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At least 325 records · Page 18Linked to original sources
PubMed1999

Loudness scaling revisited.

The present work was undertaken in an attempt to evaluate whether it is reasonable to expect that categorical loudness scaling can provide useful information for nonlinear hearing aid fitting. Normative data from seven scaling procedures show that the individual procedures relate the perceptual categories differently to sound level and with a substantial between-subject variance. Hearing-impaired data from four studies demonstrate that the inverse slope of the loudness function varies linearly with hearing loss and with a constant variance. In relation to hearing aid fitting, the slope can, in most cases, be predicted from the hearing loss with an accuracy within the range of a normal finetuning. For the fitting of nonlinear hearing aids, the statistical properties of both normal and impaired loudness functions are equally important. The present analysis strongly suggests that categorical loudness scaling cannot, in general, provide significant information for the fitting process.

Auditory Threshold↗
PubMed2003

[The reconstruction of three-dimension morphology of proximal femur].

OBJECTIVES: To reconstruct the morphology of the proximal femur and measure the parameters of them by means of the computer-aided design (CAD) in order to provide help to the design and research of the domestic prosthesis, event for the selection of the adapted implant for the doctors before operation. METHODS: The data of 160 healthy Chinese proximal femur images were obtained by the PHLLIP SR7000 computer tomography. The correlative parameters were measured exactly by medical imaging software. Then the imaging data were input into an computerized contouring program which generates the three dimensional coordinates representing periosteal and endosteal contours of the femur for each CT slice. Though the computer-aided design (CAD) software, the three-dimensional solid model was reconstructed by the vectorisation of image contours. In the circumstance of CAD system, the bone axis is defined as the line across the geometric center of the cross-section of the isthmus and 20 mm above the lesser trochanter mid-point. We measured the parameters of the endosteal and periosteal dimensions of the medullary canal. RESULTS: The parameters of the medullary canal measured with the reconstructed normal Chinese femur have significant difference from that measured with the Caucasian's. The extracortical and endosteal parameters of male have significant differences from most of female's. However, there were no significant differences in endosteal width between different age groups in two gender groups. From the proximal to the distal femur, the intersection angles between the longest mediolateral endosteal diameters of the slices and the plane of the femoral neck were increased. CONCLUSIONS: The reconstructive femur contains more information and can be cut at arbitrary levels which means it is facility to the research of the Morphology of the Proximal femur and the measurement of relative parameters. It is necessary to design the prosthesis which fit anatomic parameters of the Chinese femur. It needs to further study whether the gender factor will be considered in the prosthesis design. The angle between the anteversion and the helitorsion at the level 20 mm above the lesser trochanter midpoint should be noticed by the implant designers and doctors.

Aged↗
PubMedDate not supplied

Inaccurate fit of implant superstructures. Part II: Efficacy of the Preci-disc system for the correction of errors.

The Preci-disc prosthetic system for dental implants is designed to compensate for casting inaccuracies and to reduce stresses generated on the superstructure and implant components. This laboratory study compared stresses induced on the implant superstructure with various sizes of vertical discrepancy of fit, with and without the application of the Preci-disc system. A series of test casts carrying four abutment replicas were fabricated incorporating various sizes of discrepancies (10 to 100 micrometers) relative to a master superstructure. The stress generated on the superstructure was quantified using photoelastic stress analysis. It was found that the Preci-disc system was effective in reducing stresses induced on the surface of the implant superstructure particularly with greater discrepancies of fit (60 to 100 micrometers).

Composite Resins↗
PubMed2000

Imaging of the painful lower limb stump.

Several postoperative complications associated with pain may develop in the stump of an amputated lower limb. Clinical findings are often nonspecific; however, radiologic evaluation, especially with magnetic resonance (MR) imaging, is useful in the early diagnosis of these complications, thereby helping minimize physical disability with its psychologic and socioeconomic implications. Conventional radiography can demonstrate evidence of osseous origins of pain (eg, aggressive bone edge, heterotopic ossification, osteomyelitis) and should be the first imaging study performed after clinical examination. Videofluoroscopy can help evaluate improper prosthetic fit by demonstrating abnormal residual limb motion, piston action, rolling of soft tissues, and abnormal angle between the limb axis and the prosthesis during gait. Ultrasonography can demonstrate inflammatory changes in the stump as well as soft-tissue fluid collections. However, MR imaging is the modality of choice when clinical and other imaging findings are indeterminate. Because of its high spatial and contrast resolution, MR imaging can demonstrate subtle inflammatory changes, fluid collections, cancers, neuromas, and subtle traumatic bone lesions. Knowledge of various surgical and rehabilitation techniques is required for accurate diagnosis of complications associated with stump pain. Correct diagnosis allows choice of the most appropriate therapy, which may involve treating the stump, remodeling the prosthesis, or both.

Amputation Stumps↗
PubMed1980

Below knee amputation and rehabilitation of amputees.

Of 373 below knee amputations, the healing rate was 82 per cent, primary healing occurring in 73.3 per cent. A permanent prosthesis was fitted on 283 patients. We attribute this success to the multidisciplinary team approach, the skilled surgical technique, the use of an intraoperative prosthesis and the patients motivation and cooperation.

Adult↗
PubMed2005

Sand-casting technique for trans-tibial prostheses.

A sand-casting technique for trans-tibial sockets was applied to 28 amputees, and the prosthetic fit observed through transparent check sockets. The results were better than historical reports of fittings with plaster of Paris casting by qualified prosthetists. The fit was consistently and evenly larger than the stump, but total contact could be achieved by applying three (two to five) stump socks. This would normally be considered on the high side of a good fit.

Adult↗
PubMed1997

The future of cochlear implants.

Remarkable progress has been made in recent years in the design and application of processing strategies for cochlear implants. Most notably, use of the new spectral peak (SPEAK) and continuous interleaved sampling (CIS) strategies have provided large improvements in speech reception performance compared with prior strategies (NIH Consensus Statement, 1995; Skinner et al., 1994a; Wilson et al., 1991). All major manufacturers of multichannel implant systems, including Advanced Bionics Corp., Bionic Systems, Cochlear Pty. Ltd., and Med El, now offer CIS or CIS-like strategies in their speech processors. The SPEAK strategy was developed by Cochlear Pty. Ltd and continues to be one of the options available in that company's devices. The principal purpose of this editorial is to present some of the many possibilities for further improvements in performance. To the extent that such possibilities are realized, implant systems of the future may be quite different from present systems, with different processing strategies, electrode designs, telemetry features, and fitting procedures.

Cochlear Implants↗
PubMed2002

Clinical evaluation of factors influencing toric soft contact lens fit.

PURPOSE: Some knowledge of the orientation position of toric soft lenses is required as part of the fitting process. Although it is known that factors such as lid anatomy, lens design, and fit are important, there is little detailed understanding of how these relate to toric lens orientation. The purpose of this study was to evaluate various patient and lens factors that might influence toric soft lens fit and to determine the predictor variables for lens orientation. METHODS: This was a clinical study in which 45 subjects were fitted with a prism-stabilized, mid-water, cast-molded, back surface toric soft lens. The lens was representative of commonly used designs for frequent replacement toric soft lenses. Patient and lens fit variables were assessed, including a range of lid topography features, which were measured using a digital photographic technique. RESULTS: The main patient factors associated with lens orientation and stability were degree of myopia, palpebral aperture, and several angles relating to lid anatomy. Greater upward incline of the temporal lids was associated with increasing inferior-temporal lens orientation; lower myopia and smaller palpebral aperture size were associated with more stable lens orientation. The principal lens fit characteristics affecting lens orientation were postblink movement and lens tightness. Less movement was associated with more stable lens orientation, and increased tightness was associated with slower reorientation speed. Weaker but significant correlations were also shown between a number of other patient and lens variables. CONCLUSIONS: A number of patient factors and lens fit characteristics influencing toric soft lens orientation were identified. The findings fall short of allowing practitioners to accurately predict toric lens orientation; however, they do provide some factors to consider when fitting toric soft lenses.

Blinking↗
PubMed1996

Adaptive fitting of hearing instruments by category loudness scaling (ScalAdapt).

The introduction of programmable as well as non-linear hearing instruments has shown that audiogram-based fitting procedures are inappropriate for meeting the individual needs of hearing aid users with sensorineural loss. Particularly the present and future development of hearing instruments with advanced analog and digital signal processing requires suitable fitting procedures. In this context, we developed an adaptive fitting strategy (ScalAdapt) using category loudness scaling. In this paper the procedure is described and tested using programmable 3-channel AGC instruments. However, it can be modified for any other hearing aid design. The underlying idea is to normalize the aided loudness perception for two input levels, one around the most comfortable level (MCL) and the other just below the uncomfortable level (UCL), as anchor points in each channel by interactive fine-tuning of the fitting parameters (channel gain, compression onset, compression ratio, etc.). The benefits of ScalAdapt have been evaluated by a field test study in 17 experienced hearing aid users. The results showed that ScalAdapt provides consistently higher objective (speech recognition in noise) and subjective benefits (self-assessment inventory) than for instance NAL-based fittings.

Hearing Aids↗
PubMed1986

Revision of failed hip surface replacement arthroplasties with a bipolar prosthesis. Three case reports with two- to three-year follow-up observations.

Three cases of an isolated femoral component failure of a hip surface replacement were treated by use of a press-fit bipolar prosthesis to articulate with the retained acetabular cup. At two to three years post-surgery (average, 31 months), these three conversions had good clinical function and maintained an acceptable radiographic appearance. While no optimal long-term solution currently exists for failed hip surface replacements in young adults, this rather straightforward surgical conversion may have a role to play in the interim management of some of these patients.

Adult↗
PubMed1999

Amplification for infants: selection and verification.

Hearing aid fittings for children under the age of 1 year provide many challenges to the audiologist. This article offers guidelines for assessment, hearing aid selection, verification, and follow-up for infants with hearing loss. The importance of early intervention and the consideration of new technologies are emphasized in this article. Case studies illustrate various aspects of infant hearing aid fittings.

Correction of Hearing Impairment↗
PubMed2005

Is fluorescein pattern analysis a valid method of assessing the accuracy of reverse geometry lenses for orthokeratology?

BACKGROUND: The aims of this study were to investigate the relative frequencies of correct identifications of variations in the fit of conventional rigid gas permeable (RGP) lenses and reverse geometry lenses (RGL) from fluorescein pattern analysis by orthokeratology (ortho-k) practitioners and non-ortho-k practitioners and to determine whether fluorescein pattern analysis is sensitive for assessing ortho-k lens fittings. METHODS: Slides of fluorescein patterns of different lens fittings were shown to the practitioners, who were asked to identify the ideal, flatter, flattest, steeper and steepest lens fittings. RESULTS: Observed frequencies of correct identifications of most of the conventional RGP lens fittingss were not significantly different from the expected frequencies for both groups of practitioners. The observed frequencies of correct identifications of all of the RGL fittings were either not significantly different or were lower than the expected frequencies. CONCLUSION: The relative frequencies of correct identifications of fluorescein patterns of both conventional RGP lens and RGL fittings by experienced ortho-k practitioners were not different from those by non-experienced ortho-k practitioners. Practitioners from the two groups were not always able to diagnose conventional RGP lens and RGL fittings adequately from fluorescein pattern analysis alone. Fluorescein pattern analysis alone may not be sufficiently sensitive for assessing ortho-k lens fitting.

Contact Lenses↗