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Mobile and Remote Monitoring of Seating Pressure for Wheelchair Users With SCI

Overview

About this study

The purpose of this study is to gather information on how a mobile pressure mapping system, when used at home on a daily basis, affects behaviors known to reduce risk of pressure ulcer development.

Participation eligibility

Participant eligibility includes age, gender, type and stage of disease, and previous treatments or health concerns. Guidelines differ from study to study, and identify who can or cannot participate. There is no guarantee that every individual who qualifies and wants to participate in a trial will be enrolled. Contact the study team to discuss study eligibility and potential participation.

Inclusion Criteria:

  • Participants will meet inclusion criteria if they live in the community.
  • Aged 18 or older, male or female, have paraplegia or quadriplegia due to a spinal cord injury that includes sensory loss below their level of injury, and require full-time wheelchair use for mobility.
  • Participants must demonstrate ability to independently access a smartphone and the required pressure mapping application on the smartphone. 
  • Participants must be able to tolerate sitting for a minimum of 6 hours per day, 7 days per week, and they must be able to perform weight shifts independently.
  • Participants must be able and willing to attend in-person visits at start and end of the study, about 4 weeks apart.

Exclusion Criteria:

  • Individuals will not be eligible for this study if there is an active stage 3, 4, or unstageable pressure ulcer as defined by the National Pressure Ulcer Advisory Panel definitions anywhere on their sitting surface.
  • They are not able to independently access the pressure mapping application on a smartphone, or if they are not able to complete an adequate weight shift without help.
  • Individual who use a specific custom-molded seat cushion (Ride Designs Custom Seat Cushion) will not be eligible due to challenges with conformability of the pressure sensing mat to the deep contours of this particular cushion. 
  • Individuals will also be excluded if they live in a long term care facility or group home and require 24 hours/day assistance.
  • Participants will be screened by phone or in person when being considered for enrollment into the study for cognitive impairments relating to memory and new learning. If a cognitive impairment is identified by a score of 3 or less on the Six-item Screen for Cognitive Impairment (Callahan, Unverzagt, Hui, Perkins, & Hendrie, 2002), the participants will not be able to participate in this study because there is an expectation of ability to learn new information and be able to recall the information over the study period.
  • Participants must be Mayo Clinic patients for access to the medical record.

 

Participating Mayo Clinic locations

Study statuses change often. Please contact the study team for the most up-to-date information regarding possible participation.

Mayo Clinic Location Status

Rochester, Minn.

Mayo Clinic principal investigator

Emma Fortune Ngufor, Ph.D.

Closed for enrollment

More information

Publications

  • A subject-specific step counting method with a high accuracy level at all walking speeds is needed to assess the functional level of impaired patients. The study aim was to validate step counts and cadence calculations from acceleration data by comparison to video data during dynamic activity. Custom-built activity monitors, each containing one tri-axial accelerometer, were placed on the ankles, thigh, and waist of 11 healthy adults. ICC values were greater than 0.98 for video inter-rater reliability of all step counts. The activity monitoring system (AMS) algorithm demonstrated a median (interquartile range; IQR) agreement of 92% (8%) with visual observations during walking/jogging trials at gait velocities ranging from 0.1 to 4.8m/s, while FitBits (ankle and waist), and a Nike Fuelband (wrist) demonstrated agreements of 92% (36%), 93% (22%), and 33% (35%), respectively. The algorithm results demonstrated high median (IQR) step detection sensitivity (95% (2%)), positive predictive value (PPV) (99% (1%)), and agreement (97% (3%)) during a laboratory-based simulated free-living protocol. The algorithm also showed high median (IQR) sensitivity, PPV, and agreement identifying walking steps (91% (5%), 98% (4%), and 96% (5%)), jogging steps (97% (6%), 100% (1%), and 95% (6%)), and less than 3% mean error in cadence calculations. Read More on PubMed
  • A robust method for identifying movement in the free-living environment is needed to objectively measure physical activity. The purpose of this study was to validate the identification of postural orientation and movement from acceleration data against visual inspection from video recordings. Using tri-axial accelerometers placed on the waist and thigh, static orientations of standing, sitting, and lying down, as well as dynamic movements of walking, jogging and transitions between postures were identified. Additionally, subjects walked and jogged at self-selected slow, comfortable, and fast speeds. Identification of tasks was performed using a combination of the signal magnitude area, continuous wavelet transforms and accelerometer orientations. Twelve healthy adults were studied in the laboratory, with two investigators identifying tasks during each second of video observation. The intraclass correlation coefficients for inter-rater reliability were greater than 0.95 for all activities except for transitions. Results demonstrated high validity, with sensitivity and positive predictive values of greater than 85% for sitting and lying, with walking and jogging identified at greater than 90%. The greatest disagreement in identification accuracy between the algorithm and video occurred when subjects were asked to fidget while standing or sitting. During variable speed tasks, gait was correctly identified for speeds between 0.1m/s and 4.8m/s. This study included a range of walking speeds and natural movements such as fidgeting during static postures, demonstrating that accelerometer data can be used to identify orientation and movement among the general population. Read More on PubMed
  • Background. People with spinal cord injury (SCI) are at increased risk of pressure ulcers due to prolonged periods of sitting. Concordance with pressure relieving movements is poor amongst this population, and one potential alternative to improve this would be to integrate pressure relieving movements into everyday functional activities. Objectives. To investigate both the current pressure relieving behaviours of SCI individuals during computer use and the application of an ergonomically adapted computer-based activity to reduce interface pressure. Design. Observational and repeated measures design. Setting. Regional Spinal Cord Injury Unit. Participants. Fourteen subjects diagnosed with SCI (12 male, 2 female). Intervention.Comparing normal sitting to seated movements and induced forward reaching positions. Main Outcome Measures. Interface pressure measurements: dispersion index (DI), peak pressure index (PPI), and total contact area (CA). The angle of trunk tilt was also measured. Results. The majority of movements yielded less than 25% reduction in interface pressure compared to normal sitting. Reaching forward by 150% of arm length during an adapted computer activity significantly reduced DI (P < 0.05), angle of trunk tilt (p<0.05), and PPI for both ischial tuberosity regions (P < 0.001) compared to normal sitting. Conclusion. Reaching forward significantly redistributed pressure at the seating interface, as evidenced by the change in interface pressures compared to upright sitting. Read More on PubMed
  • To assess the associations of race and socioeconomic status (SES) with pressure ulcers (PUs) after accounting for health care access among persons with spinal cord injury (SCI). Read More on PubMed
  • Multicenter prospective cohort study. Read More on PubMed
  • Monocentric cohort study. Read More on PubMed
  • The formation and underlying causes of pressure ulcers (PUs) are quite complex, with multiple influencing factors. However, by definition pressure ulcers cannot form without loading, or pressure, on tissue. Clinical interventions typically target the magnitude and/or duration of loading. Pressure magnitude is managed by the selection of support surfaces and postural supports as well as body posture on supporting surfaces. Duration is addressed via turning and weight shifting frequency as well as with the use of dynamic surfaces that actively redistribute pressure on the body surfaces. This article shows that preventative interventions must be targeted to both magnitude and duration and addresses the rationale behind several common clinical interventions--some with more scientific evidence than others. Read More on PubMed
  • Pressure ulcer incidence rates have remained constant despite advances in support surface technology. Interface shear stress is recognized as a risk factor for pressure ulcer development and is the focus of many shear reduction technologies incorporated into wheelchair cushions; however, shear reduction has not been quantified in the literature. We evaluated 21 commercial wheelchair seat cushions using a new methodology developed to quantify interface shear stress, interface pressure, and horizontal stiffness. Interface shear stress increased significantly with applied horizontal indenter displacement, while no significant difference was found for interface pressure. Material of construction resulted in significant differences in interface shear stress, interface pressure, and horizontal stiffness. This study shows that the existing International Organization for Standardization (ISO) 16840-2 horizontal stiffness measure provides similar information to the new horizontal stiffness measure. The lack of a relationship between interface shear stress and the overall horizontal stiffness measure, however, suggests that a pressure and shear force sensor should be used with the ISO 16840-2 horizontal stiffness measure to fully quantify a cushion's ability to reduce interface shear stress at the patient's bony prominences. Read More on PubMed
  • The aim of this article is to identify overarching principles that explain how daily lifestyle considerations affect pressure ulcer development as perceived by adults with spinal cord injury (SCI). Read More on PubMed
  • Pressure ulcers are a large problem in subjects who use a wheelchair for their mobility. These ulcers originate beneath the bony prominences of the pelvis and progress outward as a consequence of prolonged pressure. Interface pressure is used clinically to predict and prevent pressure ulcers. However, the relation between interface pressure and the development of pressure ulcers is not clear. A systematic review was performed to address the research question of whether interface pressure can be used to predict the development of pressure ulcers or to determine the prognosis of an ulcer once developed. Seven studies were identified that measured interface pressure and used the development or healing of pressure ulcers as an outcome measure. There appears to be a weak qualitative relation between interface pressure and the development of pressure ulcers. However, no conclusive clinical threshold for the interface pressure can be given. This, combined with the influence of individual characteristics, the low internal validity of interface pressure measurement for the prediction of pressure ulcers, and an incongruent relation between pressure magnitude and duration, results in the fact that no quantification of the predictive or prognostic value of interface pressure can be given. Read More on PubMed
  • This study examined how community-dwelling adults with spinal cord injury (SCI) respond in real-life circumstances after detecting a low-grade (Stage 1 or Stage 2) pressure ulcer. Read More on PubMed
  • To describe characteristics of recurrent pressure ulcers (PrUs) in veterans with spinal cord injury (SCI). Read More on PubMed
  • Measuring interface pressure (IP) is one way to characterize cushion performance in the clinic and laboratory. This study explored how the presence of four commercially available IP mats affected IP on and immersion of two buttocks models. We loaded seven cushions with each buttocks model and captured pressure data using FSA sensors (Vista Medical Ltd; Winnipeg, Manitoba, Canada). Analysis was performed to compare pressure magnitude and immersion. Overall, both pressure magnitude and immersion changed after mat introduction. A significant interaction existed between cushion and mat condition and cushion and model for all variables. Introducing an IP mat to the model-cushion interface alters the loading on the cushion. The mats bridged the contours of the model, causing a change in IP at the locations studied. Although immersion was statistically different between mat conditions, the magnitude of the difference was less than 1 mm once we accounted for the thickness of the mats. The significance of the cushion-mat interaction indicates that the mat effect differed across cushion design. Clinical and research users of pressure mats should consider the effect of mat presence, the effect of model design, and mat and buttocks interactions with cushions for successful use. Read More on PubMed
  • Recent technological improvements have led to increasing clinical use of interface pressure mapping for seating pressure evaluation, which often requires repeated assessments. However, clinical conditions cannot be controlled as closely as research settings, thereby creating challenges to statistical analysis of data. A multistage longitudinal analysis and self-registration (LASR) technique is introduced that emphasizes real-time interface pressure image analysis in three dimensions. Suitable for use in clinical settings, LASR is composed of several modern statistical components, including a segmentation method. The robustness of our segmentation method is also shown. Application of LASR to analysis of data from neuromuscular electrical stimulation (NMES) experiments confirms that NMES improves static seating pressure distributions in the sacral-ischial region over time. Dynamic NMES also improves weight-shifting over time. These changes may reduce the risk of pressure ulcer development. Read More on PubMed
  • To examine the daily-lifestyle influences on the development of pressure ulcers in adults with spinal cord injury (SCI). Read More on PubMed
  • To examine changes in seat-interface pressure with multiple sclerosis (MS) patients. Read More on PubMed
  • To examine the impact of pressure mapping technology on the clinical decisions of occupational therapists and to examine the role of the Braden Scale in assisting with the selection of pressure-reducing cushions. Read More on PubMed
  • To discuss the methodologic challenges related to pressure mapping in seating and to present a new approach to the analysis and interpretation of results: the frequency analysis approach. Read More on PubMed
  • Manual wheelchair configurations commonly include "squeezing" the wheelchair frame to improve balance for users with spinal cord injuries. This squeezing is achieved by lowering the rear portion of the seat relative to the front of the seat while maintaining the same back angle. The study's purpose was to examine the effect of increasing posterior seat inclination on buttock interface pressures. Read More on PubMed
  • Health service providers rely on pressure-relieving and pressure-reducing products to prevent pressure ulcers. This review critically examines interface pressure measurements, most commonly used to evaluate patient support surfaces. Read More on PubMed
  • To estimate the point prevalence of pressure sores in a community sample of spinal cord injured patients who were followed up by a spinal injuries unit and to evaluate whether self-management strategies were associated with decreased risk of pressure sores. Read More on PubMed
  • Pressure mapping systems offer a new technology to assist with pressure care assessment. Data output from such systems can be presented in three forms: numerical data, a three-dimensional grid and a colour-coded pressure map. Read More on PubMed
  • Determination of an appropriate wheelchair cushion to optimize loading on buttock tissue is crucial to pressure ulcer prevention. Standardized test methods aim to simplify selection by helping clinicians and users identify a class or category of cushions that will meet the important medical need of adequate pressure distribution. The objective of this project was to determine the test-retest reliability of interface pressure measurements taken using bench tests as opposed to human subject tests. Ten wheelchair cushions were tested following the methods for interface pressure measurement as defined in a draft International Organization for Standardization document. Dispersion index, contact area, percent force in the ischial regions, peak pressure index, and seating pressure index-standard deviation are reliable measures. Average pressure is reliable but not very volatile between cushions. The data also indicate that peak pressure, seating pressure index-skew (SPI-sk), and the other five percent force regions are not reliable. Certain bench interface pressure variables were found to have adequate intralaboratory repeatability. Interlaboratory reliability must also be tested. If a bench interface pressure test is used to indicate cushion performance, its validity should also be studied. Research is underway to relate interface pressure variables to clinical measurements of wheelchair users. Once validity is shown, standardized test results can then be used by clinicians to simplify and improve the wheelchair cushion selection process. Read More on PubMed
  • Measurement of interface (or contact) pressure is important in assessing tissue viability in relation to pressure sore prevention and may be achieved through pressure mapping techniques. This article reports on two pilot studies using the Force Sensing Array pressure mapping system in a laboratory setting. The purpose of Study 1 was to examine the consistency of readings from the system across 1-min trials of repositioning, and Study 2 aimed to investigate changes in interface readings over a 20-min sitting period. Analyses on measurements of average pressure (mean of all sensor values) and maximum pressure (highest individual sensor value) were performed using the t test and repeated-measures analysis of variance. The results demonstrated that the use of average and maximum pressure measurements reflected only low reliability and that 6 min was likely to be the optimal sitting time required before stable pressure measurement. However, because of the limitations of using small convenience samples of healthy participants (n = 44 for Study 1, n = 20 for Study 2), these studies should be replicated with larger samples of healthy participants and then verified with disabled populations before adoption into clinical practice. Read More on PubMed
  • Although no gold standard for preventing or treating pressure ulcers has been established, data from clinical trials indicate specific efforts are worthwhile. Preventive strategies include recognizing risk, decreasing the effects of pressure, assessing nutritional status, avoiding excessive bed rest, and preserving the integrity of the skin. Treatment principles include assessing the severity of the wound; reducing pressure, friction, and shear forces; optimizing wound care; removing necrotic debris; managing bacterial contamination; and correcting nutritional deficits. Read More on PubMed
  • To investigate the relation between pressure ulcer incidence and buttock-wheelchair seat cushion interface pressure measurements. Read More on PubMed
  • A field study of the relationship between skin sores and life adjustment after spinal cord injury (SCI) was conducted by surveying a sample of more than 1000 participants with SCI. Read More on PubMed
  • Whether treated with surgery or by conservative, nonsurgical measures, pressure ulcers recur in 5% to 91% of spinal cord injured (SCI) patients. Factors other than the surgical technique used or the standard conservative management provided may be responsible. A retrospective study of 176 SCI patients with a history of one or more pressure ulcers was conducted at the Department of Veterans Affairs Medical Center at Castle Point, N.Y. Approximately 35% of patients who received either surgical or nonsurgical treatment had a recurrence. Patients who smoked and patients with diabetes or cardiovascular disease had higher recurrence rates. Read More on PubMed
  • Two methods can be used to assess the relative pressure-relieving/pressure-reducing effects of clinical support surfaces. The interaction occurring at the interface between the human body and the support surface--known as the interface pressure--can be measured with an interface pressure system. Reactive hyperemia, the physiologic response to pressure, can be measured with thermography and laser Doppler flowmetry. Using mannequins and human subjects that represent typical body types in the older population, a protocol was developed for collecting data on the effects of support surfaces on interface pressure and reactive hyperemia. Read More on PubMed
  • The prevalence and correlates of pressure ulcers in terms of their number, severity, and anatomical location were studied in a community-based sample of 100 men and 40 women with spinal cord injury. Thirty-three percent (n = 46) presented with one or more ulcers of at least one stage I severity when visually examined. Twenty-one individuals had more than one ulcer, the maximum number of ulcers being seven. Of 87 ulcers for which severity ratings were available, 30 (34.5%) were stage I, 33 (37.9%) were stage II, and 24 (27.6%) were either stage III or IV. Individuals with an ulcer exhibited more paralysis and were more dependent on others in activities of daily living. A greater proportion of blacks had more severe ulcers (stages III and IV) than their white counterparts. Persons with more severe ulcers incurred their injury later in life, and had significantly lower mean scores on the Occupation and Mobility dimensions of the Craig Handicap Assessment and Reporting Technique. The findings suggest that factors governing initial development of a pressure ulcer differ in part from those responsible for an ulcer progressing in severity. Read More on PubMed
  • The incidence and effect of pressure sores on the disabled and elderly population have created a challenge to physicians and health care professionals, from emergency departments to rehabilitation units, and in the community. If not prevented, the morbidity and mortality of patients and the direct and indirect costs to both patients and the health care system are radically increased. In this article we define the impact on our health care system of pressure sores, provide an overview of a multifaceted approach to their prevention and management, and introduce successful behavioral and educational approaches for patients with chronic, recurrent sores. A coordinated approach with patients as informed participants and their care givers enhances the chances for success. Read More on PubMed
  • We carried out a prospective study to determine the association between immobilization in the immediate postinjury period and the development of pressure ulcers in spinal cord-injured patients following their admission to Charity Hospital, New Orleans. Of 39 patients consecutively admitted to the hospital, 23 (59%) developed a grade one ulcer within 30 days, mostly in the sacral region (57%), the peak time of onset being day 4 postinjury (6/23 cases). In partial support of an earlier retrospective study (Linares HA, Mawson AR, Suarez E, Biundo JJ Jr: Association between pressure sores and immobilization in the immediate post-injury period. Orthopedics 1987;10:571-573), duration of unrelieved pressure prior to ward admission was significantly associated with ulcers developing within the first eight days of injury (P = 0.04), but not with ulcers developing during the entire 30-day observation period (P = 0.09). Time on the spinal board was also significantly associated with ulcers developing within 8 days (P = 0.01), but not with ulcers developing within 30 days (P = 0.09). An unexpected finding was the significant inverse association between systolic blood pressure and the development of ulcers both within 8 days (P = 0.03) and within 30 days (P = 0.02), suggesting that reduced tissue perfusion increases the spinal cord-injured patient's susceptibility to pressure ulcers. Read More on PubMed

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