Chair design affects how older adults rise from a chair

Analysis of Relationship between Natural Standing Behavior of Elderly People and a Class of Standing Aids in a Living Space

As the world’s population ages, technology-based support for the elderly is becoming increasingly important. This study analyzes the relationship between natural standing behavior measured in a living space of elderly people and the classes of standing aids, as well as the physical and cognitive abilities contributing to household fall injury prevention. In total, 24 elderly standing behaviors from chairs, sofas, and nursing beds recorded in an RGB-D elderly behavior library were analyzed. The differences in standing behavior were analyzed by focusing on intrinsic and common standing aid characteristics among various seat types, including armrests of chairs or sofas and nursing bed handrails. The standing behaviors were categorized into two types: behaviors while leaning the trunk forward without using an armrest as a standing aid and those without leaning the trunk forward by using an arrest or handrail as a standing aid. The standing behavior clusters were distributed in a two-dimensional map based on the seat type rather than the physical or cognitive abilities. Therefore, to reduce the risk of falling, it would be necessary to implement a seat type that the elderly can unconsciously and naturally use as a standing aid even with impaired physical and cognitive abilities.

Effects of seat height on whole-body movement and lower limb muscle power during sit-to-stand movements in young and older individuals

Sit-to-stand (STS) movements from low seat height are not easily executed by older individuals. Although young individuals increase their lower limb muscle power (LLMP) based on the product of the ground reaction force (GRF) and center of mass velocity (CoMv) during STS movement from a low seat height, it remains unclear whether seat height has an effect on LLMP during STS movement in older individuals. The present study aimed to investigate differences in the LLMP during STS movements when seat height is lowered between young and older individuals. Twelve older and twelve height-matched young individuals were instructed to perform STS movements from low (20 cm), middle (40 cm), and high (60 cm) seat heights. STS movement and GRF were obtained by a motion analysis system and force plates. In the low-seat-height condition, the forward and upward LLMPs and the upward CoMv were significantly lower in older individuals than those in young individuals, but the forward CoMv was not. The completion time of STS movement from a low seat height was significantly longer in older individuals than in young individuals. Our findings suggest that the slower upward CoMv due to the lower upward LLMP extends the completion time of STS movement from a low seat height in older individuals. Furthermore, in the low-seat-height condition, older individuals may move their center of mass (CoM) forward in a different way when compared with young individuals, and they may not use forward LLMP for moving CoM forward.

Quantitative Comparison of Human and Software Reliability in the Categorization of Sit-to-Stand Motion Pattern

The Sit-to-Stand (STS) test is used in clinical practice as an indicator of lower-limb functionality decline, especially for older adults. Due to its high variability, there is no standard approach for categorising the STS movement and recognising its motion pattern. This paper presents a comparative analysis between visual assessments and an automated-software for the categorisation of STS, relying on registrations from a force plate. 5 participants (30 ± 6 years) took part in 2 different sessions of visual inspections on 200 STS movements under self-paced and controlled speed conditions. Assessors were asked to identify three specific STS events from the Ground Reaction Force, simultaneously with the software analysis: the start of the trunk movement (Initiation), the beginning of the stable upright stance (Standing) and the sitting movement (Sitting). The absolute agreement between the repeated raters' assessments as well as between the raters' and software's assessment in the first trial, were considered as indexes of human and software performance, respectively. No statistical differences between methods were found for the identification of the Initiation and the Sitting events at self-paced speed and for only the Sitting event at controlled speed. The estimated significant values of maximum discrepancy between visual and automated assessments were 0.200 [0.039; 0.361] s in unconstrained conditions and 0.340 [0.014; 0.666] s for standardised movements. The software assessments displayed an overall good agreement against visual evaluations of the Ground Reaction Force, relying, at the same time, on objective measures.

Older Adults with Weaker Muscle Strength Stand up from a Sitting Position with More Dynamic Trunk Use

The ability to stand up from a sitting position is essential for older adults to live independently. Body-fixed inertial sensors may provide an approach for quantifying the sit-to-stand (STS) in clinical settings. The aim of this study was to determine whether measurements of STS movements using body-fixed sensors yield parameters that are informative regarding changes in STS performance in older adults with reduced muscle strength. In twenty-seven healthy older adults, handgrip strength was assessed as a proxy for overall muscle strength. Subjects were asked to stand up from a chair placed at three heights. Trunk movements were measured using an inertial sensor fixed to the back. Duration, angular range, and maximum angular velocity of STS phases, as well as the vertical velocity of the extension phase, were calculated. Backwards elimination using Generalized Estimating Equations was used to determine if handgrip strength predicted the STS durations and trunk kinematics. Weaker subjects (i.e., with lower handgrip strength) were slower during the STS and showed a larger flexion angular range and a larger extension angular range. In addition, weaker subjects showed a greater maximum angular velocity, which increased with lower seat heights. Measurements with a single inertial sensor did reveal that older adults with lower handgrip strength employed a different strategy to stand up from a sitting position, involving more dynamic use of the trunk. This effect was greatest when elevating body mass. Trunk kinematic parameters were more sensitive to reduced muscle strength than durations.

Seating in aged care: Physical fit, independence and comfort

Objectives:

This research was intended to provide a greater understanding of the context and needs of aged care seating, specifically:

Methods:

Methods included a chair dimension audit, interviews with residents, experts and carers and observations of aged care residents getting into chairs, sitting in them and getting out.

Results:

Results showed that residents, experts and carers all prefer chairs which are above the recommended height for older people so that they will be able to get out of them more easily. Armrests were essential for ease of entry and egress. However, many residents struggled with chairs which were also too deep in the seat pan so that they could not easily touch the floor or sit comfortably and were forced to slump. Most residents used cushions and pillows to relieve discomfort where possible.

Conclusion:

The implications of these issues for chair design and selection are discussed. Variable height chairs, a range of chairs of different heights in each space and footrests could all address the height problem. Chair designers need to address the seat depth problem by reducing depth in most aged care specific chairs, even when they are higher. Armrests must be provided but could be made easier to grip. Addressing these issues would increase access to comfortable yet easy-to-use chairs for a wider range of the aged care population.

The coordination of joint movements during sit-to-stand motion in old adults: the uncontrolled manifold analysis

OBJECTIVE

Sit-to-stand motion (STS) is a dynamic motion utilized in fundamental activities of daily living and requires extensive joint movement in the lower extremities and the trunk and coordination of multiple body segments. The present study aimed to investigate whether aging affects the motor coordination of joint movements required to stabilize the horizontal and vertical movement of center of mass using the uncontrolled manifold (UCM) analysis.

METHOD

We recruited 39 older adults with no musculoskeletal and/or neuromuscular conditions that affected STS, along with 21 healthy younger adults. All subjects performed five STS trials from a chair with the seat height adjusted to the length of their lower leg at a self-selected motion speed. Kinematic data were collected using a three-dimensional motion analysis system. We performed the UCM analysis to assess the effects of joint angle variance (elemental variable) to stabilize the horizontal and vertical movement of COM (performance variable) and calculated the joint angle variance that does not affect COM (V_UCM), the variance that affects COM (V_ORT), and the synergy index (ΔV).

RESULTS

ΔV values in the horizontal direction were higher in the older adults than in the younger adults, but ΔV values in the vertical direction were lower in the older adults than in the younger adults.

CONCLUSION

Older adults require increasing levels of stabilization of horizontal movement of COM after buttocks-off in the STS maneuver. As a result, variance in the joint angle of the lower extremities indicated no kinematic synergy for stabilizing the vertical movement of COM.

Appropriate seating for medical patients: an audit

OBJECTIVE

To determine the number and types of chairs available for patient use; to establish minimum criteria of appropriate chairs; and to assess the suitability of available chairs to seat patients admitted to medical wards.

METHODS

Audit of chairs available in medical wards in a tertiary referral public hospital was conducted. All chairs relevant to patient use were photographed and counted. An expert panel determined minimum criteria of appropriate seating for older patients from functional, occupational health and safety, ergonomic, infection control and usability viewpoints. The number of chairs meeting the minimum criteria level was recorded and was expressed as a percentage of the number of required chairs (hospitalised patients able to be sat out of bed).

RESULTS

A total of 270 chairs of 36 different types were identified. The majority of chairs, 231 (85%), did not meet the minimum criteria. Thirty-nine chairs met the minimum criteria for patients to sit in with 113 (66%) patients unable to sit out of bed.

CONCLUSION

This study identified that there were insufficient appropriate chairs available for patients to sit out of bed in this facility. This has potential implications for functional ability of the patients, particularly for the older person.

An in situ study of the habits of users that affect office chair design and testing

OBJECTIVE

The purpose of this study was to perform an in situ assessment of office seating habits that influence chair testing and design.

BACKGROUND

Many chair testing parameters were derived decades ago when the average weight of people within the United States was dramatically lower and the office work tasks less computer based.

METHOD

For the study, 51 participants were randomly selected from Brazos Valley, Texas, businesses to participate in 8-hr assessments of office seating habits. Overall results were compared with current chair testing and design assumptions. Data were collected through written survey and through data logging of seat and back contact pressure and duration with the use of the X-SENSOR pressure mapping device and software. Additionally, I day per participant of caster roll distance was recorded with the use of a caster mounted digital encoder. Participants were grouped by body mass index (BMI) and weight (BMI <35 and weight < 102 kg or BMI >35 and weight >102 kg).

RESULTS

It was determined that a significant difference did exist between the groups in mean seat time per shift (p < .001), back cycles per shift (p < .002), seat cycles per shift (p < .01), and caster distance rolled per shift (p < .001).

CONCLUSION

Several key parameters and assumptions of current chair test methods and design specifications may no longer be valid for the upper quartile of weight range of the current U.S. population.

APPLICATION

The data collected in this study will enable engineers to determine whether revision of design standards for testing office seating for both normal weight and extremely obese workers is indicated.

Evaluation of sit-to-stand motion using a pressure distribution measurement system--effect of differences in seat hardness on sit-to-stand motion

PURPOSE

This study examined differences between standing from an ordinary seat and standing from a low-repulsion mat using a pressure distribution measurement system (BIG-MAT) and identified parameters to determine sit-to-stand (STS) motion difficulty.

METHOD

Ten healthy male volunteers (aged 30-38 years) participated. During STS motion from an ordinary seat and from a low-repulsion urethane mat, plantar surface pressure changes of both feet and the centre of pressure (COP) trajectory were recorded for 7  s. This series of tests was performed four times in each subject. Left and right pressure changes and COP changes were evaluated. Differences in the measurements between the low-repulsion mat and the ordinary seat were compared using the paired t-test.

RESULTS

COP changes were similar to those previously reported. Time from hindfoot peak to forefoot peak was significantly shorter with the ordinary chair than with the mat (p < 0.05). Percent change in forefoot pressure at forefoot peak and hindfoot peak (p < 0.01) and percent change in forefoot pressure at forefoot peak and stabilisation (p < 0.05) were significantly different.

CONCLUSIONS

Time from hindfoot peak to forefoot peak and percent change in forefoot pressure at forefoot peak and hindfoot peak were the best indicators of STS motion difficulty.

Comfort and its measurement--a literature review

PURPOSE

This review aims to identify measures suitable for evaluation of physical comfort in a range of clinical settings or specialised areas.

METHOD

A review of literature included articles that evaluated an intervention, position, equipment or surface for comfort or discomfort. Electronic databases, hand searches and internet sources were used.

RESULTS

In addition to several theoretical papers on comfort, 29 studies were identified that used 'comfort' or 'discomfort' as outcomes. There was a lack of consistency in measurement of comfort and researchers used a wide range of different scales and tools. Objective and subjective measures are described. The impact of symptoms, environmental variables and emotional factors was generally not considered. Two instruments evaluating subjective comfort or discomfort were identified that have been carefully developed and psychometrically tested. Both have potential for use in clinical practice and research - one developed for wheelchair seating and one for wearable computers. Suggestions for clinical evaluation of comfort based on the research and theoretical papers regarding measurement scales are made.

CONCLUSION

Further work on development and validation of comfort assessment tools for other applications is needed.

RESNA position on the application of seat-elevating devices for wheelchair users

This document, approved by the Rehabilitation Engineering & Assistive Technology Society of North America (RESNA) Board of Directors in September 2005, shares typical clinical applications and provides evidence from the literature supporting the use of seat-elevating devices for wheelchair

Tilted seat position for non-ambulant individuals with neurological and neuromuscular impairment: a systematic review

Objective: To determine the effects of tilt-in-space seating on outcomes for people with neurological or neuromuscular impairment who cannot walk.

Data sources: Search through electronic databases (MEDLINE, Embase, CINAHL, AMED). Discussions with researchers who are active in field.

Review methods: Selection criteria included interventional studies that investigated the effects of seat tilt on outcome or observational studies that identified outcomes for those who had used tilt-in-space seating in populations with neurological or neuromuscular impairments. Two reviewers independently selected trials for inclusion, assessed quality and extracted data.

Results: Nineteen studies were identified which fulfilled the selection criteria. Seventeen of these were essentially before–after studies investigating the immediate effects of tilting the seating. All studies looked at populations with neurological impairment, and most were on children with cerebral palsy (n = 8) or adults with spinal cord injury (n = 8).

Reviewer's conclusion: Posterior tilt can reduce pressures at the interface under the pelvis.

Bed and Toilet Height as Potential Environmental Risk Factors

Seat height that is too high (> 120% of lower leg length [LLL]) or too low (< 80% of LLL) can impede safe transfer and result in falls. This study examines the difference between LLL of frail nursing home residents and the height of their toilets and beds in the lowest position, compares the patient or environmental characteristics of those able to transfer from the bed or toilet to those who cannot, and determines the relationship of patient or environmental characteristics to bed-related falls. A retrospective observational design using secondary data from 263 nursing home residents finds that bed height of three fourths of participants was greater than 140% of LLL, whereas toilet height of more than half was 100% to 120% of LLL. Increased fall risk is associated with increased age, shorter length of stay, normal lower extremity range of motion, less cognitive impairment, more behavioral symptoms, and no complaints of pain during exam.

Instant of chair-rise lift-off can be predicted by foot–floor reaction forces

OBJECTIVE

To develop a predictive model of the lift-off event during chair rise in healthy subjects, using foot-floor reaction forces.

BACKGROUND

An important event during chair rise is lift-off from the seat: the transition from the inherently stable three-point contact to the unstable two-point contact. There is no consistent or generally agreed upon method for estimating the time of lift-off when an instrumented seat is unavailable.

METHODS

Twenty healthy volunteers were divided into a testing set and training set. Each subject performed repeated chair rise trials at different speeds. Seat-floor and foot-floor forces, recorded with two force platforms, were used to develop a model of the lift-off event.

RESULTS

The magnitude of the vertical foot-floor reaction at lift-off (F0VF) was linearly related (R2 = 0.71, P < 0.001) to the peak vertical foot-floor reaction force (FMVF). A linear model was developed for the training group, which enabled prediction of lift-off time for the testing group with an absolute average error of 6 ms (about 1 data frame at 150 Hz). The linear model derived for the entire sample was: F0VF = 28.14 + FMVF * (0.6434).

CONCLUSIONS

The lift-off event for healthy subjects performing chair rise can be accurately predicted from foot-floor reaction forces, without requiring an instrumented seat.

Relationship between knee extension force and stand-up performance in community-dwelling elderly women

OBJECTIVE

To describe the relationship between knee extension force and stand-up performance.

DESIGN

Prospective, cross-sectional, descriptive, and correlational.

SETTING

Community.

PARTICIPANTS

Fifty-five community-dwelling women 60 or more years old.

INTERVENTIONS

Information pertaining to stand-up performance was gathered via structured questions. The time to complete 1 sit-to-stand from a bench of known height (16in) was obtained in conjunction with subjects' ratings of perceived exertion (RPEs) relative to the task. Bilateral lower extremity knee extension strength was measured with a hand-held dynamometer and normalized against body weight.

MAIN OUTCOME MEASURES

Total knee extension forces (raw and body-weight normalized values) generated by each subject were correlated with 3 measures of stand-up performance.

RESULTS

Low to moderate correlations (r = -.323 to -.526) were found between knee extension forces and the stand-up performance measures of bench stand time and stand-up difficulties. Normalized knee extension force had a higher correlation than raw knee extension force with stand-up difficulties and RPE. Correlations were higher when the curvilinear nature of the relationship was taken into account. The highest correlation was between normalized knee extension force and the RPE associated with the bench stand task (r = -.767).

CONCLUSION

Knee extension force offers an important but incomplete explanation of stand-up performance from low surfaces by elderly women. Interventions leading to increased knee extension force may improve stand-up performance.

Task-specific resistance training to improve the ability of activities of daily living-impaired older adults to rise from a bed and from a chair

OBJECTIVES

To determine the effect of a 12-week intervention to improve the ability of disabled older adults to rise from a bed and from a chair.

DESIGN

Subjects were randomly allocated to either a 12-week task-specific resistance-training intervention (training in bed- and chair-rise subtasks, such as sliding forward to the edge of a chair with the addition of weights) or a control flexibility intervention.

SETTING

Seven congregate housing facilities.

PARTICIPANTS

Congregate housing residents age 65 and older (n = 161, mean age 82) who reported requiring assistance (such as from a person, equipment, or device) in performing at least one of the following mobility-related activities of daily living: transferring, walking, bathing, and toileting.

MEASUREMENTS

At baseline, 6 weeks, and 12 weeks, subjects performed a series of bed- and chair-rise tasks where the rise task demand varied according to height of the head of the bed, chair seat height, and use of hands. Outcomes were able or unable to rise and, if able, the time taken to rise. Logistic regression for repeated measures was used to test for differences between tasks in the ability to rise. Following log transformation of rise time, a linear effects model was used to compare rise time between tasks.

RESULTS

Regarding the maximum total number of bed- and chair-rise tasks that could be successfully completed, a significant training effect was seen at 12 weeks (P = .03); the training effect decreased as the total number of tasks increased. No statistically significant training effects were noted for rise ability according to individual tasks. Bed- and chair-rise time showed a significant training effect for each rise task, with analytic models suggesting a range of approximately 11% to 20% rise-time (up to 1.5 seconds) improvement in the training group over controls. Training effects were also noted in musculoskeletal capacities, particularly in trunk range of motion, strength, and balance.

CONCLUSIONS

Task-specific resistance training increased the overall ability and decreased the rise time required to perform a series of bed- and chair-rise tasks. The actual rise-time improvement was clinically small but may be useful over the long term. Future studies might consider adapting this exercise program and the focus on trunk function to a frailer cohort, such as in rehabilitation settings. In these settings, the less challenging rise tasks (such as rising from an elevated chair) and the ability to perform intermediate tasks (such as hip bridging) may become important intermediate rehabilitation goals.

The seating dilemma in aged care

Choosing the most appropriate easy chair for elderly clients is often difficult. The demands that need to be fulfilled by the chair chosen need to be identified and considered in order of priority. Benefits of good seating are identified, as are consequences of poor seating. Some guidelines are provided for choosing specific chair characteristics. There is discussion of the thought provoking points raised.

Effects of functional ability and training on chair-rise biomechanics in older adults

BACKGROUND

Difficulty in rising from a chair is common in older adults and may be assessed by examining the biomechanics of the rise. The purposes of this study were (i) to analyze the biomechanics of rise performance during chair-rise tasks with varying task demand in older adults with varying rise ability and (ii) to determine whether a strength-training program might improve chair-rise success and alter chair-rise biomechanics, particularly under situations of increased task demand.

METHODS

A training group (n = 16; mean age, 82 years) completed a 12-week strength-training regimen while a control group (n = 14; mean age, 84 years) participated in a seated flexibility program. Outcomes included the ability to complete seven chair-rise tasks, and, if the chair-rise tasks were successful, the biomechanics of these rises. Chair-rise task demand was increased by lowering the seat height, restricting the use of hands, increasing rise speed, and limiting foot support.

RESULTS

At baseline, increased chair-rise task demand generally required increased task completion time, increased anterior center of pressure (COP) placement, increased momentum, increased hip flexion, and increased hip and knee torque output. Those unable to rise at 100% knee height without the use of their hands (task NH-100), compared with those able to rise during task NH-100, followed this pattern in requiring increased time, more anterior placement of the COP, and increased hip flexion to rise in the least demanding tasks allowing the use of hands. However, the unable subjects generated less momentum and knee torque in these tasks. At 12 weeks, and compared with baseline and controls, the training group demonstrated changes in chair-rise biomechanics but no significant changes in rise success. The training subjects, as compared with the controls, maintained a more posterior COP, increased their vertical and horizontal momentum, maintained their knees in greater extension, and maintained their knee-torque output.

CONCLUSIONS

These data demonstrate that subtle yet significant changes can be demonstrated in chair-rise performance as a result of a controlled resistance-training program. These biomechanical changes may represent a shift away from impairment in chair-rise ability, and, although the changes are small, they represent how training may reduce rise difficulty.

Biomechanical analysis of effects of foot placement with varying chair height on the motion of standing up

Individual experience reveals that posterior foot placement enables one to stand up easily from a chair. However, the way in which foot placement affects this motion has not been investigated in detail. This study was performed to examine the effects of foot placement in the initial stage of the dynamics of standing up from a chair. Subjects wearing light-emitting diode markers and surface electrodes stood up from a chair over force plates, and ground reaction force, joint angle, and muscle activity were measured. The motions required to stand up from chairs 30, 40, or 50 cm in height were analyzed with anterior, vertical, and posterior foot placement. With anterior foot placement, the forward-acceleration components of the ground reaction force were recorded with simultaneous and long-sustained activity of the muscles in order to shift the center of gravity of the body forward even more after lift-off. Our findings indicate that the distance between the center of gravity and the point of application of ground reaction force at lift-off are critical factors in the standing-up motion, and that chairs should be of adequate height as well as having sufficient space under the seat to permit the backward movement of the lower legs.

Chair and bed rise performance in ADL-impaired congregate housing residents

OBJECTIVES

To examine the ability of activity of daily living (ADL)-impaired older adults to successfully rise, and, when successful, the time taken to rise, from a bed and chair under varying rise task demands.

SETTING

Seven congregate housing facilities

SUBJECTS

Congregate housing residents (n = 116, mean age 82) who admitted to requiring assistance (such as from a person, equipment, or device) in performing at least one of the following mobility-related ADLs: transferring, walking, bathing, and toileting.

METHODS

Subjects performed a series of bed and chair rise tasks where the rise task demand varied according to the head of bed (HOB) height, chair seat height, and use of hands. Bed rise tasks included supine to sit-to-edge, sit up in bed with hand use, and sit up in bed without hands, all performed from a bed where the HOB was adjusted to 0, 30, and 45 degrees elevations; roll to side-lying then rise (HOB 0 degrees); and supine to stand (HOB 0 degrees). Chair seat heights were adjusted according to the percent of the distance between the floor and the knee (% FK), and included rises (1) with hands and then without hands at 140, 120, 100, and 80% FK; (2) from a reclining (105 degrees at chair back) and tilting (seat tilted 10 degrees posteriorly) chair (100% FK); and (3) from a 80% FK seat height with a 4-inch cushion added, with and then without hands. Logistic regression for repeated measures was used to test for differences between tasks in the ability to rise. After log transformation of rise time, a linear effects model was used to compare rise time between tasks.

RESULTS

The median total number of tasks successfully completed was 18 (range, 3-21). Nearly all subjects were able to rise from positions where the starting surface was elevated as long as hand use was unlimited. With the HOB at 30 or 45 degrees essentially all subjects could complete supine to sit-to-edge and sit up with hands. Essentially all subjects could rise from a seat height at 140, 120, and 100% FK as long as hand use was allowed. A small group (8-10%) of subjects was dependent upon hand use to perform the least challenging tasks, such as 140% FK without hands chair rise and 45 degrees sit up without hands. This dependency upon hand use increased significantly as the demand of the task increased, that is, as the HOB or seat height was lowered. Approximately three-quarters of the sample could not rise from a flat (0 degrees HOB elevation) bed or low (80% FK) chair when hand use was not allowed. Similar trends were seen in rise performance time, that is, performance times tended to increase as the HOB or chair seat elevation declined and as hand use was limited. Total self-reported ADL disability, compared to the single ADL transferring item, was a stronger predictor of rise ability and timed rise performance, particularly for chair rise tasks.

CONCLUSIONS

Lowering HOB height and seat height increased bed and chair rise task difficulty, particularly when hand use was restricted. Restricting hand use in low HOB height or lowered seat height conditions may help to identify older adults with declining rise ability. Yet, many of those who could not rise under "without hands" conditions could rise under "with hands" conditions, suggesting that dependency on hand use may be a marker of progressive rise impairment but may not predict day-to-day natural milieu rise performance. Intertask differences in performance time may be statistically significant but are clinically small. Given the relationship between self-reported ADL disability and rise performance, impaired rise performance may be considered a marker for ADL disability. These bed and chair rise tasks can serve as outcomes for an intervention to improve bed and chair rise ability and might also be used in future studies to quantify improvements or declines in function over time, to refine physical therapy protocols, and to examine the effect of bed and chair design modifications on bed and chai

Individualized interventions to prevent bed-related falls and reduce siderail use

Five categories of problems that often result in siderail use: memory disorder, impaired mobility, injury risk, nocturia/incontinence, and sleep disturbance. As nursing homes work toward meeting the Health Care Financing Administration's mandate to examine siderail use, administrators and staff need to implement interventions that support safety and individualize care for residents. While no one intervention represents a singular solution to siderail use, a range of interventions, tailored to individual needs, exist. This article describes the process of selecting individualized interventions to reduce bed-related falls.

Sitting posture and prevention of pressure ulcers

The aim of this study was to gain insight about the influence of body posture on the pressure at the seat surface and to establish to what extent different seat cushions designed for incontinent patients reduce maximum pressures. Pressures were measured for 56 healthy volunteers in eight postures using four cushions. The posture in which the lowest maximum pressure was measured was the sitting-back posture with the lower legs on a rest. If the seat could not be tilted back, the maximum pressure in the upright sitting posture with the feet on the ground was significantly lower than sitting upright with the legs supported on a rest. Sliding down and slouching caused the highest maximum pressure. Regular checking of the posture and using positioning cushions should form part of any pressure-ulcer prevention protocol. The four selected cushions each have different pressure-reducing effects. A thick air cushion (Repose) has the lowest maximum pressure and is significantly better than the other cushions at reducing the high pressure when slouching or sliding down.

Geriatric rehabilitation: state of the art

OBJECTIVES

To provide a clinically useful conceptual framework for the evaluation and treatment of disability in older persons, to review the rehabilitation of common conditions affecting function in older persons, and to discuss the effects of the ongoing changes in the healthcare system on geriatric rehabilitation.

METHODS

MedLine search and review of relevant texts for information on (1) geriatric disability and its treatment, (2) recent high quality research, guidelines, and review articles relevant to the rehabilitation of conditions commonly causing geriatric disability, (3) effects of recent changes in the healthcare system on geriatric rehabilitation.

RESULTS

Several pertinent models for geriatric disability were identified. These are explicated, along with information on the epidemiology of geriatric disability and its causes and relevant clinical applications. Rehabilitation is reviewed for musculoskeletal disorders, stroke and peripheral vascular disease, amputation, cardiopulmonary disorders, hip fracture, and deconditioning. Changes in the healthcare system appear to be affecting geriatric rehabilitation, especially the advent of managed care; relevant articles and opinions are reviewed, along with strategies to accommodate these changes.

CONCLUSIONS

Our understanding of the causes of disability in the older population has improved significantly over the last decade. There has also been noteworthy progress in our knowledge about the effects of selected rehabilitation interventions, especially exercise-related interventions. However, the cost-effectiveness of many rehabilitative interventions remains unclear, particularly for differing patient groups across the continuum of care. More research will be needed to evaluate the effects of managed care on rehabilitation outcomes in older persons.

An analysis of human comfort when entering and exiting the rear seat of an automobile

This paper describes a study of human motion and human comfort when entering and exiting the rear seat of an automobile. A simulator was used to test several possible door frame configurations, and various positions of the front and rear seats. Thirty-six human subjects were asked to enter and exit the simulator five times for each configuration and to answer a subjective questionnaire. The motion performed by each test subject was recorded by means of a VHS recorder and an ELITE motion measurement system. A statistical analysis was performed on the data from the questionnaires and comfort rankings were produced for the various configurations. The most influential design parameters were identified and iso-comfort surfaces were defined and fitted which provided a simple means of quantifying the effect of one of the main parameters.