Analysis of pressure distribution at the body–seat interface in able-bodied and paraplegic subjects using a deformable active contour algorithm

Aïssaoui, Rachid; Kauffmann, Claude; Dansereau, J.; Guise, Jacques A. de

doi:10.1016/s1350-4533(01)00052-2

Cited by 46 publications

(40 citation statements)

References 41 publications

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“…These findings are generally consistent with other studies that identified differences in interface pressures between SCI and AB subject populations (17)(18)(19). The high linearity of the responses means that no threshold point (eg, 45u of tilt) beyond which the load dropped dramatically occurred in any of the 3 variable positioning methods.…”

Section: Discussionsupporting

confidence: 92%

Load Redistribution in Variable Position Wheelchairs in People With Spinal Cord Injury

Sprigle

Maurer

Soneblum

2010

The Journal of Spinal Cord Medicine

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Background/Objective: Tilt and recline variable position seating systems are most commonly used for pressure relief to decrease potential for skin breakdown. This study provides quantitative information on the magnitudes of loading on the seat and back during phases of tilt, recline, and standing. The objective of this study was to show that the amount of force reduction at the seat would differ across these 3 methods within their respective clinical ranges. Participants: Six able-bodied (AB) subjects (2 men, 4 women) with a median age of 25 years, and 10 subjects (8 men, 2 women) with spinal cord injury (SCI) with a median age of 35.5 years. Methods: Subjects sat on a power wheelchair with Tekscan pressure mats placed underneath a foam backrest and cushion. Data were collected at 5 positions for each method. Order of position and method tested were randomized. Linear regressions were used to calculate the relationships of normalized seat and backrest forces to seat and backrest angles for each chair configuration. Results: Normalized seat loads had strong linear relationships with the angles of change in tilt, recline, and standing for both groups. Maximum decreases in seat load occurred at full standing and full recline in the SCI subjects and in full standing in the AB subjects. Loads linearly increased on the back during tilt and recline and linearly decreased during standing for both groups. Conclusions: Standing and recline offered similar seat load reductions at their respective terminal positions. Standing also reduced loading on the backrest. Recognizing that each method had clinical benefits and drawbacks, the results of this study indicate that tilt, recline, and standing systems should be considered as a means of weight shifting for wheelchair users.

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Section: Discussionsupporting

confidence: 92%

Load Redistribution in Variable Position Wheelchairs in People With Spinal Cord Injury

Sprigle

Maurer

Soneblum

2010

The Journal of Spinal Cord Medicine

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“…In all cases, this area was extremely small: in control subjects a mere 17 cm 2 and only 10 cm 2 in SCI subjects. This corresponded well with the findings of Aissaoui et al [1], who reported that the area supported by the ischial tuberosity region in SCI subjects was approximately half that of the able-bodied subjects. As the total surface area was nearly 3 times larger in control subjects than in SCI subjects, the maximum loading area does not decrease proportionally.…”

Section: Discussionsupporting

confidence: 92%

“…The maximum pressure on the wheelchair was measured at a mean of 245 g/cm 2 , equivalent to 180 mmHg. This again corresponds to the findings of Aissaoui et al [1], who reported SCI subjects as having a maximum pressure of 199-212 mmHg, equivalent to 271-288 g/cm 2 , in a standard chair with a flat-foam cushion. The pressure on the hard surface of 1,205 g/cm 2 , equivalent to 886 mmHg, also correlates with results from Thorfinn et al [16], who reported a maximum pressure of 11.7 N/cm 2 , equivalent to 877 mmHg or 1,192 g/cm 2 , in SCI subjects sitting on a glass plate.…”

Section: Discussionsupporting

confidence: 90%

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Measuring seating pressure, area, and asymmetry in persons with spinal cord injury

et al. 2003

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IntroductionSpinal cord injury (SCI) occurs in a substantial proportion of trauma. A study from major trauma centers in the United States reports that SCI occurred in 2.6% of trauma patients, or approximately 1 in 40 patients, reported between 1982 and 1989, of whom 79% were male [4]. Wheelchair-ambulating patients with SCI are often susceptible to joint pain, spine deformity, or pressure sores [5,6,9,10,13].Pressure on the seating area alters dramatically after SCI. The muscle atrophy that often results from SCI, combined with the loss of other soft tissues, reduces the area of the surface and the distribution of pressure to the underlying structures. Pressure, defined as force per unit area, increases rapidly with decreasing contact area. High pressures on the seating surface lead to pressure sores, a major concern of persons with SCI for both health and quality-of-life reasons.Asymmetry of static sitting in SCI has been little studied in the literature. Complications such as spine deformity, a common secondary effect of muscle imbalance, and loss of sensory ability and perception may lead to an asymmetry in loading. This asymmetry will further exacerbate the consequences of high pressures on the loading area [13].Abstract The goal of this study was to measure characteristics of seat loading in manual wheelchair users with complete spinal cord injury (SCI). Pressure distribution on the seating area of 25 adult males with SCI and eight non-injured adult males was measured in a relaxed and an upright posture on a standardized hard surface. Subjects with SCI were also tested in their wheelchairs. Maximum pressure, contact area, area of the highest pressure, and three asymmetry indices were compared. Subjects with SCI have higher pressure distributed over a smaller area, have a much smaller contact area, and distribute the loading more asymmetrically than non-injured subjects. Upright posture only corrects for some loading problems, while the wheelchair corrects for more loading parameters. Routine clinical seat loading evaluation may lead to improved chair and cushion selection for patients with SCI and may even alert clinicians to patients at high risk for complications due to high or unbalanced loads.

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“…Clinical evidence shows that turning patients regularly (e.g., every 2-4 h) can lower the incidence of pressure ulcers [3], and sitting-induced pressure can be relieved by performing wheelchair tilt and recline functions [3,[5][6]. The wheelchair tilt function refers to the adjustment of the seat orientation angle (measured against the ground) while keeping the seat-to-back angle unchanged.…”

Section: Introductionmentioning

confidence: 99%

Development of intelligent model for personalized guidance on wheelchair tilt and recline usage for people with spinal cord injury: Methodology and preliminary report

Jones

Jan

2014

J Rehabil Res Dev

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Abstract-Wheelchair tilt and recline functions are two of the most desirable features for relieving seating pressure to decrease the risk of pressure ulcers. The effective guidance on wheelchair tilt and recline usage is therefore critical to pressure ulcer prevention. The aim of this study was to demonstrate the feasibility of using machine learning techniques to construct an intelligent model to provide personalized guidance to individuals with spinal cord injury (SCI). The motivation stems from the clinical evidence that the requirements of individuals vary greatly and that no universal guidance on tilt and recline usage could possibly satisfy all individuals with SCI. We explored all aspects involved in constructing the intelligent model and proposed approaches tailored to suit the characteristics of this preliminary study, such as modeling research participants, using machine learning techniques to construct the intelligent model, and evaluating the performance of the intelligent model. We further improved the intelligent model's prediction accuracy by developing a two-phase feature selection algorithm to identify important attributes. Experimental results demonstrated that our approaches showed promise: they could effectively construct the intelligent model, evaluate its performance, and refine the participant model so that the intelligent model's prediction accuracy was significantly improved.Key words: artificial neural network, C4.5 decision tree, machine learning, pressure ulcer, random forest, skin blood flow, skin perfusion, spinal cord injury, support vector machine, wheelchair tilt and recline.

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Analysis of pressure distribution at the body–seat interface in able-bodied and paraplegic subjects using a deformable active contour algorithm

Cited by 46 publications

References 41 publications

Load Redistribution in Variable Position Wheelchairs in People With Spinal Cord Injury

Load Redistribution in Variable Position Wheelchairs in People With Spinal Cord Injury

Measuring seating pressure, area, and asymmetry in persons with spinal cord injury

Development of intelligent model for personalized guidance on wheelchair tilt and recline usage for people with spinal cord injury: Methodology and preliminary report

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