No abstract

Abstract-This study considers the effects of seated posture and body orientation on the pressure-distribution and surface shear (tangential) forces acting at the bodyseat interface. Nine postures typically assumed by wheelchair users were studied. Comparisons were made within and between two study groups, made up of 12 subjects with spinal cord injuries (SCI) and 10 nondisabled subjects. Both interface pressure and the surface shear were measured simultaneously in each of nine reproducible, seated postures. The same seat cushion was used for all trials. The Oxford Pressure Monitor, a pneumatic cell device, was used to measure and record the interface pressures. Instrumentation for measuring and recording the surface shear force was constructed specifically for the study. Analysis consisted of statistically comparing changes in pressure values and shear forces derived from eight sitting postures with reference to values recorded in a defined neutral sitting posture. The pressure-distribution findings suggest that in the postures studied SCl subjects have maximum pressures that are higher than nondisabled subjects in all postures, ranging from 6% to 46% depending on the posture. Maximum pressures can be reduced by postural changes: forward flexion to 50°, -9%; backrest recline to 120°, -12%; and, full body tilt, -11 %. On average, the §GI group members have peak pressure gradients (PPG) that are 1.5 to 2.5 greater than the nondisabled group. The maximum reduction in PPG occurred at backrest recline of 120°, -18%. only recline of 20" causes a 25% increase in the surface shear force. These results suggest that caution must be taken when using nondisabled subjects as surrogates for people with SCI because of the inherent differences between the groups. Also, researchers and clinicians should recognize that posture and body orientation in space are additional variables that can have a profound effect on the interaction between a seated person and his or her supporting surface.

With prospects improving for experimental therapeutics aimed at postponing the onset of illness in preclinical carriers of the Huntington's disease (HD) gene, we assessed agreement among experienced clinicians with respect to the motor manifestations of HD, a relevant outcome measure for preventive trials in this population. Seventy-five clinicians experienced in the evaluation of patients with early HD and six non-clinicians were shown a videotape compiled from the film archives of the United States-Venezuela Collaborative HD Research Project. Observers were asked to rate a 2-3-minute segment of the motor examination for each of 17 at-risk subjects. The rating scale ranged from 0 (normal) to 4 (unequivocal extrapyramidal movement disorder characteristic of HD). As measured by a weighted kappa statistic, there was substantial agreement among the 75 clinicians in the judgment of unequivocal motor abnormalities comparing scale ratings of 4 with ratings that were not 4 (weighted kappa = 0.67; standard error (SE) = 0.09). Agreement among the non-clinicians was only fair (weighted kappa = 0.28; SE = 0.10). Even under the artificial conditions of a videotape study, experienced clinicians show substantial agreement about the signs that constitute the motor manifestations of illness in subjects at risk for HD. We expect these findings to translate to a similar level of interobserver agreement in the clinical trial setting involving experienced investigators examining live patients.

This pilot study was designed to measure the effects of individually prescribed wheelchair systems on posture and reach, mobility, quality of life, and satisfaction with technology for residents of long-term care facilities. Thirty persons 60 years of age or older who resided permanently in a long-term care facility and who used seating and mobility systems for 6 hours or more each day were recruited for this project. Outcomes included timed independent mobility, forward and lateral reach, quality of life, and satisfaction with assistive technology. The study used semicrossover design with participants measured three times. Measurements were first made in the existing seating and mobility system and a second time immediately after participants were provided with individually prescribed seating and mobility systems. The final measurement was 3 months after the delivery of the individually prescribed system. Results indicated that individually fitted wheelchair systems for elderly residents of long-term care facilities are beneficial. Participants had less difficulty independently propelling their systems and increased forward reach, quality of life for social function and physical role, and satisfaction with the new wheelchair technology. Persons residing in extended care facilities benefit from receiving individually prescribed wheelchair systems. The individual systems enhance elderly persons' independent mobility, functional reach, feeling of well-being, and satisfaction with their assistive technology.