.7% of all frames of data. Data from three of the 22 subjects (13.6%) were substantially affected by the persistent presence of saturated sensors. We conclude that for this population of elderly wheelchair users, sensor saturation may be a concern and should be factored properly into study design a priori.

Comfort and stability of wheelchair backrests according to the TAWC (tool for assessing wheelchair discomfort)

Purpose: The goal of this study was thus to determine if people with different types of wheelchair backrests on their personal wheelchairs reported different levels of comfort as measured by the Tool for Assessing Wheelchair disComfort (TAWC). Methods: Participants were between 18 and 80 years of age and were manual wheelchair users. The TAWC was used to assess the participants’ wheelchair seating discomfort levels with the wheelchair and seating systems. Results: We surveyed 131 wheelchair users to assess the comfort of their backrests on their personal wheelchairs and found a trend suggesting that rigid backrests are were less comfortable as compared with sling backrests. This finding was statistically significant in a subgroup of participants with tetraplegia. Conclusions: Although many clinicians expect rigid backrests to be more comfortable because they may provide more support, the higher discomfort ratings among rigid backrest users with tetraplegia may be due to sub-optimal shape, fit, adjustment or user preferences.Implications for RehabilitationDevelopment of a measure for long-term seating discomfort is needed.Design and development of better rigid backrests that are functional but provide adequate comfort are in need.

Experiments and Evaluation of Body Pressure Distribution on Wheelchair Cushion

To study the relationship between wheelchair cushion shape and seat cushion comfort. By measuring sitting pressure distributions on wheelchair cushions with different shape, indices of sitting pressure such as the contact area, maximum sitting pressure were discussed along with method for subjective evaluation and objective test combination to analyze the relationship between seat cushion shape and seat cushion comfort. The experimental results from subjective assessment on three kinds of seat cushion indicate that the cushion shape is an important factor affecting seating comfort .The experimental results from objective assessment indicate that the contact area and maximum sitting pressure can preferably reflect the comfort of seat cushion and be used to evaluate the comfort of seat cushion.

A survey of protective cushion usage in individuals with spinal cord injury while traveling in a motor vehicle and on a commercial airliner

ObjectiveWhile there are specific recommendations for pressure relieving cushions when seated in a wheelchair, there is a paucity of information regarding prescribed wheelchair cushions for persons with spinal cord injury (SCI) when traveling and not in their wheelchair seat. A questionnaire was designed to ascertain if individuals with SCI who are primarily wheelchair users utilize a prescribed wheelchair cushion when traveling in a motor vehicle (MV) or on a commercial airliner, as not utilizing one may be a causative factor in developing pressure ulcers.Design and settingSurvey design in an outpatient SCI rehabilitation setting.ParticipantsFull-time wheelchair users, with chronic (>1 year) SCI.ResultsForty-two participants completed the survey, with a mean age of 39 years old and time post-injury of 10.4 years. All subjects used a prescribed wheelchair cushion when seated in their wheelchair. Twenty-seven subjects reported transferring to a MV seat (59.5% of sample), with 25 (92.6%) reporting not using a prescribed wheelchair cushion when sitting directly on the MV seat. For subjects who traveled on an airplane (n = 23–54.8%), 19 (82.6%) reported that they do not sit on a prescribed specialty cushion.ConclusionPersons with chronic SCI, who are primary wheelchair users, utilize prescribed wheelchair cushions when sitting in their wheelchair, but most do not utilize a prescribed wheelchair cushion when seated in a MV (if they transfer out of their chair) or on a airplane seat. Studies to determine the pressures over the bony prominences on their travel surfaces may need to be undertaken to see whether the pressures are appropriate, as they may be a source of skin breakdown.

Pilot study of strap-based custom wheelchair seating system in persons with spinal cord injury.

Custom wheelchair seats can be used to help prevent pressure ulcers in individuals with spinal cord injury. In this study, a strap-based system was evaluated in three Veterans with spinal cord injury. Interface pressure distributions were measured after transfers, wheeling, and pressure relief maneuvers and after fittings by three different therapists. We found that pressure distribution measures were not generally affected after transfers and wheeling using the strap-based wheelchair and that pressure relief maneuvers were able to be performed. Additionally, all therapists were able to customize the wheelchair seat to clinically acceptable levels in 4 to 40 min for the three subjects. Future studies can test the long-term effects of using the strap-based wheelchair seat and identifying individuals that would most benefit from a rapidly customizable wheelchair seat.

512 ステレオカメラを用いたマーカー自動検出による車いす座位姿勢計測(OS5-(3),OS5 オーガナイズドセッション《ライフサポートにおける工学技術》)

512 ステレオカメラを用いたマーカー自動検出による車いす座位姿勢計測(OS5-(3),OS5 オーガナイズドセッション《ライフサポートにおける工学技術》)

Effect of interpolation on parameters extracted from seating interface pressure arrays.

Interpolation is a common data processing step in the study of interface pressure data collected at the wheelchair seating interface. However, there has been no focused study on the effect of interpolation on features extracted from these pressure maps, nor on whether these parameters are sensitive to the manner in which the interpolation is implemented. Here, two different interpolation paradigms, bilinear versus bicubic spline, are tested for their influence on parameters extracted from pressure array data and compared against a conventional low-pass filtering operation. Additionally, analysis of the effect of tandem filtering and interpolation, as well as the interpolation degree (interpolating to 2, 4, and 8 times sampling density), was undertaken. The following recommendations are made regarding approaches that minimized distortion of features extracted from the pressure maps: (1) filter prior to interpolate (strong effect); (2) use of cubic interpolation versus linear (slight effect); and (3) nominal difference between interpolation orders of 2, 4, and 8 times (negligible effect). We invite other investigators to perform similar benchmark analyses on their own data in the interest of establishing a community consensus of best practices in pressure array data processing.

The influence of wheelchair cushions and deflection of the wheelchair seat on sitting motion

The influence of wheelchair cushions and deflection of the wheelchair seat on sitting motion

Research on Body Pressure Distribution at Different Angles of Wheelchair Seat Surface

The objective of the present study was to study the effect of seat angle change on body pressure distribution. The body pressure distribution and body subjective comfort evaluation were recorded in five angles of wheelchair seat surface(0 °, 3 °, 6 °, 9 °and 12 °) by using X-Sensor system. 20 healthy volunteers (10 males and 10 females) were tested to obtain the average pressure of back, the maximum pressure of back, the contact area of back, the average pressure of buttock, the maximum pressure of buttock, the contact area of buttock. The experimental data were analyzed by statistical analysis software SPSS 19.0 and MATLAB. Finally the comfort indicator of wheelchair was determined based on body pressure distribution, and the more comfortable angle of wheelchair seat surface was also obtained, which was 3.17°. The study should provide a strong help for the comfortable wheelchair designing.

“I Want to Tea”: An Entering Medical Student's Perspective on Geriatrics

Every Friday, I eat meals in the dining room of an assisted living facility, alongside fuzzy-haired seniors and caregivers spooning tinned peaches into their mouths. This has been my life for the past 3 years. Winnie isn't doing well, the lines of her face tightening every time she opens her mouth. Today, she's convinced the nursing aides have stolen her jewelry. Angrily clasping at her chest, each time exposing a small square of wrinkled skin, she shouts: “Where are my pearls?” I glance at the glistening beads threaded around her neck. I don't know what to say. A phrase flashes into my mind: Alzheimer's World. Coined by Bob Demarco from the Alzheimer's Reading Room, Alzheimer's World is the absurdist universe that people with dementia inhabit. It's a planet populated with alternative conventions, with figures coming back from the dead and words sliding into a perpetual jumble. Although to some extent, this universe resembles our own reality, it's a reality that's been picked up like a vase of flowers and repositioned slightly to the left. The important thing about Alzheimer's World is not that you bring its residents back to the real world (for such a thing is impossible); it's that you stay with them inside their convoluted universe. So I play along, helping Winnie open the drawers in search of the missing pearls. “I want to tea,” Winnie says, forlornly. I know what she means. I wheel her into the bathroom and let her go about her business. There's a lot I've learned from spending time with elderly people: Use “we” instead of “you.” Follow up on your promises. Enunciate. Use your eyebrows. I've also gotten to understand the language of dementia. Sometimes, when a person says “no,” it doesn't really mean “no.” Like a young child learning to talk, but sadly in a developmental reverse, it's just the only word she has left. Most believe a doctor's role is primarily to save lives. If an individual is sick, you prescribe a pill. If he has a tumor, you put him on the operating table. But what's the cure for old age? How do you rescue someone who's already pushed the brakes on life? Past a certain age, no one can stop the inevitable deterioration of the human body. Arteries harden, arthritic knots work their way into hands, feet, and backs. Synapses fizzle out. What I've realized is that caring for those afflicted with “old age” is not to cure them of their diseases but to allow them, as best we can, to live a life of dignity and grace until the end. To look out for the little, less-romantic things. Whether the individual is at risk for falling. Whether her clothes are going to chafe in her wheelchair seat. What I like about medicine, that imperfect art, is how nothing is ever straightforward. Truths are challenged every day, with one medication blasting through viruses one day, burning holes through the person's digestive system the next. It becomes imperative to adjust to changes quickly and judiciously, to draw from a large and kaleidoscopically changing body of knowledge beneath the surface level formula of diagnose, treat, cure. I've found myself gravitating toward geriatrics because such readjustments are integral to the practice. Because each body deteriorates in a different way, each regimen of care must also be individualized. Volunteering at the hospice, I'm seldom told what “disease” my patient has. We're taught to get to know the people underneath, rather than let an illness define them. “I want to go home,” Winnie says as she exits the bathroom. I step in and flush the toilet. Conflict of Interest: The editor in chief has reviewed the conflict of interest checklist provided by the author and has determined that the author has no financial or any other kind of personal conflicts with this paper. Author Contributions: Jennifer Xu is the sole contributor of this article. Sponsor's Role: None.

Nanosilver: Weighing the Risks and Benefits

It takes a special sort of case to spur attorneys into a debate over the drooling habits of toddlers. Yet that’s where lawyers from the Natural Resources Defense Council (NRDC), the U.S. Environmental Protection Agency (EPA), and Swiss chemicals company HeiQ found themselves in January 2013 as they debated in a federal appeals court the extent to which 1-year-olds and 3-year-olds chew, salivate, and swallow.1 At issue in the NRDC’s suit against the EPA, which is still awaiting ruling, was whether the agency was right in granting a conditional registration in December 2011 to a nanosilver-based antimicrobial fabric treatment manufactured by HeiQ.2 The EPA’s risk assessment was based in part on assumptions about exposure of 3-year-olds by sucking or chewing on nanosilver-laced textiles such as clothing, blankets, and pillowcases. Silver nanoparticles are added to a variety of textiles and home goods as an antimicrobial. Although silver has been used safely for centuries, some question whether the rapid expansion of new exposure sources to nanosilver could have adverse consequences. ... NRDC lawyer Catherine Rahm, however, begged to differ with the agency’s methods. In the January hearing, she argued that the agency record shows infants are more likely than any other subset of children to chew on fabrics that could contain the pesticide, and that if the agency were to recalculate its risk assessment based on the body weight of a 1-year-old, nanosilver concentrations in HeiQ’s product could result in potentially harmful exposures. It’s an obscure but critical distinction as far as risk assessment goes. And given the implications for HeiQ and other companies looking to follow in its footsteps, the case has landed at the center of a prolonged conflict over the regulation of nanosilver and the growing deployment of this antimicrobial ingredient in a variety of commercial and consumer products. Yet regardless of which side prevails in the case, the truth about nanosilver is not black and white. Even the loudest voices joining the NRDC’s call for strict regulation of nanosilver concede that context is key. “I’m not somebody who is for or against nano,” says Ian Illuminato, who directs Friends of the Earth’s U.S. nanotechnology campaign, which has produced a series of reports on the potential dangers of nanosilver and other nanomaterials. “I’m just saying we need to do this in a mature and adult way. That’s not to say this isn’t a helpful technology and it doesn’t have a place in our future, but in the way it’s evolving right now, it’s very risky.” Greg Lowry, a researcher at Carnegie Mellon University who studies the fate of nanoparticles in the environment, agrees that the use of nanosilver is a matter of balancing risk and reward. “There’s a tremendous potential benefit to the use in some of these products,” he says. “What one has to do is to ask yourself whether the benefits outweigh the risk.”

Patient and equipment profile for wheelchair seating clinic provision

Purpose: To characterise the provision of wheelchair seating both pre- and post-clinical intervention and compare and contrast the two largest diagnostic groups. Method: The case notes of those attending a wheelchair seating clinic for adults over a defined period were reviewed retrospectively. A classification system was devised that delineates between the complexity and type of equipment to gain a better understanding of provision. Results: 146 patients were included; mean age 45 years (SD 16); 53.4% male. The two most prevalent primary medical diagnoses were cerebral palsy (CP) and multiple sclerosis (MS); 48.6% and 20.5%, respectively. The MS group, in comparison to the CP group, were significantly more likely to be older, new to seating provision, have been seen more recently, have a powered wheelchair, self-propel their manual wheelchair, have low rather than high complexity equipment and have their equipment changed following assessment. Conclusions: The equipment classification system will allow results from different studies to be readily compared. The results for those with CP and MS reflect the respective stable and progressive nature of these conditions. Referrals for those with MS should be prioritised. Wheelchair seating users with MS should be reassessed ∼18 months after provision.Implications for RehabilitationA detailed classification of wheelchair seating equipment based on a recognised standard vocabulary, such as the one proposed, is required to gain a better understanding of provision.Wheelchair seating equipment budget and staffing levels should reflect the diagnostic make up of a service's patient population.Referrals for people with MS should be prioritised as their current wheelchair seating provision is more likely not to be meeting their needs.People with MS should have a clinical review 18 months after wheelchair seating provision.