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Speech tests as measures of outcome.

Speech tests comprise an important and integral part of any assessment of the effectiveness of intervention for hearing disability and handicap. Particularly when considering hearing aid services for adult listeners, careful consideration has to be given to the particular form and application of inferences drawn from speech identification procedures if erroneous conclusions are to be avoided. It is argued that four such components relate to the statistical properties and discriminatory leverage of speech identification procedures, the choice of presentation level and conditions in regard to the auditory environment experienced by hearing-impaired clients, the extent to which speech tests based on segmental intelligibility provide appropriate information in relationship to perceived disabilities and handicaps, and the ways in which speech identification procedures to evaluate the potential benefits of signal-processing schemes for hearing aids are dependent upon sufficient listening experiences. Data are drawn from the literature to illuminate these points in terms of application in clinical practice and clinical evaluation exercises, and also with regard to future research needs.

Adult↗

A new more powerful bone-anchored hearing aid: first results.

In a pilot study seven subjects were asked to use a new more powerful bone-anchored hearing aid, the BAHA cordelle, for 5 days. All seven had a moderate or severe sensorineural component in their hearing loss and had been using a BAHA superbass on a daily basis for more than 2 years. Free-field thresholds and speech recognition were measured with the BAHA superbass and with the BAHA cordelle. A questionnaire was also filled in to obtain subjective information about speech recognition with the BAHA superbass compared to the BAHA cordelle. Aided thresholds in the high frequency range with the BAHA cordelle were better than with the BAHA superbass. In six of the seven subjects there was significant improvement in the speech recognition score with the BAHA cordelle. These six subjects expressed preference for the BAHA cordelle.

Adult↗

The effect of water hydraulic permeability on the settling of a soft contact lens on the eye.

PURPOSE: Silicone-elastomer soft contact lenses (SCLs) adhere to the cornea during wear, whereas silicone-hydrogel soft contact lenses exhibit adequate on-eye movement. One explanation for the observed immunity to binding of silicone-hydrogel lenses is that some interstitial water is expelled during blinking, therefore maintaining a more stable post-lens tear film (PoLTF). We examine quantitatively whether or not water can be squeezed by hydrodynamic flow through a silicone-hydrogel membrane driven by the applied lid force during a blink. METHODS: A rigid, porous-disk model of a contact lens was devised to calculate the relative settling rates of a permeable versus a completely impermeable SCL. The settling rate depended strongly on the value of the hydraulic permeability for pressure-driven water flow through the lens. Because the hydraulic permeability of water through silicone-hydrogel materials is not well-known, we measured this value. At steady state, water was forced through flat membranes of representative lens materials under known pressure drops. The resulting volumetric flows were measured by following the transient rise height of water in a vertical, precision-bore glass capillary. Darcy's law permitted calculation of the hydrodynamic permeability. RESULTS: The settling-rate model indicated that tear can be squeezed through a SCL only when the Darcy-law hydrodynamic permeability is greater than about 10 microm2 (i.e., greater than 10 Darcy). Our measurements for silicone and HEMA hydrogel membranes reveal hydrodynamic permeabilities of the order 10(-8) microm2, almost 9 orders of magnitude smaller than that necessary to initiate hydrodynamic flow through a SCL. CONCLUSIONS: We conclude that the squeeze-through mechanism cannot quantitatively account for the observed on-eye movement of silicone-hydrogel lenses. Also, we find that the lid-applied pressure cannot squeeze enough water out of a SCL during a blink to stabilize the PoLTF. Neither a squeeze-through nor a squeeze-out mechanism can maintain a stable PoLTF and prevent adherence.

Blinking↗

Free vascularised osteocutaneous filet flap for covering, that permitted sensitive terminal weight-bearing by a thigh stump after transfemoral amputation.

We covered a transfemoral amputation stump with a modified free filet flap including the calcaneus. The flap survived, resulting in lengthening of the femur, improved distal weight-bearing, preserved sensitivity of the stump, and the design of a prosthesis with terminal loading of the femur rather than an ischial contained prosthesis.

Adult↗

Myoelectric control of a computer animated hand: a new concept based on the combined use of a tree-structured artificial neural network and a data glove.

This paper proposes a new learning set-up in the field of control systems for multifunctional hand prostheses. Two male subjects with a traumatic one-hand amputation performed simultaneous symmetric movements with the healthy and the phantom hand. A data glove on the healthy hand was used as a reference to train the system to perform natural movements. Instead of a physical prosthesis with limited degrees of freedom, a virtual (computer-animated) hand was used as the target tool. Both subjects successfully performed seven different motoric actions with the fingers and wrist. To reduce the training time for the system, a tree-structured, self-organizing, artificial neural network was designed. The training time never exceeded 30 seconds for any of the configurations used, which is three to four times faster than most currently used artificial neural network (ANN) architectures.

Amputees↗

A study of technical changes to lower limb prostheses after initial fitting.

There is little published material in recent years about the use of lower limb prostheses in an elderly amputee population. In this study the authors were interested in the technical changes to lower limb prostheses after a first limb fitting procedure in a post-rehabilitation population in The Netherlands. The process of fitting a prosthesis and the technical changes to the artificial limb in the first year afterwards are studied.

Aged↗

Equilibrium and movement control strategies in trans-tibial amputees.

This study was aimed at identifying changes in equilibrium and movement control strategies in trans-tibial amputees (TTA) related to both the biomechanical changes and the loss of afferent inflow. The coordinations between equilibrium and movement were studied in traumatical TTA and in controls during transition from bipedal to monopodal stance. TTA failed to perform the task in a high percentage of trials both when the sound and the prosthetic limb were supporting. Significant differences were also found between TTA and controls in the duration of the weight transfer phase, in the length of the initial centre of pressure (CP) displacement and in the electromyographic (EMG) patterns. Despite adaptive posturomotor control strategies, transition from bipedal to monopodal stance remains a difficult task to perform for TTA, both when the supporting limb is the affected one and when the sound one is. The results of this study are discussed with respect to the rehabilitation programme and the prosthesis design for transtibial amputees.

Adult↗

Evaluation of the psychophysical detection threshold level for vibrotactile and pressure stimulation of prosthetic limbs using bone anchorage or soft tissue support.

In the present study the psychophysical detection threshold levels mechanical stimulation of 32 prosthetic limbs were determined. Prosthetic limbs were anchored to the bone by means of an implant (n=17) or supported by a socket enclosing the amputation stump (n=15). Detection threshold levels were assessed for pressure and vibratory stimulation of the prosthesis and the limb at the contralateral side (control). Following vibratory stimulation, thresholds were increased on an average 20% for socket prostheses. but approached those of the control for bone-anchored prostheses. For pressure stimulation, thresholds were increased up to 60% for socket prostheses and 40% for bone-anchored prostheses compared to the control. While bone-anchored prostheses yielded significantly lower threshold levels than socket prostheses, there was no significant difference between both treatments regarding pressure stimulation. Results were applicable to both upper and lower limb amputees. It could be concluded that detection thresholds for pressure and especially vibratory stimulation of prosthetic limbs were generally higher than for control limbs. The outcome was related to the prosthetic limb design with bone-anchored prostheses yielding better perception than socket prostheses.

Adult↗

Changes in interface pressure and stump shape over time: preliminary results from a trans-tibial amputee subject.

Interface stresses and stump shape were measured during sessions over a two-month interval on a trans-tibial amputee subject. Results from thirteen transducer sites monitored during four sessions showed greater interface pressure changes over time at anterior sites than at lateral or posterior locations. There was a trend of decreased pressure with stump swelling and increased pressure for stump atrophy. During one session in which stump shape was monitored over a 23.1 min interval after ambulation, stump swelling was localised. Swelling tended to increase in the regions of initial enlargement, as opposed to redistributing through different areas over time. Regions of swelling were anterior lateral and posterior proximal, areas of thick underlying soft tissue. Identification of localised areas of swelling and atrophy and understanding of their effects on interface pressures could be used to improve individual socket design.

Adult↗

Non-surgical options to autologous finger transplants.

This case report describes the rehabilitation path of a man who sustained severe burns to his body and extremities as a result of a bushfire. The fingers of both hands were amputated except the thumbs and although he was a candidate for autologous transplant, declined this option for various reasons. Bilateral prostheses were made and resulted in a significant improvement in functional outcome without the need for surgery. Prostheses are practical alternatives to surgery and should be considered in selected patients.

Amputation, Surgical↗

Prosthetic foot roll-over shapes with implications for alignment of trans-tibial prostheses.

Roll-over shape is introduced as a significant characteristic of prosthetic feet. The roll-over shapes of the Flexwalk, Quantum, SACH, and SAFE prosthetic feet were determined using three methods; two involving quasi-static loading and one dynamic loading. The results show that foot roll-over shape properties obtained by quasi-static and by dynamic methods are similar. Relationships between foot roll-over shape and the alignment of trans-tibial prostheses are introduced that suggest ways to align trans-tibial prostheses without walking trials and iterations. The relationships may explain what prosthetists attempt to accomplish when they dynamically align a trans-tibial limb. They also explain why prosthetic feet with different mechanical properties usually necessitate different alignments, and may explain why a number of gait studies of trans-tibial amputees do not show major gait differences when walking is executed on various kinds of prosthetic feet.

Amputation, Surgical↗

Ultrasound study of the motion of the residual femur within a trans-femoral socket during gait.

This study analyses the motion of the residual femur within a trans-femoral socket during gait using ultrasound data from two simultaneously transmitting transducers connected to two ultrasound scanners. Calibration tests accurately established the orientation of the two transducers mounted on the lateral wall of the socket. Relative positions of the ultrasound image of the femur were measured on video playback. Motion of the residual femur, relative to the lateral wall of the socket, at any instant during gait may be estimated, if the relative positions of the two transducers and the motion of the ultrasound image are known. A consistent pattern of femoral motion during 10 gait cycles is displayed graphically. The femoral motion in this paper is expressed as abduction/adduction or flexion/extension relative to the socket. However, without a full gait analysis study, the orientation of the socket relative to the ground or relative to the pelvis cannot be determined. Only one ultrasound scanner may be available for clinical use. Hence data collection may be restricted to only one transducer during gait. In order to simulate the single transducer mode, the ultrasound data recorded during the 10 previous gait cycles, was averaged at any instant of the gait cycle. The angular orientation of the femur was calculated based on the averaged data. Similar patterns of femoral motion were obtained irrespective of the technique adopted.

Accidents, Occupational↗

Principal structural testing of trans-tibial prosthetic assemblies: specimen preparation.

A simple alignment apparatus and the method of transferring the offset test load to the prosthetic assembly through an aligned mandrel for the principal structural tests in accordance with ISO 10328 is presented. The new alignment apparatus was used to prepare test specimens consisting of traditional laminated prosthetic sockets, adaptors, shanks and foot blocks. The alignment apparatus proved useful in ensuring proper orientation and positioning of the components relative to one another as well as to the loading coordinate axes. The sockets and the other components achieved the maximum load specifications during the static failure tests and no failure of components was observed in the cyclic tests.

Artificial Limbs↗

Lower limb amputation. Part 2: Rehabilitation--a 10 year literature review.

Ten years after the ISPO consensus conference on amputation surgery, a search of relevant publications in the Rehabilitation-prosthetics-literature over the years 1990-2000 was performed. The main key-words in this research were: "lower limb, amputation, human and rehabilitation". One hundred and four (104) articles were assessed by reading and from these the authors selected 24 articles. These articles are summarised, under several subheadings in this review article, focussing especially on quality of life, functional outcome and predictive factors.

Activities of Daily Living↗

Lower limb amputation. Part 3: Prosthetics--a 10 year literature review.

This paper is intended as a follow-up to the ISPO Consensus Conference on Amputation Surgery. It reviews all the literature on lower limb prosthetics published after 1990. The review was considered under six categories: feet, knees, hips, thermoplastics, liners/suspension and computers.

Amputation, Surgical↗

Standing interface stresses as a predictor of walking interface stresses in the trans-tibial prosthesis.

Interface pressures and shear stresses within the socket, in standing and walking, were measured for two unilateral, male, trans-tibial amputee subjects, during two sessions each. The ratios of equal weight-bearing standing stresses to peak walking stresses showed regional variation, ranging from 0.24:1 for pressure over the anterior region to 1.01:1 for resultant interface shear stress over the lateral region. Interface stresses in standing were only moderate predictors of peak walking stresses. The best correlation coefficient between standing in full weight-bearing and peak walking stress was 0.88 for pressure over the lateral region. As the amputees progressed from minimal to full weight-bearing in standing, and then to walking, the interface stresses increased in a nonlinear fashion, consistent with the assumption that the anterior tibia provides much resistance to the bending moment in the sagittal plane during walking.

Adult↗