Estimation of the benefit of bone-anchored hearing aids

Implantable bone conduction hearing aids are a valuable alternative to conventional aids for those who cannot use a conventional air conduction aid or find it difficult to use because of an aural discharge, most commonly due to chronic otitis media. Previously reported series of the use of a bone-anchored hearing aid (BAHA) come from the originators of this device, and an independent report of their benefit and use, especially in previous air conduction aid users, would be of value. Twenty-three patients were evaluated at least 6 months after implantation of a BAHA. All 7 previous bone conduction aid users were delighted with their BAHA, reporting increased comfort and hearing benefit that was backed by audiometric evidence. Of the 16 individuals who previously used an air conduction aid, 11 (69%) were delighted users of their BAHA. Unfortunately, the other 5 (31%) reverted to solely using their air conduction aid. There was no obvious predictor as to how these individuals might have been identified prior to implantation. In particular, their pure tone thresholds, especially the bone conduction thresholds, were no different from those of the 11 BAHA users. However, in free field audiometry, the users gained superior benefit from their BAHA compared to their air conduction aid, whereas the nonusers did not. In conclusion, in all series to date, previous users of a conventional bone conduction aid have been delighted users of a BAHA and have gained superior audiometric benefit. This is not necessarily the case with previous air conduction aid users.(ABSTRACT TRUNCATED AT 250 WORDS)     

Immobilization effects on contractile properties of aging rat skeletal muscle

Recent advances in miniaturization have provided clinicians with hearing aids that can be comfortably inserted as far as the bony portion of the ear canal. It is possible to take advantage of these deeply inserted hearing aids in new ways. For example, the physical vibrations of microphone and receiver components may be used to improve hearing aid gain through bone conduction. Three cases are presented that will introduce this phenomenon for two transcranial CROS fittings and for one unilateral otosclerosis fitting. In each case, functional gain measurements under headphones were obtained with the hearing aid receivers acoustically plugged. Considerable gain was still present. Potential benefits, ramifications, and side effects are discussed.     

Radio frequency hearing: electrostrictive detection and bone conduction

A hearing aid patented by C. R. Schafer and supposedly based on detection of an amplitude-modulated carrier wave in the auditory cortex was re-examined. It is shown here that the hearing aid actually works by bone conduction of sound. It is concluded that detection of the modulation signal occurs by electrical nonlinearities and electrostriction in the bones of the face and skull.     

Clinical applications of transcranial bone conduction attenuation in children

It is a common belief that there is no significant transcranial attenuation across the skull by bone conduction (BC). In 32 children with proven unilateral sensorineural hearing loss the unmasked bone thresholds were measured on each side. There was a significant attenuation of BC at 4 kHz. Transcranial attenuation of BC at 4 kHz may explain the difference in sound perception between the two ears when bone conduction amplification is used. Further research should be undertaken to identify the better cochlea in mixed hearing losses.     

Hearing aid use and benefit and uptake of aural rehabilitation services by New Zealand hearing aid wearers

AIM: To provide the first extensive survey in New Zealand of hearing aid use and benefit and the accessibility of Hearing Association services. METHOD: A mail-out questionnaire was used to survey 197 Auckland adult hearing aid wearers regarding patterns of hearing aid use and benefit and the accessibility of Hearing Association aural rehabilitation services. RESULTS: Hearing aid benefit was moderate and was not related to age or hearing aid use variables. Knowledge and usage of local rehabilitation services was limited. Perceived functions of the Hearing Association included adult audiometry and counselling. Respondents wanted assistance with hearing aid management and assistive listening devices. Physical access, financial and time constraints were seen as barriers to using rehabilitative services. DISCUSSION: It appears that there is not a simple relationship between perceived benefit or satisfaction and the amount of time people wear their hearing aids. The low level of awareness and participation in Hearing Association services is consistent with the underutilisation of such services found previously.     

Presbyacusis, hearing aids and aging

This paper considers the factors of presbyacusis and age-related psychological changes in older adults in terms of their effects on the use or potential use of hearing aids as a means of improving aural communication. Data are presented on the prevalence of hearing impairment and the extent of hearing aid use in aging listeners. Four major classes of presbyacusis are described (sensory, neural, metabolic, and cochlear conduvtive) and a hearing aid prognosis is made for each type of disorder. It is shown that aging produces deficits in pure-tone thresholds, the speech reception threshold, and speech discrimination, but not all losses can be 'corrected' with a hearing aid. Binaural (stereophonic) devices are psychoacoustically superior to monaural devices; however, behavioral and personality changes in older patients often create problems of adaptation to the binaural aid. These changes may also affect the fitting of an aid and the patient's ability to learn to use it. Some practical suggestions are offered on the evaluation of hearing aids and it is emphasized that adequate orientation and counseling are typically required if hearing aid treatment is to be successful in presbyacusis.     

Comparison of two digital hearing aids

OBJECTIVE: The objective of this investigation was to compare real and perceived benefit for two currently marketed digital hearing aids, the Oticon DigiFocus and the Widex Senso. The hearing aids have different philosophies of design and fitting strategies; as a result, it was hypothesized that there would be performance differences. DESIGN: Twenty subjects with documented sensorineural hearing losses were fit with each of the two digital hearing aids. After 4 wk of use with each hearing aid, a battery of objective and subjective tests was completed to assess hearing aid benefit. RESULTS: No significant differences were found between the hearing aids as revealed by the objective testing of speech recognition and self-report inventories of hearing aid benefit. The DigiFocus was shown by real ear measurements to provide more high-frequency gain than the Senso. The Widex Senso was preferred by 13 of the 20 subjects (seven of 10 of the new hearing aid users). This may be explained, in part, by the increased high-frequency gain provided by the Oticon DigiFocus, which was perceived as having greater "harshness." CONCLUSIONS: Based on the results of this investigation, neither hearing aid processor was shown to be superior to the other. In addition, the least amount of objective benefit was shown in the presence of background noise.     

Input-output function of the acoustic reflex and objective hearing aid evaluation

Hearing aid evaluation procedures should mainly consider hearing properties in the most comfortable loudness intensity range. This applies to both subjective and objective methods. With regard to this aspect, input-output characteristics of the acoustic reflex were investigated for speech noise and narrow-band noise (0.5, 1, 2 and 4 kHz) stimulation. In these terms, hearing aid evaluation can be understood as an approximation of pathological input-output functions to the normal range by suitable hearing aids. After normal input-output characteristics have been established, we report on first experiences with this fitting procedure. Frequency-specific elicitation of the stapedial reflex with and without hearing aid enables a compensation for hearing impairment in accordance with frequency-dependent dynamic properties.     

The effect of drinking water fluoridation on the natural course of hearing in patients with otosclerosis

The effect of drinking water fluoridation on the course of hearing of non-operated otosclerotic ears was assessed in an area where the natural waters have a very low fluoride content. The study population consisted of 150 patients with surgically proven otosclerosis. Patients having an additional known cause of hearing loss were excluded from the study. Every patient had a follow-up of at least 5 years, the mean follow-up period being 8.8 years. At last follow-up examination, air conduction thresholds of patients drinking fluoridated tap water were found to be significantly better than those of patients drinking fluoride-poor water, likewise there were significant differences in bone conduction thresholds at 1, 2, and 4 kHz. It was concluded that drinking water fluoridation has a beneficial effect on hearing levels of non-operated otosclerotic ears.     

Gender differences in blue collar workers' use of hearing protection

In this study, the Health Promotion Model (HPM) was used as the basis for a structural equation model of male and female blue collar workers' self-reported use of hearing protection devices (HPDs). Overall use did not differ by gender; in addition, self-efficacy and barriers to use of HPDs were the two best predictors of this behavior for both men and women. Despite the similarities in HPD use and the most important predictors of that use between men and women, the predictive models differed by gender in several ways. Significant predictors of use among men also included age and value of use of HPDs. For women, ethnic status and plant site were additional significant predictors of use. Because the influences of plant site and gender on self-reported use of HPDs could not be separated in this study, further research should address worksite culture and assess differences by gender. Knowledge of these differences will aid development of more effective interventions and may increase the use of hearing protection.     

Improvements in speech perception by children with profound prelingual hearing loss: effects of device, communication mode, and chronological age

The present investigation expanded on an earlier study by Miyamoto, Osberger, Todd, Robbins, Karasek, et al. (1994) who compared the speech perception skills of two groups of children with profound prelingual hearing loss. The first group had received the Nucleus multichannel cochlear implant and was tested longitudinally. The second group, who were not implanted and used conventional hearing aids, was tested at a single point in time. In the present study, speech perception scores were examined over time for both groups of children as a function of communication mode of the child. Separate linear regressions of speech perception scores as a function of age were computed to estimate the rate of improvement in speech perception abilities that might be expected due to maturation for the hearing aid users (n=58) within each communication mode. The resulting regression lines were used to compare the estimated rate of speech perception growth for each hearing aid group to the observed gains in speech perception made by the children with multichannel cochlear implants. A large number of children using cochlear implants (n=74) were tested over a long period of implant use (m=3.5 years) that ranged from zero to 8.5 years. In general, speech perception scores for the children using cochlear implants were higher than those predicted for a group of children with 101-110 dB HL of hearing loss using hearing aids, and they approached the scores predicted for a group of children with 90-100 dB HL of hearing loss using hearing aids.     

The Jungle and American Muckraking Movement

During the end of the 19th century and the beginning of the 20th century, a group of American journalists and writers called ＂muckrakers＂ launched a muckraking movement aiming at unveiling shady deals, social evils and injustices. Upton Sinclair＇ s The J     

Hearing aid for and clinical picture of deaf children with multiple handicaps

The evolution and the frequency of early detection technics, as well as the choice made in noenatalogy increase to a considerable extent the number of children who show besides an already bad clinical picture in the development field important hearing deficiencies. We bring forward a few clinical reflections resulting from our experience in hearing aid of these children.     

The rehabilitation of conductive hearing impairment

Conductive hearing loss (CHL) usually is amenable to surgical correction. At times, patients with CHL may not be candidates for surgical correction, or they may refuse to undergo the procedure. In such a situation, the patient should be encouraged to try hearing aids, either conventional or bone conduction, depending on the pathologic condition. After a discussion of bone-conduction implantable hearing aids, the article discusses congenital aural atresia, otosclerosis, and the management of CHL after infratemporal fossa approach and transtemporal approaches.     

Active electronic cochlear implants for middle and inner ear hearing loss--a new era in ear surgery. I: Basic principles and recommendations on nomenclature

Hearing aids have fundamental disadvantages: (1) stigmatization of the patient; (2) the sound is often found to be unsatisfactory due to the limited frequency range and undesired distortion; (3) in many patients, the ear canal fitting device generally necessary leads to an occlusion effect; (4) acoustic feedback when amplification is high. Conventional hearing aids transmit sound into the ear canal via a small microphone. Sound has the disadvantage of requiring high output sound pressure levels for its transmission. This along with the necessary miniaturization of the loudspeaker as well as the resonances and reflections in the closed ear canal contribute to the disadvantages mentioned. In contrast, implantable hearing aids do not make sound signals but micromechanical vibrations. An implantable hearing aid has an electromechanical transducer instead of the loudspeaker of a conventional hearing aid. The hearing signal does not leave the transducer as sound but as a mechanical vibration which is directly coupled to the auditory system bypassing the air. This implantable hearing aid is either coupled to the tympanic membrane, the ossicular chain, the perilymph of the inner ear, or the skull. An implantable hearing aid is expected to have: 1 Better sound fidelity than a hearing aid 2 No ear canal fitting device, free ear canal 3 No feedback 4 Invisibility Requirements on electronic hearing implants designed for patients with conductive hearing loss differ from those on implants for sensorineural hearing loss. Conductive hearing loss requires the implant to replace the impedance transformation, thus being an impedance transformation implant (ITI). In various respects, the demands on an ITI are lower than the demands on an electronic hearing aid for patients with sensorineural hearing loss. The latter are mostly patients with a failure of the cochlea amplifier (CA). A damage to the CA is clinically discernible by a positive recruitment and loss of otoacoustic emissions (OAE). Since these patients form the majority of cases with sensorineural hearing loss, an active hearing implant for such patients should partially replace the function of the CA. Therefore, the suggestion is to refer to a CAI (cochlea amplifier implant). The implant expressions ITI (for patients with conductive hearing loss) and CAI (for patients with sensorineural hearing loss) used in this context allow nomenclatural association with the CI (cochlear implant) for complete inner ear failure as well as with the BSI (brainstem implant) in the case of hearing nerve failure.     

The evaluation of lyophilized polymer matrices for administering recombinant human bone morphogenetic protein-2

Novel unitary devices, prepared by lyophilization of viscous solutions of sodium carboxymethylcellulose (CMC) and methylcellulose (MC), were evaluated as sustained-release delivery systems for recombinant human bone morphogenetic protein-2 (rhBMP-2). In vitro characterization of the unitary devices, which contained rhBMP-2-loaded poly (d,l lactide-co-glycolide) (PLGA) bioerodible particles (BEPs), was conducted over a 2-month period. Determinations included buffer uptake, mass and molecular weight loss and rhBMP-2 release from the unitary devices. CMC devices imbibed approximately 16 times their weight of buffer, while with MC, equilibrium uptake was approximately 6 times the dry weight of the devices. Overall mass loss percentages were approximately 55 and 35%, respectively, for CMC and MC devices. rhBMP-2 release from the devices was essentially a triphasic process: an initial phase during which "free" protein (rhBMP-2 present on the surface and within the pores of the PLGA BEPs) was released, a lag period during which no release was discerned, and then release of "bound" rhBMP-2 (protein adsorbed to the BEPs). The release of bound protein correlated with the mass loss of the polymer which began after 3 weeks. Release from the unitary devices was lower than that from the BEPs alone, due to a retardation effect of the gelled CMC/MC polymers. In rabbits in which full-thickness cranial bone defects were created, the implants were well tolerated and induced significant new bone growth during an 8-week evaluation period. The CMC devices appear to have induced bone earlier (at 2 weeks), but this did not affect eventual 8-week results. CMC devices without rhBMP-2 appeared to provide some bone conduction, in contrast to the blank MC devices.     

Auditory perception with level-dependent hearing protectors. The effects of age and hearing loss

Auditory perception with hearing protectors was assessed in three groups of subjects, two with normal hearing, but differing in age, and one with moderate bilateral sensorineural hearing loss. Individuals were tested with the ears unoccluded, and fitted with each of two level-dependent ear muffs and their conventional level-independent counterparts. One of the former devices provided limited amplification. In each of these five ear conditions, the threshold of audibility for one-third octave noise bands centered at 500, 1,000, 2,000 and 4,000 Hz, consonant discrimination, and word recognition were measured in quiet and in a continuous impulse noise background. The results showed that the attenuation of sounds (i.e. the difference between protected and unoccluded thresholds) in quiet did not vary as a function of age or hearing loss for any of the four protectors. In noise, the difference between protected and unoccluded listening was close to zero, as long as hearing was normal. With hearing loss as a factor, there was a significant increment in the protected threshold, the amount determined by the device. Word recognition in quiet was adversely affected in normal-hearing listeners by the three attenuating devices but improved in noise relative to unoccluded listening. Amplification had a deleterious effect for both consonant discrimination and word recognition in noise. In hearing-impaired listeners, speech perception was impeded by all four muffs but less so in quiet with limited amplification.     

Effects of the severity and duration of lesions on the primary and anamnestic humoral responses of sheep to Dichelobacter nodosus and observations of natural resistance to footrot

Choice of outcome measure in reporting hearing results following otologic surgery, including the frequencies used and use of pre- or postoperative bone thresholds, varies from author to author. In this study, data from 550 ossicular reconstruction and pediatric tympanoplasty surgery patients were used to generate a variety of outcome measures, including pure-tone thresholds for frequencies from 0.5 kHz to 8 kHz and different frequency combination pure-tone averages (PTAs) and air-bone gaps. There were no significant differences between mean pre- and postoperative bone conduction thresholds for any of the frequencies from 0.5 to 4 kHz nor for a PTA of 1, 2, and 4 kHz. Mean postoperative air-bone gap differed by no more than 2 dB across six different frequency combination PTAs. If "success" is defined as a postoperative air-bone gap of less than 20 dB, the largest difference in success rate across the six frequency combinations was 5%. There was also little difference in mean postoperative air conduction PTAs for any of the combinations that include frequencies through 4 kHz. Choice of a more conservative or more liberal definition of success was more important than whether air-bone gap or air conduction PTA was used. The authors recommend that a standard reporting procedure be adopted that ensures presentation of the results in a format such that more direct comparisons can be made within the published literature.     

Hearing in a geriatric perspective

To assess whether hearing rehabilitation of older people can be improved by co-operation between the audiology and geriatric departments and the home service, 139 old and frail audiological patients were allocated to three groups with three different fitting procedures: 1) conventional fitting including verification of acoustical gain in the patient's ear; 2) home-fitting by hearing therapists, and 3) home-fitting by a specially trained geriatric nursing assistant, the home help also being present. Outcome was assessed by the ordinary questionnaire mailed to hearing aids users three to four months after fitting and by a geriatric evaluation procedure. The response rate in the conventionally fitted group was highly unsatisfactory (36%) and too small for further data-analysis. In the educational group a tendency was found towards better manipulation skills and significantly higher hearing aid use. However, the response rate was lower than in the geriatric group (71% compared to 81%), and no knowledge of hearing aid use was registered in the home service by this procedure. In the geriatric group a correlation was found between practical ability and use and satisfaction with the hearing aid. However, two thirds of the group were dependent on lasting help for the handling of the aid. Most patients in this group were already known by the hospital and home service, and the individual home help showed an interest in learning about hearing aid use. Home fitting by a joint audiological and geriatric effort in collaboration with the home help has proven feasible and valuable to both patient and home help. Extended co-operation is recommended between the health care and the social sector concerning hearing aid use.