Using high-resolution imaging to study the impact of the Kalogon wheelchair cushion on blood flow in the gluteal area.

AIM OF THE STUDY: This study investigated how the air-bladder offloading mode of the Orbiter by Kalogon wheelchair cushion (Orbiter) affected blood flow in the gluteal region of non-disabled subjects. The hypothesis was that the cushion's offloading mode would improve blood flow, resulting in reduced reactive hyperemia when compared to the static setting, or Loaded Control (LC). Furthermore, the study proposed a technique using a high-resolution image laser speckle contrast system to measure blood flow in the gluteal area. METHODS: Two procedures were carried out, one with the participant sitting on a cushion in LC, and the second, the cushion was set to offloading mode. Blood flow was measured through data imaging after each procedure. Three trials were performed, starting and ending in different cushion bladders. Customized algorithms were used to select regions of interest on the images for calculations. The Wilcoxon Signed-Rank Test was conducted to compare the offloads and loaded control values of each region of interest. Results were considered significant at α = 0.05. RESULTS: Ten healthy, non-disabled adults participated in the study, seven females and three males. There were no significant differences among the participants. However, results showed that seven subjects tended to decrease reactive hyperemia in the offload sequence of trial when the last two bladders offloaded were the sacrum followed by the right ischial tuberosity. CONCLUSIONS: The high-resolution imager showed that the Orbiter Offloads helped reduce reactive hyperemia in seven subjects, potentially improving blood flow. More research is necessary to comprehend the mechanisms of these effects fully.

Evaluation of interface pressure and temperature management in five wheelchair seat cushions and their effects on user satisfaction.

BACKGROUND: Factors such as the manufacturing materials, shape or even the mechanical and thermal response of sitting Pressure Redistribution Support Surfaces (PRSS) can be potential contributors to pressure ulcers. However, few studies have compared a number of characteristics of the most frequently used devices. OBJECTIVE: To compare three potential contributors to pressure ulcers in five commercial PRSS: pressure redistribution, temperature and perceived comfort. METHOD: Study with a cross-over randomized design in healthy volunteer participants. Data was collected in a temperature and relative humidity controlled environment. To assess thermal response, the temperature (Flir-E60) of the region of interest was captured before and after use of each PRSS for further analysis. The region of interest was the gluteal zone. To assess the pressure redistribution a pressure mat (XSensor®) was used between the 5 cushion and each study participant using a standardized method. Finally, a subjective perception questionnaire recorded comfort, adaptability and thermal sensation parameters. Data analysis levels of significance were set at 0.05. RESULTS: A total of 22 participants completed the assessments. There were no statistically significant differences in baseline temperatures between PRSS (>0.05). Pressure redistribution analysis showed significant differences between all PRSS in all variables evaluated except in the maximum and peak pressure index al sacrum. The subjective assessment suggested no major user-perceived differences between PRSS. CONCLUSION: Seat cushions made of open cell polyurethane foam blocks of variable hardness and the horseshoe cushion (also open cell polyurethane foam) seem to provide a more effective pressure relief characteristic than those injected with polyurethane foam and gel in most of the studied pressure variables. However, the cushions provide similar thermal response and perceived comfort.

Comparison of different wheelchair seating on thermoregulation and perceptual responses in thermoneutral and hot conditions in children.

We examined the effects of 4 different wheelchair seatings on physiological and perceptual measures in 21 healthy, pre-pubertal children (9 ±â€¯2 years). Participants were able-bodied and did not regularly use a wheelchair. Participants sat for 2 h in Neutral (∼22.5 °C, ∼40%RH) and Hot (∼35 °C, ∼37%RH) conditions. Four seating technologies were: standard incontinent cover and cushion (SEAT1); standard incontinent cover with new cushion (SEAT2) were tested in Neutral and Hot; new non-incontinent cover with new cushion (SEAT3); new incontinent cover and new cushion (SEAT4) were tested in Neutral only. Measurements included skin blood flow (SkBF), sweating rate (SR) and leg skin temperature (TlegB) on the bottom of the leg (i.e. skin-seat interface), heart rate (HR), mean skin temperature, tympanic temperature, thermal comfort, and thermal sensation. During Neutral, SkBF and TlegB were lower (∼50% and ∼1 °C, respectively) and SR higher (∼0.5 mg cm-2·min-1) (p < 0.05) with SEAT3 compared to all other seats. SkBF was ∼30% lower (p < 0.05) for SEAT2 and SEAT4 compared to SEAT1. No other differences were observed between SEATs (all p > 0.05). During Hot, HR and temperatures were higher than in Neutral but there were no differences (p > 0.05) between SEATs. New cover and cushion improved thermoregulatory responses during Neutral but not Hot. An impermeable incontinent cover negated improvements from cushion design. Seat cover appears more important than seat cushion during typical room conditions.

Mobility Device Quality Affects Participation Outcomes for People With Disabilities: A Structural Equation Modeling Analysis.

OBJECTIVE: To test the effect that indicators of mobility device quality have on participation outcomes in community-dwelling adults with spinal cord injury, traumatic brain injury, and stroke by using structural equation modeling. DESIGN: Survey, cross-sectional study, and model testing. SETTING: Clinical research space at 2 academic medical centers and 1 free-standing rehabilitation hospital. PARTICIPANTS: Community-dwelling adults (N=250; mean age, 48±14.3y) with spinal cord injury, traumatic brain injury, and stroke. INTERVENTIONS: Not applicable. MAIN OUTCOMES MEASURES: The Mobility Device Impact Scale, Patient-Reported Outcomes Measurement Information System Social Function (version 2.0) scale, including Ability to Participate in Social Roles and Activities and Satisfaction with Social Roles and Activities, and the 2 Community Participation Indicators' enfranchisement scales. Details about device quality (reparability, reliability, ease of maintenance) and device type were also collected. RESULTS: Respondents used ambulation aids (30%), manual (34%), and power wheelchairs (30%). Indicators of device quality had a moderating effect on participation outcomes, with 3 device quality variables (repairability, ease of maintenance, device reliability) accounting for 20% of the variance in participation. Wheelchair users reported lower participation enfranchisement than did ambulation aid users. CONCLUSIONS: Mobility device quality plays an important role in participation outcomes. It is critical that people have access to mobility devices and that these devices be reliable.

Ultrasonic Tethering to Enable Side-by-Side Following for Powered Wheelchairs.

In social situations, people who use a powered wheelchair must divide their attention between navigating the chair and conversing with people. These conversations could lead to increased mental stress when navigating and distraction from maneuvering the chair. As a solution that maintains a good conversation distance between the wheelchair and the accompanying person (Social Following), a wheelchair control system was developed to provide automated side-by-side following by wirelessly connecting the wheelchair to the person. Two ultrasonic range sensors and three piezoelectric ultrasonic transducers were used to identify the accompanying person and determine their position and heading. Identification involved an ultrasonic beacon worn on the person's side, at hip level, and receivers on the wheelchair. A drive control algorithm maintained a constant conversation distance along the person's trajectory. A plug-and-play prototype was developed and connected to a Permobil F5 Corpus wheelchair with a modified Eightfold Technologies SmartChair Remote. Results demonstrated that the system can navigate a wheelchair based on the accompanying person's trajectory, which is advantageous for users who require hands-free wheelchair control during social activities.

The impact of hoist sling fabrics on interface pressure whilst sitting in healthy volunteers and wheelchair users: A comparative study.

AIM OF THE STUDY: To evaluate the effect of three sling fabrics on gluteal interface pressure whilst sitting in a population of wheelchair users and to compare these to data previously collected in a pilot study with a healthy population. MATERIALS AND METHODS: A repeated measures experimental design was used with 32 adult wheelchair users (15 women, 17 men). Healthy population pilot study consisted of 61 participants (51 women, 10 men) recruited from staff and students at The University of Salford. METHODS: Gluteal pressures at six pressure zones were recorded using the X-sensor PX100 pressure sensor at 30 s intervals for 10 min. Data were collected in 4 conditions with participants seated in a standardised chair, followed by the chair with slings made of three different fabrics. RESULTS: The spacer fabric reduced the mean gluteal pressure more effectively than slipfit and polyester (p = 0.014 and p = 0.01 respectively, 95%CI) and reduced peak pressure at the left ischial tuberosity and coccyx when compared to the slipfit (p = 0.003 and p = 0.005) with the wheelchair users. When comparing data with the pilot study, the mean gluteal pressure and peak pressures at the ischial tuberosities and coccyx were significantly higher in the wheelchair user group (p < 0.005). CONCLUSION: The fabric identified as the most effective in reducing mean and peak pressures in both groups was the spacer fabric, suggesting that a spacer fabric sling is more likely to reduce the risk of pressure ulcer development. This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Microclimate evaluation of strap-based wheelchair seating systems for persons with spinal cord injury: A pilot study.

STUDY PURPOSE: The purpose of this pilot study was to assess microclimate characteristics of two versions of a strap-based wheelchair seating system (perforated and solid straps) and to conduct preliminary microclimate comparisons of subjects' current wheelchair seating systems. MATERIALS AND METHODS: In this pilot study, the microclimate properties of two variations (solid and perforated) of a strap-based seating system were compared with two commonly used seating systems. Six subjects sat on three different seating systems each for 100-min test periods, while temperature and relative humidity were measured with a single sensor adjacent to the skin-seat interface. Additionally, thermal images of the seat interface were collected before and after each test period. RESULTS: The thermal images revealed that the maximum surface temperature of the solid-strap-based seating system was significantly lower than the other seating systems, -1.21 °C. (95% CI -2.11 to -0.30, p = 0.02), immediately following transfer out of the seat. Five minutes after transferring out of the seat, the perforated-strap seat was significantly cooler than the other seats -0.94 °C. (95% CI -1.59 to -0.30), p = 0.01, as was the solid-strap-based seat, -1.66 °C. (95% CI -2.69 to -0.63), p = 0.01. There were no significant differences in interface temperature or relative humidity measured with the single sensor near the skin-seat interface. CONCLUSION: This pilot study offers preliminary evidence regarding the microclimate of the strap-based seating systems compared with other common seating systems. Clinically, the strap-based seating system may offer another option for those who struggle with microclimate management.

Preliminary development of an advanced modular pressure relief cushion: Testing and user evaluation.

STUDY AIM: Effective pressure relief cushions are identified as a core assistive technology need by the World Health Organization Global Cooperation on Assistive Technology. High quality affordable wheelchair cushions could provide effective pressure relief for many individuals with limited access to advanced assistive technology. MATERIALS: Value driven engineering (VdE) principles were employed to develop a prototype modular cushion. Low cost dynamically responsive gel balls were arranged in a close packed array and seated in bilayer foam for containment and support. Two modular cushions, one with high compliance balls and one with moderate compliance balls were compared with High Profile and Low Profile Roho® and Jay® Medical 2 cushions. METHODS: ISO 16480-2 biomechanical standardized tests were applied to assess cushion performance. A preliminary materials cost analysis was carried out. A prototype modular cushion was evaluated by 12 participants who reported satisfaction using a questionnaire based on the Quebec User Evaluation of Satisfaction with Assistive Technology (QUEST 2.0) instrument. RESULTS: Overall the modular cushions performed better than, or on par with, the most widely prescribed commercially available cushions under ISO 16480-2 testing. Users rated the modular cushion highly for overall appearance, size and dimensions, comfort, safety, stability, ease of adjustment and general ease of use. Cost-analysis indicated that every modular cushion component a could be replaced several times and still maintain cost-efficacy over the complete cushion lifecycle. CONCLUSION: A VdE modular cushion has the potential provide effective pressure relief for many users at a low lifetime cost.

Measuring the impact of cushion design on buttocks tissue deformation: An MRI approach.

AIM: To establish a research approach for describing how different wheelchair cushion designs impact buttocks tissue deformation during sitting. MATERIALS AND METHODS: The buttocks of 4 individuals with spinal cord injury and significant atrophy were scanned sitting in a FONAR Upright MRI. Scans were collected with the individuals' buttocks fully suspended without pelvic support, and seated on 3 different commercially available wheelchair cushions. Multi-planar scans were analyzed to provide 3D renderings and measurements of tissue thickness and shape. RESULTS: Bulk tissue thicknesses at the ischium, which rarely included muscle, were reduced by more than 60% on enveloping cushion designs studied (i.e., Roho HP and Matrx Vi), and more variably (23-60%) on an orthotic off-loading design (i.e., Java). Adipose was typically displaced posterior and superior from the unloaded condition, with more lateral displacement on the Roho HP and Matrx Vi and more medial displacement present on the Java. Large changes in angle at the sacro-coccygeal joint indicated significant loading on the region. Deformation at the greater trochanter was more consistent across surfaces. Greater interface pressures tended to be associated with greater deformation, but the relationship varied by individuals and was highly non-linear. CONCLUSIONS: The buttocks in this study all deformed significantly, but at different locations and in different manners across all 3 surfaces. Attention needs to be paid to the regions of greatest deformation. A future metric of shape compliance should consider cushion performance at all high risk regions, and changes to the amount and shape of tissue in the regions of interest.

Quality and Equity in Wheelchairs Used by Veterans.

OBJECTIVES: To assess in Veterans with spinal cord injury (SCI) or amputated limb (AL) the following: (1) patient demographics, medical factors, cultural and psychosocial characteristic by race; (2) wheelchair quality by race; and (3) the independent associations of patient race and the other factors with wheelchair quality. DESIGN: Cross-sectional cohort study. SETTING: Three Department of Veterans Affairs (VA) medical centers affiliated with academic medical centers. PARTICIPANTS: Eligible participants were Veterans with SCI or ALs (N=516); 482 of them completed the interview. Analyses were restricted to white and African American participants. Because there was no variation in wheelchair quality among AL patients (n=42), they were excluded from all but descriptive analyses, leading to a final sample size of 421. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURE: Wheelchair quality as defined by the Medicare Healthcare Common Procedure Coding System. RESULTS: We found race differences in many of our variables, but not in quality for manual (odds ratio [OR]=.67; 95% confidence interval [CI], .33-1.36) or power (OR=.82; 95% CI, .51-1.34) wheelchairs. Several factors including age (OR=.96; 95% CI, .93-.99) and income (OR=3.78; 95% CI, 1.43-9.97) were associated with wheelchair quality. There were no significant associations of cultural or psychosocial factors with wheelchair quality. CONCLUSIONS: Although there were no racial differences in wheelchair quality, we found a significant association of older age and lower income with poorer wheelchair quality among Veterans. Efforts are needed to raise awareness of such disparities among VA wheelchair providers and to take steps to eliminate these disparities in prescription practice across VA sites.

Rehabilitation Engineering & Assistive Technology Society (RESNA) position on the application of wheelchair standing devices: 2013 current state of the literature.

This article, approved by the Rehabilitation Engineering & Assistive Technology Society of North America Board of Directors on December 23, 2013, shares typical clinical applications and provides evidence from the literature supporting the use of wheelchair standers.

The child and family experience of power mobility: a qualitative synthesis.

AIM: The aim of this study was to critically synthesize qualitative evidence regarding the child and family experience of power mobility, and to examine how this evidence fits with current theoretical concepts. METHOD: Electronic database/hand searches were undertaken in September 2012 and updated in February 2014. The searches were restricted to qualitative studies published in English before February 2014 that included at least one child under the age of 19 with a disability and described an outcome related to the use of power mobility. Inclusion criteria were set a priori. Two reviewers independently screened titles, abstracts, and full-text articles and extracted data. McMaster qualitative review forms were used for quality appraisal. RESULTS: Of 259 titles, 21 met inclusion criteria. From 143 codes, 15 second-order themes were developed using constant comparison and analysis. Three overarching themes emerged: power mobility experience promotes developmental change and independent mobility; power mobility enhances social relationships and engagement in meaningful life experiences; and power mobility access and use is influenced by factors in the physical, social, and attitudinal environment. INTERPRETATION: This qualitative research provides rich and rigorous evidence supporting the benefits of power mobility for children and families. Numerous factors, which warrant careful consideration, influence power mobility access and use.

Relationships between wheeling parameters and wheelchair skills in adults and children with SCI.

STUDY DESIGN: Cross-sectional. OBJECTIVES: To determine the relationships between (1) wheeling parameters using the SmartWheel Clinical Protocol (SCP) and wheelchair skills (wheelchair skills test 4.1 (WST)) and (2) push effectiveness (m per push) and the WST, among individuals with spinal cord injury. SETTING: Biomechanics Laboratory, Canada. METHODS: Sixteen adults and eight children participated in this study. Multiple regression analyses were used to determine significant SCP predictors (that is, weight-normalised peak force, speed, push frequency and mechanical effectiveness) of WST score. To determine relationships between push effectiveness and WST scores, Pearson's correlations were calculated. RESULTS: SCP-TILE: speed and mechanical effectiveness explained 36% of the variance in the WST score. SCP-RAMP and SCP-CARPET: speed explained 58% and 37% of the variance in the WST score, respectively. Push effectiveness was significantly correlated with the WST score on all three surfaces (tile, ramp and carpet). CONCLUSION: Wheeling speed was a significant predictor of the WST score for all surfaces tested. Regression analyses demonstrated that SCP-RAMP had the strongest relationship with WST score. Therefore, when time is restricted, the SCP-RAMP may be the most predictive test and speed may be the most useful variable to evaluate. However, the authors do not believe that one single variable should ever replace a full assessment of skills.

Factors Associated With the Use of Standardized Power Mobility Skills Assessments Among Assistive Technology Practitioners.

This study investigated self-reported prevalence of and factors affecting clinicians' use of standardized assessments when evaluating clients for power mobility devices (PMDs), and explored assessments clinicians typically use when carrying out PMD evaluation. An e-mail survey was sent to assistive technology professionals listed in the Rehabilitation Engineering and Assistive Technology Society of North America directory. Three hundred fifty-four respondents, qualified to conduct formal power mobility skills assessments, completed the online survey. Of those, 122 (34.5%) respondents reported that they were aware of the presence of standardized performance-based power mobility skills assessments, but only 28 (7.9%) used these assessments in their practice. Multivariate analysis revealed that the odds of the respondents who use the standardized assessments were 18 times higher for those who were aware of the presence of these assessments than those who were not (adjusted odds ratio [OR] OR = 17.85, P < 0.0001). The odds of using the standardized assessment for respondents who did not identify themselves as occupational or physical therapists were five times higher than those who were therapists (adjusted OR = 0.20, P < 0.0001). This survey revealed that the assistive technology practitioners who recommend PMDs mainly use non-standardized mobility skills assessments.

Validity of a wheelchair perceived exertion scale (wheel scale) for arm ergometry exercise in people with spina bifida.

This study assessed the concurrent and construct validity of the Borg 6-20 Scale and WHEEL Scale during arm ergometry exercise stress testing in (n = 24) adolescents and adults with spina bifida. Significant, moderate, positive correlations were observed between power output and relative heart rate and power output to relative VO2peak. Further, a moderate, significant correlation between physiologic criterion variables and the rating of perceived exertion derived from the Borg Scale and the WHEEL Scale was found. Concurrent validity was supported by the following findings: (1) relative heart rate was significantly correlated with the Borg (Kendall's τ = .41) and WHEEL Scales (τ = .44), and relative VO2 was significantly correlated with the Borg (τ = .46) and WHEEL Scales (τ = .47); (2) content validity was supported by the finding that the Borg and WHEEL Scales shared significant variance (τ = .70), demonstrating internal consistency. The WHEEL Scale shows strong potential for use in this cohort subsequent to further testing and validation.

Measure it: proper wheelchair fit is key to ensuring function while protecting skin integrity.

The objectives of this article are to help the clinician to better recognize the basic biomechanics of posture, describe the appropriate means to configure a wheelchair to permit proper postural support, and to identify common problems arising from improper wheelchair fit.

From "wheelchair circuit" to "wheelchair assessment instrument for people with multiple sclerosis": reliability and validity analysis of a test to assess driving skills in manual wheelchair users with multiple sclerosis.

OBJECTIVES: To assess the reliability and validity of the Wheelchair Assessment Instrument for people with Multiple Sclerosis (WAIMS), a test to measure driving skills in manual wheelchair users with multiple sclerosis (MS). DESIGN: Three test trials per subject were conducted by 2 raters to examine reliability (inter- and intrarater) and validity (concurrent and construct). SETTING: A national multiple sclerosis rehabilitation center. PARTICIPANTS: Convenience sample of manual wheelchair users with MS (n=50), participating in an inpatient or outpatient rehabilitation program in a national multiple sclerosis center. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: The WAIMS consists of 8 items and results in 3 final test scores: ability sum score, performance time sum score, and covered distance. These 3 scores are used to calculate inter- and intrarater reliability, concurrent validity, and construct validity. Concerning validity, the test scores on the WAIMS are compared with (1) the Belgian medical prescription of a wheelchair on the item d445 (hand and arm use), based on the International Classification of Functioning, Disability and Health, (2) the Expanded Disability Status Scale, and (3) the mobility (wheelchair) item of the FIM. RESULTS: Intrarater reliability was found to be higher than interrater reliability. Except for the interrater reliability of the ability sum score, all intraclass correlation coefficients met our standard of 0.80. Concurrent validity was rather low, but construct validity showed that the WAIMS is a valid instrument to assess driving skills in manual wheelchair users with MS. CONCLUSIONS: The WAIMS is a promising tool to assess driving skills in manual wheelchair users with MS, but it needs some refinements and future studies to confirm this statement.

Evaluation of muscle fatigue of wheelchair basketball players with spinal cord injury using recurrence quantification analysis of surface EMG.

Wheelchair basketball is the most popular exercise activity among individuals with spinal cord injury (SCI). The purpose of this study was to investigate muscular endurance and fatigue in wheelchair basketball athletes with SCI using surface electromyography (SEMG) and maximal torque values. SEMG characteristics of 10 wheelchair basketball players (WBP) were compared to 13 able-bodied basketball players and 12 sedentary able-bodied subjects. Participants performed sustained isometric elbow flexion at 50% maximal voluntary contraction until exhaustion. Elbow flexion torque and SEMG signals were recorded from three elbow flexor muscles: biceps brachii longus, biceps brachii brevis and brachioradialis. SEMG signals were clustered into 0.5-s epochs with 50% overlap. Root mean square (RMS) and median frequency (MDF) of SEMG signals were calculated for each muscle and epoch as traditional fatigue monitoring. Recurrence quantification analysis was used to extract the percentage of determinism (%DET) of SEMG signals. The slope of the %DET for basketball players and WBP showed slower increase with time than the sedentary able-bodied control group for three different elbow flexor muscles, while no difference was observed for the slope of the %DET between basketball and WBP. This result indicated that the athletes are less fatigable during the task effort than the nonathletes. Normalized MDF slope decay exhibited similar results between the groups as %DET, while the slope of the normalized RMS failed to show any significant differences among the groups (p > 0.05). MDF and %DET could be useful for the evaluation of muscle fatigue in wheelchair basketball training. No conclusions about special training for WBP could be determined.

Mini-review: Robotic wheelchair taxonomy and readiness.

Robotic wheelchair research and development is a growing sector. This article introduces a robotic wheelchair taxonomy, and a readiness model supported by a mini-review. The taxonomy is constructed by power wheelchair and, mobile robot standards, the ICF and, PHAATE models. The mini-review of 2797 articles spanning 7 databases produced 205 articles and 4 review articles that matched inclusion/exclusion criteria. The review and analysis illuminate how innovations in robotic wheelchair research progressed and have been slow to translate into the marketplace.