The effect that energy storage and return feet have on the propulsion of the body: a pilot study.

A variety of energy storage and return prosthetic feet are currently available for use within lower limb prostheses. Designs claim to provide a beneficial energy return during push-off, but the extent to which this occurs remains disputed. Techniques currently used to measure energy storage, dissipation and return within the structure of the prosthetic foot are debatable, with limited evidence to support substantial elastic energy storage and return from existing designs. The aim of this study was to evaluate the performance of energy storage and return foot designs through considering the ankle power during push-off and the effect on body centre of mass propulsion. To achieve this aim, the gait patterns of six trans-tibial prosthetic users wearing different designs of energy storage and return feet were analysed while ascending a ramp. Three examples of energy storage and return feet (suitable for moderate activity) were selected and randomly evaluated: the Blatchford's Epirus, Össur Assure and College Park Tribute feet. The power at the anatomical and mechanical ankle joints was integrated to evaluate the work done over the gait cycle. The direction of the inertial force, and therefore propulsion of the body centre of mass, was used to indicate the effect of the energy return by the energy storage and return feet. Results indicate that although energy storage and return feet may provide energy return, the work done around the prosthetic ankle indicates net power absorption. Therefore, the prosthetic limb is unable to contribute to the body centre of mass propulsion to the same extent as the biological limb.

The relationship between parameters of static and dynamic stability tests.

BACKGROUND: Stability is often described to be static (quiet standing) and dynamic (maintaining a stable position while undertake a prescribed movement). Many researchers have used only static tests to evaluate the stability of normal and handicapped subjects. However, it is important to evaluate the stability of subjects while undertaking various tasks (dynamic stability). It is not currently clear whether static balance can predict dynamic balance or not. Therefore, the aim of this research was to investigate the relationship between parameters of static and dynamic stability tests. METHODS: The current clinical trial study was carried out in the Bioengineering Unit of Strathclyde University during 2008 and 2009. The normal subjects with no history of musculoskeletal disorders from staff and students of the Unit were selected in this study. Twenty-five normal subjects were recruited to participate in this research project. They were asked to stand on a force plate in quiet standing and while undertaking various hand tasks. The functional stability of the subjects was measured while transverse and vertical reaching tasks were undertaken. The correlation between various parameters of stability in quiet standing and functional hand tasks was evaluated using Pearson correlation. RESULTS: There was no significant correlation between static and dynamic stability parameters. The Pearson correlation coefficients for all parameters regarding the static and dynamic tests were less than 0.46. CONCLUSIONS: As there was no correlation between stability parameters in quiet standing and while performing various hand tasks, it is not practical to discuss ability of the subjects to control their balance while undertaking various hand tasks based on static balance ability.

Performance of insole in reducing plantar pressure on diabetic patients in the early stages of the disease.

It has been well documented that subjects with peripheral neuropathy resulting from diabetes mellitus are at high risk of developing foot ulceration. Decreased sensation, in combination with high underfoot pressures, have been identified as prime etiology factors in the cause of plantar naturopathic ulceration [1]. This study presents the effect of four orthotic treatment techniques in reducing metatarsal head, heel and toes pressure during walking. A pressure measurement study was carried out on a diabetic patients group wearing four insoles, including the insole designed by the computer model proposed in this project. The aim of this study was to evaluate the effect on plantar pressure in diverse insoles prescribed and manufactured with various techniques on a random group of patients with diabetes mellitus in the early stages of the disease. Four types of insoles were designed and manufactured by methods available in the market; the computer model proposed on this project was used in order to design and manufacture the insole. The results show that every patient requires an individual assessment and often a personalized insole.

The characterisation of gait patterns of people with multiple sclerosis.

BACKGROUND: There are relatively few reports describing gait patterns in multiple sclerosis (MS) and most are confined to the analysis of temporal distance parameters with some assessment of joint range of motion. The aim of this study was to perform a biomechanical characterisation of gait patterns among people with MS across a wide range of severity of ambulatory impairment. METHODS: Sixteen patients with MS were recruited for this study. Initially, the spasticity of lower limb muscle groups was measured and ambulatory ability was graded. Patients were then placed in two groups based on the level of severity of ambulatory ability. Kinematic, kinetic and EMG gait data from both MS groups were then compared to a control group of 10 healthy subjects. RESULTS: Patients with MS in both groups were found to walk with reduced gait speed, reduced maximum hip and knee extension, ankle plantarflexion angle and propulsive force compared to the control group. In general, the same gait impairments were found in both MS groups compared to the control group, and were greater for the more severely affected MS patient group. INTERPRETATION: This study highlights typical gait patterns of people with MS and provides an indication of common pathways in the degeneration of ambulatory ability as a consequence of disease progression. This information should enable improved clinical treatment of ambulation, as well as the prescription, or even design, of appropriate assistive devices.

An investigation of teaching staff members' and parents' views on the current state of adaptive seating technology and provision.

PURPOSE: It is recognized that for children with poor postural control, a comfortable adaptive seating system which provides them with the support needed to maintain a sitting position can be essential for raising their overall level of well being. The purpose of this study was to investigate the views of teaching staff members at special needs schools and of the parents of children who attended these schools on the provision and current technology of seating systems. METHOD: Two similar questionnaires intended to elicit the views of teaching staff and the parents of children attending these schools were designed and distributed to these groups. RESULTS: Dissatisfaction exists with reliability of these systems and the time it takes for replacement systems to be issued. The perceived importance of adaptive seating role in the user being accepted by peers was found to be statistically different between the two groups. Time spent per day transferring the child to and from seating systems was found to be greater than 1 h for both groups. CONCLUSION: Scope remains for improvements to be made in adaptive seating provision and technology. Although mainly descriptive, these results could be of use when developing newer systems and improving services.

Ambulatory rehabilitation in multiple sclerosis.

Multiple sclerosis (MS) is an autoimmunogenic disease involving demyelination within the central nervous system. Many of the typical impairments associated with MS can affect gait patterns. With walking ability being one of the most decisive factors when assessing quality of life and independent living, this review focuses on matters, which are considered of significance for maintaining and supporting ambulation. This article is an attempt to describe current research and available interventions that the caring healthcare professional can avail of and to review the present trends in research to further these available options. Evidence-based rehabilitation techniques are of interest in the care of patients with MS, given the various existing modalities of treatment. In this review, we summarise the primary factors affecting ambulation and highlight available treatment methods. We review studies that have attempted to characterise gait deficits within this patient population. Finally, as ambulatory rehabilitation requires multidisciplinary interventions, we examine approaches, which may serve to support and maintain ambulation within this patient group for as long as possible.

The potential for actigraphy to be used as an indicator of sitting discomfort.

OBJECTIVE: A novel technique that uses actigraphy, the study of activity involving the use of body-mounted accelerometers, to detect the discomfort-related movements of a sitting individual has been proposed as a potential indicator of sitting discomfort, and the purpose of this study was to test its validity. BACKGROUND: Objective measurement of sitting discomfort has always been challenging for researchers. Electromyographic measurements, pressure mapping, and a wide range of other techniques have all been investigated with limited success. METHOD: The activity monitor's ability to detect and measure seated movement was assessed, and 12 participants were tested on four different chairs (100-min sessions for each). RESULTS: The activity monitor was able to detect participants' sitting movements (Pearson coefficients > 0.9). The chairs were shown to have significantly different subjective discomfort ratings, all of which increased over time. The movements detected by the activity monitor also increased significantly with time, and the amount measured was greater in the chairs rated as most uncomfortable. Regression analysis indicated that the actigraphy data were able to account for 29.6% of the variation in perceived discomfort ratings. CONCLUSION: Actigraphy can reliably detect sitting movements and may be of use in measuring sitting discomfort. APPLICATION: Potential applications of this technique exist for seating research in the automotive industry, health care, and office and leisure chairs.

Ultrasound imaging in lower limb prosthetics.

The biomechanical interaction between the residual limb and the prosthetic socket determines the quality of fit of the socket in lower limb prosthetics. An understanding of this interaction and the development of quantitative measures to predict the quality of fit of the socket are important for optimal socket design. Finite-element modeling is used widely for biomechanical modeling of the limb/socket interaction and requires information on the internal and external geometry of the residual limb. Volumetric imaging methods such as X-ray computed tomography, magnetic resonance imaging, and ultrasound have been used to obtain residual limb shape information. Of these modalities, ultrasound has been introduced most recently and its development for visualization in prosthetics is the least mature. This paper reviews ultrasound image acquisition and processing methods as they have been applied in lower limb prosthetics.

Pressure distribution at the seating interface of custom-molded wheelchair seats: effect of various materials.

OBJECTIVE: To identify which of 4 materials has the most favorable pressure distribution when used in custom-molded seats (CMSs) to assist clinicians in providing appropriate seating for wheelchair-bound individuals who are prone to develop pressure ulcers. DESIGN: Repeated-interface pressure measurements for all materials, followed by statistical analysis. SETTING: The general community and referral centers. PARTICIPANTS: Seven subjects, 5 with cerebral palsy, 1 with Schilder's disease, and 1 with postmeningitis effects. All subjects were seated in a CMS and had spinal deformities. INTERVENTIONS: Viscoelastic polyurethane foams (Pudgee, Sunmate) and gels (Floam trade mark, Jay) were used as inserts in the CMSs. Evazote foam was used as a control material. MAIN OUTCOME MEASURES: Pressure readings were taken at the seat interface with pneumatic pressure sensors and the Talley Pressure Monitor. Peak pressure readings, mean pressure ratio, and peak pressure ratio for the different materials were compared. RESULTS: Foams, Sunmate in particular, produced lower peak-interface pressures and also showed better pressure distribution than did gels. CONCLUSION: Foams are the preferred insert material with CMSs when increased tissue breakdown risk is present.