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Biomedical subjects

Stephen Sprigle

Publications and source records attributed to Stephen Sprigle.

12 recordsLinked to original sources
PubMed2004

Effect of seat inclination on seated pressures of individuals with spinal cord injury.

BACKGROUND AND PURPOSE: 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. SUBJECTS: Nine male and 5 female subjects (mean age=37 years, SD=11.2, range=19-55) with complete thoracic or lumbar spinal cord injury were tested. METHODS: Subjects sat on a pressure mat placed over a foam cushion. Pressure readings were taken at seat angles reflecting seat height decreases of 0, 5.1, 7.6, and 10.2 cm (0, 2, 3, and 4 in) of the rear of the seat relative to the front of the seat. An analysis of variance and a Duncan multiple range test were used for data analysis. RESULTS: No meaningful differences were found in measurements of interface pressure (dispersion index, contact area, and seat pressure index), total force on seat, or peak pressure index with posterior seat inclination. DISCUSSION AND CONCLUSION: The data indicate no meaningful evidence that squeezing a wheelchair frame increases seat interface pressures.

Adult↗
PubMed2003

Development and testing of a pelvic goniometer designed to measure pelvic tilt and hip flexion.

OBJECTIVE: To determine the reliability and validity of a pelvic goniometer designed to measure the pelvic tilt and hip flexion during seated posture. BACKGROUND: Assessment of the seated posture requires measurement of the pelvis and hip. Determining accurate pelvic tilt and hip flexion angles during sitting is often difficult using standard techniques. A pelvic goniometer has been designed to measure pelvic tilt and hip flexion angle of persons in a seated posture. METHODS: VALIDATION of the pelvic goniometer was done radiographically. Ten male volunteers sat in three postures--erect, forward or anterior tilt, and posterior tilt. Pelvic tilt and hip angle were recorded using radiographs and the pelvic goniometer. Reliability of pelvic and conventional goniometers was done using seated nondisabled subjects with physical therapists performing measurements. RESULTS VALIDATION: the average differences and correlation between the pelvic goniometer and radiographic measures were as follows--pelvic tilt: -4.9 degrees, 0.93; hip angle 1.2 degrees, 0.81. Reliability: average range of hip angle across three measures was about 3 degrees for both goniometers. CONCLUSIONS: The data indicate that the pelvic goniometer has utility in measuring pelvic tilt and hip angle, especially within the seated posture. Because it measures both pelvic tilt and hip angle, the pelvic goniometer has an advantage over conventional goniometers that only measure the latter. RELEVANCE: A valid and reliable tool that measures pelvic tilt and hip angle of persons in a seated posture is needed for clinical research and practice. Its applications include wheelchair seating evaluations and ergonomic assessments of seated workers.

Adult↗
PubMed2003

Cost analyses in assistive technology research.

Economic evaluation has become one of the principal methodologies in outcomes research within the health care field in general and specifically in assistive technology. Efforts to define and develop a consistent methodology for assistive technology economic evaluations have been hampered by lack of familiarity with the various terms and concepts associated with cost analysis, an essential aspect of economic evaluations. Adapting these concepts, which were constructed to suit a medical model, to the needs of the assistive technology field has been a challenge as well. This article outlines terms and concepts basic to cost analysis. The authors then consider five studies that relate costs to outcomes in order to illustrate the challenges, choices, and trade-offs researchers make when adapting this methodology to assistive technology. The article concludes by seeking to stimulate further discussion of the complexity inherent in assessing costs in assistive technology outcomes research and calling for the development of a standardized and consistent economic evaluation methodology.

Costs and Cost Analysis↗
PubMed2003

Reliability of bench tests of interface pressure.

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.

Equipment Design↗
PubMed2003

Reliability of the ISO wheelchair cushion test for loaded contour depth.

Standardized test methods that report cushion characteristics and performance can simplify cushion selection by helping clinicians and users identify types of cushions that may meet a user's needs. The loaded contour depth (LCD) test is one of the test methods included in the International Organization for Standardization (ISO) standards for wheelchair cushions. LCD measures the depth of immersion into a cushion. The objective was to determine the reliability of LCD and overload deflection measurements. LCD and overload deflection tests were repeated on 17 cushions. Intraclass correlation coefficient (ICC) and repeatability coefficient (RC) were calculated. The reliability of LCD (ICC = 0.98; RC = 0.21) and overload depth (RC = 0.15) were very high. LCD measures can reliably be used to differentiate cushions that vary by at least 1 cm. The overload test can be used as a criterion-referenced measure, but it is not sensitive to variation.

Equipment Design↗
PubMed2003

Relationships among cushion type, backrest height, seated posture, and reach of wheelchair users with spinal cord injury.

BACKGROUND: Seated posture and trunk control are important factors affecting upper extremity (UE) function of wheelchair users. A stable pelvis and trunk are required to provide a base from which UE movement occurs, but, conversely, the ability to move one's trunk and pelvis can increase functional ranges of motion. For wheelchair users, balancing sufficient trunk support with adequate trunk mobility has important functional and medical consequences. OBJECTIVE: To determine the effect of cushion and backrest height on posture and reach and to determine the relationship between posture and UE reach using a randomized 2 x 3 repeated-measures factorial design. METHODS: Twenty-two subjects with spinal cord injury were tested in 6 configurations, including 3 types of cushions (segmented air, contoured viscous fluid/foam, and air/foam) and 2 of 3 backrest heights (referenced to T12, inferior scapular angle, and scapular spine) while performing unilateral and bilateral reaching tasks. Seated posture (pelvic tilt and torso angle) and American Spinal Injury Association (ASIA) score were also measured. RESULTS: Pelvic tilt and ASIA score were significant predictors of reach. No evidence was found indicating cushion type or backrest height affected reach or posture. No consistent patterns of posture were found across cushion types or backrest heights. CONCLUSIONS: The posture adopted by wheelchair users is a more important influence on UE reach than are the cushion or backrest height used. Sitting with increased posterior pelvic tilt enhanced stability and permitted greater reach. Because individuals adopt different postures when using different cushions and backrest heights, clinicians should monitor posture while assessing seating and function of wheelchair users.

Adolescent↗
PubMed2003

Analysis of localized erythema using clinical indicators and spectroscopy.

Localized erythema is regularly used as an indicator of post-ischemic events, including reactive hyperemia and Stage I pressure ulcers. The National Pressure Ulcer Advisory Panel definition of a Stage I ulcer includes both visual and nonvisual indicators in part to improve identification in darkly pigmented skin. A prospective, repeated-measures design was used to collect information on pressure-induced erythema that includes reactive hyperemia and Stage I pressure ulcers with an emphasis on distinguishing indicators in light and dark skin The relationships among clinical indicators (skin assessments) and results from tissue reflectance spectroscopy, as well as the clinical utility of spectroscopy for discerning tissue blanching status, were examined in a convenience sample of 76 inpatients and outpatients (95 test/control site pairs). Chi-square analysis and generalized logistic models were used to identify relationships and distinguishing characteristics of erythema. Analysis of variance was used to analyze blanching using spectroscopy. Nonblanching sites were more likely to be persistent erythema (c2=5.3; P = 0.021) but exhibited no relationships to temperature, tissue resilience, or disability. Erythema in subjects with dark skin was more likely to be nonblanching and have poor resilience. Spectrographic analysis of blanching found significant differences across skin pigmentation (P = 0.0001) and blanching status (P = 0.019). These results reinforce the belief that dark skin must be assessed differently than light skin and indicate that clinicians should use persistence of erythema rather than blanching status to judge incipient pressure ulcers. These results validate the use of visual and nonvisual indicators included in the National Pressure Ulcer Advisory Panel Stage I pressure ulcer definition.

Adult↗
PubMed2002

Characterizing reactive hyperemia via tissue reflectance spectroscopy in response to an ischemic load across gender, age, skin pigmentation and diabetes.

PURPOSE: Pressure ulcers represent a major secondary complication for amputees with diabetes and further complications may arise since ulcers are particularly hard to heal in this population. This study characterized the hyperemic response to a localized ischemic load in people with diabetes and amputation and compared it to that of subjects without diabetes or amputation. SUBJECTS: Case-control study matching subjects by gender, age, skin pigmentation, and smoking status. METHODS: Applying 150 mmHg to the patellar tendon for 10 minutes induced reactive hyperemia (RH). Tissue reflectance spectroscopy measured hemoglobin (HbO(2)) concentration in tissue before, during and after application of pressure. Refill time, Maximum HbO(2), Time@Max HbO(2), RH area and RH half-life characterized the RH response and were analyzed using ANOVA. All values up to a level of p <0.1 are presented. RESULTS: Analysis included responses from 88 subjects. RH magnitude and temporal parameters varied across skin pigmentation; smokers showed a decreased RH magnitude; vasodilator users had greater RH temporal parameters; no evidence of differences were found across disease state or age. CONCLUSION: Decreased RH response in smokers and subjects with dark skin might indicate a reduced ability to recover from ischemia. The lack of difference in RH response between subjects with and without diabetes was consistent with studies using other disability groups and corroborates the theory that RH is locally mediated.

Adult↗
PubMed2002

Development of a noninvasive measure of pelvic and hip angles in seated posture.

OBJECTIVE: To develop a valid noninvasive means to measure pelvic tilt and hip angle in seated posture. DESIGN: Validation cohort study using radiographs as a criterion standard for pelvic posture. SETTING: Rehabilitation hospital. PARTICIPANTS: Volunteer sample of 10 adult men with no known physical disability. INTERVENTIONS: Radiographs were taken as subjects sat in erect, anterior, and posterior postures. An electromagnetic tracking device was as a pointer to digitize the anterior superior and posterior superior iliac spines and as a 6 degrees of freedom (df) sensor mounted on the thigh and sacrum. MAIN OUTCOME MEASURES: Variables included pelvic tilt and hip flexion angle. Intra- and interrater reliability of radiographic measures was determined by using intraclass correlation coefficient comparison of the results from 2 investigators. Validity was determined by comparing noninvasive measures of pelvic and hip angles to radiographic measures by using correlation, analysis of variance (ANOVA), and regression. RESULTS: Reliability of radiographic measures of pelvic tilt and hip angles were >/=.98. Pelvic tilt comparison: pointer: r=.89, R(2)=.80; 6-df sensor: r=.91, R(2)=.83; hip angle comparison using 6-df sensor: r=.78 with average difference of 4.25 degrees. ANOVA showed that differences between all invasive and noninvasive measures did not differ significantly (P>.05). CONCLUSION: Results indicated excellent reliability of radiographic analysis techniques and represented an improvement over previously published techniques. Noninvasive measures of pelvic tilt and hip angle were shown to be valid.

Adult↗
PubMedDate not supplied

Pressure-related deep tissue injury under intact skin and the current pressure ulcer staging systems.

OBJECTIVE: To identify how current pressure ulcer staging systems and experts describe pressure-related deep tissue injury under intact skin in the published research literature. DESIGN: A systematic review of published English-language literature as of November 2002 with the words decubitus or pressure ulcer(s) in the title. Additional relevant articles were identified by National Pressure Ulcer Advisory Panel members and were included in the analysis. An expert commentary was developed by iterative review by the National Pressure Ulcer Advisory Panel members. MAIN OUTCOME MEASURES: Manuscripts were reviewed for staging systems cited or described, definitions of Stage I pressure ulcers, and descriptions or definitions of pressure-related deep tissue injury under intact skin. MAIN RESULTS: Ninety-four relevant articles were identified. Seventy-three articles (78%) described a staging system, and 55 of 73 (75%) cited the staging definitions from Shea, the National Pressure Ulcer Advisory Panel, or the Agency for Health Care Policy and Research. The National Pressure Ulcer Advisory Panel's staging definitions were the most frequently cited overall. Twenty-three articles (25%) included some discussion that could be interpreted as relevant to the topic of pressure-related deep tissue injury under intact skin; however, no consistency in definitions of Stage I pressure ulcers or terminology for pressure-related deep tissue injury under intact skin was found. CONCLUSIONS: Several pressure ulcer staging systems are frequently cited, but none define pressure-related deep tissue injury under intact skin. The National Pressure Ulcer Advisory Panel recommends using the terms "pressure-related deep tissue injury under intact skin" or "deep tissue injury under intact skin" for describing these lesions and encourages investigators to establish the epidemiology and natural history of these lesions.

Humans↗