Purpose of the Work. This work reports
prosthesis-related issues from a diverse group of persons
with amputation who wear lower-limb prostheses.
Subjects/Procedures. Persons with lower-limb
amputations were identified from computerized rosters at the
VAMC Seattle, Washington. One hundred fourteen persons
participated and completed a prosthesis evaluation
questionnaire. They graded how important various
characteristics and qualities of their prostheses were to
them. Results. Four themes of interest were
identified from responses to open-ended questions about
living with a prosthesis: fit of the socket, mechanical
function of the prosthesis, other qualities of the
prosthesis, and adaptation of the person to life with a
prosthesis. Relevance to the Veterans Population.
Knowledge of veterans' opinions about the quality of their
lives since their amputations will help researchers adjust
certain aspects of the fit of a prosthesis to a residual
limb to eliminate unnecessary suffering.
Purpose of the Work. Failure of prosthetic
components during kneeling has been reported. This study
provides the first objective data on the loads generated
during kneeling activities. Subjects and Procedures.
The data were acquired by conducting 162 tests on four male
amputees wearing prostheses incorporating load measuring
transducers and kneeling against two force platforms.
Results. The critical areas in a prosthesis, during
kneeling, were found to be at the knee and shank. The loads
determined were much higher than these developed during
level walking. Relevance to Veteran Population. The
data obtained were submitted to the International Standards
Organisation (ISO) and are now used for guidance in the
determination of the test configuration and load values for
the standard for structural testing of trans-femoral
prostheses. The information given in this paper should be
useful to designers in ensuring the production of robust,
lightweight prostheses.
Stephan Solomonidis, BSc, FIMechE
Purpose of the Work. Joint power produced during
walking is a good index of age related mobility decline. We
investigated joint power sensitivity to impairments and
aging. Subjects/Procedures. Motion analysis was
performed on healthy young, healthy elderly, and disabled
elderly subjects while walking. Traditional walking
performance measures (such as walking velocity) and less
conventional mechanical power produced at the ankle, knee
and hip were calculated from the movement data.
Results. Differences in walking velocity were
observed between young and elder subjects, but not between
healthy elders and disabled elders. There were large
differences in the amount of ankle power generated at
"push off" of stance phase between the healthy
elderly and disabled elderly, that were not present between
healthy young and healthy elderly. Relevance to the
Veteran Population. Traditional walking performance
measures may not be sensitive enough to indicate the onset
and magnitude of disabling conditions in elders. Decreased
ability to generate ankle power during walking, however, may
be a better way to discriminate between healthy elders and
those at risk for disablement.
Chris A. McGibbon, PhD
Purpose of the Work. Although cycle exercise
training has been shown to improve aerobic endurance
individuals with multiple sclerosis (MS), the carry-over
effects to the more functional activity of walking have not
been investigated. The goal of this study was to determine
the effects of a six month cycling exercise program on the
walking ability of individuals with MS. Subjects.
Nineteen patients (14 female, 5 male) with MS of differing
disability participated in this study. Procedures.
Gait analysis was performed before and after the exercise
program. The exercise program consisted of cycle exercise
three times a week for 30 minutes. Results. Walking
speed decreased after training. Other walking
characteristics were minimally effected by the training
program. Relevance to Veteran Population. It appears
that a long term cycling program may be most beneficial for
increasing aerobic endurance, and less beneficial to
improving gait in individuals with MS.
Mary Rodgers, PhD
Purpose of the Work. This article describes the
effect of increasing temperature on the relationship between
skin blood flow and increasing surface pressure, and how
these parameters impact skin deformation.
Subjects/Procedures. Skin surface pressure was
applied over the hips of Fuzzy Rats by a computer-controlled
plunger with skin deformation measured by an electronic
sensor. Laser light was used to measure the blood flow in
the skin while temperature was mildly increased at the
surface using an attached heating block. The experimental
protocols allowed us to study changes in skin blood flow and
deformation of heated and unheated tissue during exposure to
surface pressure. Results. It was found that for
surface pressures below 18 mmHg, increasing skin temperature
significantly increased skin perfusion and tissue stiffness.
Relevance to the Veteran Population. This study
implies that a mild increase in temperature resulting in a
stiffening of the tissue has the potential to reduce both
skin breakdown and pressure ulcer formation. Pressure ulcers
continue to have a negative impact on important veteran
patient populations including the spinal cord injured and
the aged.
Suryachandra Patel, MD, PhD
Purpose of the Work. This study compared
transcutaneous oxygen tension (TcpO2), a measure
of local oxygen supply to the tissue, in subjects with
paraplegia and pressure ulcers (PU-PARA), those with
paraplegia and no pressure ulcer (NPU-PARA) and ambulatory
subjects (control). Subjects/Procedures.
TcpO2 was measured at rest in the supine position
using a surface electrode monitoring system, recorded at one
minute intervals for five minutes. Results. Mean
TcpO2 was significantly lower in the PU-PARA than
the NPU-PARA and control groups (23.53±1.83 vs.
58.93±2.53 and 79.70±6.77 mmHg, respectively).
The NPU-PARA group also demonstrated significantly lower
TcpO2 than controls. Relevance to the Veteran
Population. TcpO2 may be an effective method
to identify individuals who are susceptible to develop
pressure ulcers. The further attenuation of TcpO2
observed in the pressure ulcer group may be a useful tool to
help predict whether ulcers will heal with local care or
whether additional treatment is required.
Mon Hsia Liu, BS
Purpose of the Work. This article describes
parameters regarding pedaling effectiveness and knee joint
loading during functional electrical stimulation induced
cycling. Subjects/Procedures. Specialized pedals,
which measure forces during bicycling, were used while
spinal cord injured (SCI) subjects participated in a
functional electrical stimulation induced cycling program.
Pedal forces were used to calculate knee joint loading
parameters. Results. Pedaling effectiveness was
severely compromised, knee joint parameters suggest
excessive loading, and the overall analysis revealed an
energetically unfavorable knee stabilizing mechanism within
the bicycle configuration used. Relevance to the Veteran
Population. These findings suggest that the knee joint
loading during this exercise modality may be large enough to
produce a "trivial fracture" in the compromised
lower limbs of individuals with SCI. Future studies
involving changes in bicycle configuration and knee joint
loading are necessary to maximize the cardiopulmonary and
musculoskeletal benefits of functional electrical
stimulation induced cycling in the SCI population.
John C. Franco MD, MS
Purpose of the Work. This article describes the
design and the development of a robotized workstation
intended for tetraplegic users with the goal of improving
their autonomy and thus their quality of life.
Subjects/Procedures. After a need analysis performed
with medical doctors, researchers and tetraplegic users
realized and evaluated several prototypes of the workstation
Master in French rehabilitation centers. Results.
About one hundred individuals have successfully tested the
workstation over a period of 2 years. The configured
operator interface gives access, in real time, to four
functions the can be combined: a robotic arm with two
running modes: automatic and /or direct, an environment
control system, and office software. Relevance to the
Veteran Population. Such a system offers several
advantages to persons without motricity of upper limbs,
mainly fuctional tetraplegics. It is potentially an
important tool for domestic and vocational applications,
promoting the rehabilitation of tetraplegics in society.
Bernard Lesigne, PhD
Purpose of the Work. This study describes an algorithm that
is used to modify speech signals for hearing impaired
listeners. Subjects/Procedures. The proposed method makes
the use of multiresolutional analysis in association with
speech modification algorithms. The algorithm modifies the
wavelet coefficients of the speech in order to obtain a more
intelligible speech signal. The performance of the algorithm
has been evaluated using both normal and hearing impaired
subjects. Results. Listening tests showed that the proposed
algorithm increases the quality and intelligibility of the
modified speech over the well-known modification algorithms.
The preliminary test results also suggest that
multiresolutional modification algorithm can be used to
overcome the deterioration of peripheral ability. Relevance
to the Veteran Population. The algorithm can be used in the
implementation of digital hearing instruments regarded as
having a function complementary to that of conventional
hearing aids.
Osman Eroul, MSc,
PhD
Purpose of the Work. This paper describes new on-line
parameters for analysis of dynamic foot pressures in
neuropathic feet of Hansen's disease subjects.
Subjects/Procedures. The foot pressures during walking are
measured by using a long optical pedobarograph and a
specially developed on-line image processing software. Two
new on-line parameters are obtained by considering peak foot
pressures, body weight, walking velocity, and duration of 50%
of peak pressure. Results. The mean values of the new foot
pressure parameters, for various classes of Hansenīs disease
subjects, are found to be significantly different from those
of the normal subjects and on-line calculation of these
helps in quickly assessing the areas of the feet subjected
to high and long duration loading. Relevance to the Veteran
Population. The foot areas, with no plantar sensation and
both the parameters being high, are at a great risk of
ulceration and this information can aid the clinician to
prescribe suitable footwear to prevent plantar ulcers at an
early stage.
Mahesh M Bhatia, MS
Purpose of the Work. This paper describes three-dimensional
foot modeling and analysis of stresses in normal and early
stage Hansen's disease with muscle paralysis that could
possibly help in understanding disintegration of tarsal
bones in Hansen's disease. Subjects/Procedures. Stress
analysis is carried out on three-dimensional foot models of
normal and Hansen's disease subjects by finite element
technique simulating quasi-static walking phases of
heel-strike, mid-stance, and push-off. Results. The analysis
shows that the highest stresses occur during push-off phase
in certain areas and joints of the foot bones of a normal
subject and these stresses increase by 25-50% in early stage
Hansen's disease with muscle paralysis. Relevance to the
Veteran Population. The high stress concentration areas in
the foot bones are of great importance since it is found
from clinical reports that in certain Hansen's disease
subjects, these areas of the bones get disintegrated if
subjected to osteoporosis due to decreased mechanical
strength of the bone caused by Hansen's disease.
Shanti Jacob, PhD
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Last Updated Tuesday, May 29, 2007 8:26 AM