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PubMed1988

Soft tissue reactions around percutaneous implants: a clinical study of soft tissue conditions around skin-penetrating titanium implants for bone-anchored hearing aids.

Some patients with hearing impairment cannot use conventional hearing aids. One solution for these patients is the use of bone conduction hearing aids; however, this kind of equipment is associated with several problems related to the necessity for a good contact between the transducer and the temporal bone. Direct bone contact would be an ideal solution provided that safe and reaction-free skin penetration and a safe and permanent bone anchorage could be achieved. Brånemark et al have developed a procedure to furnish edentulous patients with fixed bridges using titanium implants. This report is focused on the clinical status of the soft tissue adjacent to the 67 skin-penetrating devices in 60 patients. The patients have been followed between 3 and 96 months on 313 occasions, which represents a total observation time of 1515 months of clinical performance. Only one implant was extracted due to adverse skin reaction, giving a failure rate of 0.07% per month. This is comparable with the failure rate of cardiac pacemakers 0.02-0.04% per month).

Biocompatible Materials↗
PubMed1986

Consequences of conductive auditory impairment for binaural hearing.

Studies of persons with conductive hearing loss have revealed substantial degradations in binaural hearing abilities. Described here is a model based on the hypothesis that this degradation is due to high levels of bone-conducted signals relative to air-conducted signals. The model makes quantitative predictions for the effects of conductive impairment on measurements of interaural discrimination. Qualitative predictions for binaural advantages in detection and speech intelligibility are also made by employing auxiliary models. Generally, available data are consistent with the models, although strong tests have not yet been performed.

Audiometry, Pure-Tone↗
PubMed1998

Real-ear measurements in conductive hearing loss: discrepancies between probe-tube microphone measurements and sound field test results.

This study was designed to investigate earlier observations that probe-tube microphone measurements of insertion gain overestimates the functional gain received from hearing aids by users with significant conductive hearing losses. This was originally thought to be due to artefacts in the probe-tube measurement caused by middle ear pathology, but is now believed to be the result of the bone conduction stimulation of the ear exposed to high intensities of airborne sound during sound field threshold measurements. Since the functional gain must relate to the true aided benefit in such cases, these findings suggest that probe-tube microphone measurements in ears with significant air-bone gaps should be interpreted with caution.

Bone Conduction↗
PubMed1983

Turtle shells as an auditory receptor.

Evoked responses were obtained from the brainstem of seven box turtles (T. carolina) using air conducted stimuli and also vibratory stimuli applied directly to the carapace. Both stimuli elicited similar neural electrical responses that differed chiefly in sensitivity. The vibratory responses were lower in threshold and higher in amplitude than responses to air conducted clicks. Further, simultaneous masking of vibratory clicks by air conducted noise had negligible effects, whereas vibratory masking completely suppressed the responses to airborne sound, suggesting that the turtle ear is differentially sensitive to sound and vibration. Spinal blocking of somatic pathways had negligible effects on the vibratory-evoked responses, suggesting that the latter originate in the auditory system and are stimulated by bone conduction.

Animals↗
PubMed2001

The pathway for the transmission of external sounds into the fetal inner ear.

After at least 20 weeks gestation, the human fetus in utero is able to hear and respond to external and internal (maternal) sounds. The external sounds are attenuated by maternal tissues and fluids - higher frequencies by about 20 dB, and lower frequencies are only slightly reduced. The sounds in the amniotic fluid, which completely envelops the fetus, then reach the fetal inner ear by bone conduction. The sound pressure in the amniotic fluid induces skull vibrations which are transmitted directly into the contents of the cranial cavity (brain and CSF) and from there, presumably by fluid channels connecting them, into the cochlear fluids. A further stage of conductive attenuation is probably involved in this transmission. Since the fetus in utero receives oxygen by placental diffusion (less efficient than pulmonary diffusion), the fetal inner ear is hypoxic compared to that following birth (pulmonary oxygen diffusion). This leads to a reduction in the magnitude of the endocochlear potential, to a depression of cochlear transduction and amplification, and thus to an additional sensorineural component of threshold elevation in the fetus. Upon birth, these conductive and sensorineural attenuations are removed.

Amniotic Fluid↗
PubMed1987

Genetic and functional analysis of the otosclerosis-like condition of the LP/J mouse.

The LP/J mouse is the only available genetic model for otosclerosis. The otosclerosis-like condition of the LP/J mouse resembles the human condition in several ways, although there are differences in the two species in the most common locus of the dysplastic otic lesions. The mouse model would be more useful if its auditory dysfunction and genetic inheritance could also be compared with the human disease. Matings of the otosclerosis-like LP/J and the normal CBA/J inbred mice were used to generate F1 and backcross generations. The F1 showed neither functional (electrocochleographic) nor anatomical abnormalities, indicating a recessive nature of the mouse genetic disease. This is in contrast to some reports of dominance (with incomplete penetrance) of otosclerosis in humans. No evidence of X-chromosome-linked genetic influence was found in the mouse, in agreement with the human condition. These interpretations were confirmed in tests of the backcross of the F1 to the CBA/J parental genotype (BC). The anatomical and functional abnormalities were present in some of the backcrosses of the F1 to the LP/J parental genotype (BL). A comparison of bone-conducted and air-conducted electrocochleographic responses provided evidence for both conductive and sensorineural losses in the LP/J and BL mice.

Action Potentials↗
PubMed2003

Comparison of the bone anchored hearing aid implantable hearing device with contralateral routing of offside signal amplification in the rehabilitation of unilateral deafness.

OBJECTIVE: Monaural hearing imposes constraints under many listening conditions. The authors compared the effects of a semi-implantable bone conductor, the Entific bone anchored hearing aid, with conventional contralateral routing of offside signal amplification to assess rehabilitative benefit in adults with unilateral deafness. DESIGN: Prospective trials of subjects with unilateral deafness using benefit surveys, source identification testing, and hearing in noise testing. SETTING: Tertiary referral center, outpatient surgical and audiologic services. PATIENTS: Adults with unilateral deafness (pure tone average >90 dB, SD <20%) after acoustic neuroma excision (n = 7), meningitis (n = 1), sudden sensorineural hearing loss (n = 1), and sudden sensorineural hearing loss with chronic suppurative otitis media (n = 1). Entry criteria included normal hearing in the contralateral ear (pure tone average <25 dB, SD >80%). INTERVENTION: Subjects were fitted with contralateral routing of offside signal amplification devices for 1 month and tested with contralateral routing of offside signal before mastoid implantation of the deaf ear, fitting, and testing for bone anchored hearing aid. OUTCOME MEASURES: Subjects' assessment of experience with their devices and patterns of use, 2) source azimuth identification in noise test, and 3) speech discrimination in quiet and in noise under conditions of noise-front, noise-to-normal-ear, and noise-to-deaf-ear. RESULTS: There was consistent satisfaction with bone anchored hearing aid implantation and amplification, and poor acceptance of contralateral routing of offside signal amplification. Sound localization was poor at baseline and with both bone anchored hearing aid and contralateral routing of offside signal. Relative to baseline, contralateral routing of offside signal and bone anchored hearing aid produced significantly better speech recognition in noise under most conditions. The bone anchored hearing aid enabled significantly better speech recognition than contralateral routing of offside signal in quiet and in a composite of noise conditions. The advantages may relate to averting the interference of speech signals delivered to the better ear, as occurs with conventional contralateral routing of offside signal amplification. CONCLUSIONS: Preliminary data in subjects with normal monaural hearing indicate that vibromechanical stimulation with the bone anchored hearing aid overcomes some of the negative head shadow effects in unilateral deafness. The bone anchored hearing aid system, when placed on the side of a deaf ear, yields greater benefit in subjects with normal monaural hearing than does contralateral routing of offside signal amplification. It seems that this rehabilitative approach can expand the sound field of monaural listeners in further enhancing speech understanding. Observations suggest that further understanding of bone conduction as implemented in transcranial stimulation will guide further options for patients with monaural hearing. Longer follow-up will help to determine whether communicative skill improvements with the bone anchored hearing aid outweigh the disadvantages of implantation surgery, costs, and device maintenance.

Adult↗
PubMed1999

Comparison of stapes prostheses: a retrospective analysis of individual audiometric results obtained after stapedotomy by implantation of a gold and a teflon piston.

PURPOSE: Evaluation of hearing results after implantation of a Teflon piston (type Causse; Xomed Surgical Products, Jacksonville, FL) and of a pure gold piston (K-piston; Heinz Kurz GmbH Medizintechnik, Dusslingen, Germany), both with a shaft diameter of 0.4 mm in cases of otosclerosis requiring stapedotomy. An important difference between both prostheses is the difference in mass: the gold piston is three times heavier than the Teflon piston. METHODS: Retrospective analyses were carried out of the presurgery and postsurgery audiologic results obtained after primary stapedotomy by implantation of 62 Teflon pistons and 66 gold pistons. The results were compared according to mean values of several audiometric parameters. Furthermore, individual audiometric results have been evaluated with the "Amsterdam Hearing Evaluation Plots" (AHEPs) as a method for visual presentation of hearing results from each operated ear. With this method, "unsuccessfully" and "successfully" inserted prostheses can be recognized easily and a more realistic comparison between prostheses is possible. RESULTS: It was found that in the overall group the heavier gold prosthesis gives a significantly larger gain in air-conductive hearing at 2 kHz (p < 0.05) and in the speech frequency range 0.5 to 2 kHz (p < 0.05). There were no significant intergroup differences with regard to change in bone-conduction and air-bone gaps. Analysis of the hearing results of the subgroup that included only the "successfully" implanted prostheses according to the criteria of the AHEPs had mainly consequences for improvement of air-conduction thresholds: none of the intergroup differences were statistically significant. CONCLUSIONS: For a fair comparison between prostheses, it is necessary to take only the prostheses into account that are inserted properly and that are functioning under normal conditions with regard to transmission of sound vibrations. After analysis of the hearing results of these "successfully" implanted prostheses, a trend was noticed that the heavier gold piston gives more gain in the low- and mid-frequency range and the light-weighted Teflon piston gives more gain in the high-frequency range, although none of the differences were significant.

Adolescent↗
PubMed2006

A novel human osteoblast-derived severe combined immunodeficiency mouse model of bone metastasis.

OBJECT: One of the major difficulties of conducting bone metastasis research is the lack of adequate models for studying the bone-tumor microenvironment. The limitations of current in vivo models include the following: non-human tumor or bone, variable reproducibility, limited supply, and an inability to be easily manipulated. The objective of the present study was to develop a uniform and reproducible model of bone/spine metastasis by utilizing bone derived from human osteoblasts grown subcutaneously in severe combined immunodeficiency (SCID) mice with subsequent introduction of human carcinoma cell lines. METHODS: Human osteoblasts were serially passed in culture and induced to differentiate into mature osteoblasts. They were subsequently loaded on hydroxyapatite-coated collagen sponges and implanted subcutaneously into the SCID mice. After allowing the bone to mature for 8 weeks, tumor cell suspensions were implanted percutaneously into the bone. The bone-tumor complexes were subsequently harvested, decalcified, and prepared for histological examination. CONCLUSIONS: The authors have developed a novel, reproducible SCID mouse model of bone/spine metastasis by using bone derived from human osteoblasts and subsequently introduced human tumor lines. They believe this model will be useful for studying the basic biology of bone metastases.

Animals↗
PubMedDate not supplied

Recruitment in conduction deafness. Observations using a midline loudness balance test.

A midline loudness balance test was made in 10 normal ears with blocked ear canals and in 104 conductively deaf ears with loss not exceeding 45 dB. The test was made by giving the tones simultaneously in the ears at 10, 60 and 80 dB sensation levels for 500 and 2 000 Hz. In the normal group the midline balance method indicated no reduction from the threshold differences at any of the three levels whereas significant reductions occurred in all groups of conduction deafness. The occurrence of true partial recruitment in conduction deafness demonstrated by ABLB (Fowler's) test was attributed to altered middle ear mechanics, loud tones stimulating the inner ear relatively more effectively than tones near the threshold level. The midline balance method is more closely dependent upon bone conducted sounds and on the altered relative movements of the labyrinthine windows.

Audiometry↗
PubMed2006

Revision BAHA Surgery.

The osseointegrated auditory implant (BAHA) is a system used for hearing rehabilitation through direct bone conduction. Although BAHA surgery is not difficult, the surgeon must observe meticulous technique to prevent complications. Indications for revision BAHA surgery can be divided into (1) failure of fixture osseointegration; (2) bone overgrowth; or (3) skin reaction or skin loss. This article discusses the conditions that might predispose a patient to require BAHA revision, and the steps, if any, that can be taken to prevent these complications. Specific surgical steps for revision of each of these three conditions are also addressed.

Bone Conduction↗
PubMed1976

[Late results of stapedectomy after 15 years (author's transl)].

Stapedectomy in Otosclerosis in using polyethylene struts or stainless-steel wire protheses results in permanent correction of the postoperative gap. The use of stainless-steel wire protheses however is successful with 94% of the patients regarding the postoperative gap, compared to 89% of the patients in using the polyethylene struts. The postoperative decrement of bone conduction is statistically significantly lower in the stainless-steel wire protheses than in polyethylene struts.

Audiometry↗
PubMed2003

[Bone-anchored hearing aid (BAHA): report of 2 cases].

In this first case report in Japan, we described 2 patients treated using a bone conductive hearing aid with skin-penetrating implant, or bone-anchored hearing aid (BAHA). Both suffered from chronic otitis media and had received bilateral canal down tympanomastoidectomy. Case 1 was a 61-year-old woman with a conventional air conductive hearing aid in her right ear. There was no aural discharge in either ear. A pure-tone average showed 82.5 dBHL (air), 44.3 dBHL (bone) in the right ear and 93.8 dBHL (air), 48.8 dBHL (bone) in the left ear. Case 2 was a 38-year-old woman with a conventional hearing aid in her left ear, from which there was persistent aural discharge. A pure-tone average showed 48.8 dBHL(air), 15.0 dBHL (bone) in the right ear, and 60.0 dBHL(air), 20.0 dBHL(bone) in the left ear. Both underwent BAHA implant in the right ear without adverse reaction during 9 months of postoperative follow-up after surgery. No difference was seen in the aided hearing level or speech discrimination score between BAHA and air conduction hearing aids but both patients preferred to BAHA because of its greater comfort and audibility.

Adult↗
PubMed1998

Type IV tympanoplasty revisited.

OBJECTIVE: There has been a great improvement in the material and design of prosthesis used for total ossicular reconstruction in recent years. As a result, the indication for type IV tympanoplasty has become more restricted. The long-term follow-up of type IV tympanoplasties performed by the author is presented. STUDY DESIGN AND SETTING: This is a retrospective study of 31 patients who had type IV tympanoplasties performed by the author at the ear, nose, and throat clinic of a district general hospital. PATIENTS: All the patients had chronic active otitis media with total loss of ossicles that were unsuitable for ossicular reconstruction. INTERVENTION AND MAIN OUTCOME MEASURES: The preoperative and postoperative air and bone conduction thresholds of all the patients who underwent type IV tympanoplasty were measured. RESULTS: Twenty-six percent of the patients had a postoperative hearing level <40 dB and 58% had an air-bone gap <30 dB. The indication for type IV tympanoplasty can be categorized into four groups: severe atelectasis, patients with cleft palate, erosion of the footplate, and surgery on the better-only hearing ear. CONCLUSION: There still is a place for type IV tympanoplasty in modern otology.

Audiometry, Pure-Tone↗
PubMed2005

Success rate in revision stapes surgery for otosclerosis.

OBJECTIVE: The aim of this study was to evaluate the hearing results of revision stapes surgery performed because of previously failed operations and to determine the causes of failure. STUDY DESIGN: Retrospective review of revision stapes operations. SETTING: Tertiary referral center. PATIENTS: Sixty-three consecutive revision stapes operations were performed in 56 patients over a period of 12 years (1992-2004). The indication for revision surgery was recurrent or persistent air-bone gap greater than 20 dB after primary surgical treatment of otosclerosis of the oval window. RESULTS: All patients were operated on to improve hearing. Sixty-three revision stapes operations resulted in closure of the air-bone gap to 10 dB or less in 52.4% of cases. The average postoperative air-bone gap was 13.1 dB, and the mean pure-tone average improvement was 12.9 dB. In six patients (9.5%), revision surgery produced no change in hearing, and in four (6.3%) the hearing decreased by 5 dB or more. In one patient, the operation resulted in a profound hearing loss. Prosthesis malfunction was the most common primary cause of failure (60.3%). The original prosthesis was replaced with a new one in 48 cases. In 30 of these (62.5%), closure of the air-bone gap to within 10 dB was achieved. In 15 cases, the prosthesis was not replaced, and in only four of these (26.7%), closure of the air-bone gap within 10 dB was obtained (p < 0.022). CONCLUSION: Revision stapes surgery is less likely to be successful than the primary operation. Closure of the air-bone gap to within 10 dB was achieved in 52.4% of patients. The success rate was better in cases where the original prosthesis was replaced with a new one. The risk for decreased bone-conduction threshold does not seem to be higher than in primary surgery.

Adolescent↗
PubMed1999

Sensorineural hearing loss in chronic otitis media.

Although many studies have demonstrated an association between chronic otitis media (COM) and sensorineural hearing loss (SNHL), there still remains disagreement about the relationship. A retrospective study was conducted to examine the relationship between sensorineural hearing loss and chronic otitis media. Forty-one patients met the following criteria: unilateral COM and no history of head injury, meningitis or previous otological surgery. The differences in preoperative bone conduction threshold between diseased and control (contralateral normal) ear were statistically significant (P < 0.01) and varied from 5.24 to 9.02 dB across the frequency range. The effect of duration of disease on the degree of SNHL was also analysed but no correlation was found. The presence of cholesteatoma and/or ossicular erosion was not associated with a significantly increased risk of sensorineural hearing loss.

Adolescent↗
PubMed1994

The effect of conductive hearing loss on the masking-level difference: insert versus standard earphones.

Previous studies have indicated that the masking-level difference is reduced in listeners having conductive hearing loss, even when sensation level is controlled. According to the crosstalk hypothesis, this deficit can be explained in terms of reduced binaural cues at the level of the cochleas, due to acoustic contributions from the bone conduction route. It is possible that such a deficit can be overcome through the use of insert earphones, because such transducers provide a high degree of interaural attenuation. In this study, NoSo and NoS tau thresholds were measured in normal-hearing subjects and in subjects having hearing loss due to otosclerosis, using both standard TDH earphones encased in NAF-48490-1 circumaural cushions and deeply seated Etymotic 3A insert earphones. Masking noise was presented both at a fixed sound-pressure level and at a fixed sensation level. The results did not indicate consistently larger MLDs with insert earphones for either group of subjects, for either type of presentation level. The MLDs of the hearing-impaired subjects often remained abnormally small even when the insert transducers were used and the noise was presented at a fixed SL. Whereas acoustic crosstalk appeared to have a role in the results obtained, other factors (perhaps related to long-term hearing threshold asymmetry and/or interaural phase mismatch) also were apparently involved.

Acoustic Impedance Tests↗
PubMed2005

Ossiculoplasty using incus interposition: hearing results and analysis of the middle ear risk index.

OBJECTIVE: To determine the immediate hearing result and the long-term stability of sculpted incus interposition in ossiculoplasty and evaluate the utility of the middle ear risk index in predicting hearing outcome in these cases. PATIENTS: One hundred thirty-seven surgical patients. STUDY DESIGN: Review of 137 patients who underwent ossiculoplasty using autologous or homologous sculpted incus interposition. INTERVENTIONS: Ossiculoplasty using autologous or homologous sculpted incus interposition. METHODS: Retrospective chart review, using the guidelines delineated by the Committee on Hearing and Equilibrium of the Academy of Otolaryngology-Head and Neck Surgery for the evaluation of results for the treatment of conductive hearing loss. RESULTS: The mean preoperative air bone gap was 26.8 dB, and the mean postoperative gap was 18.6 dB. Twenty-seven percent of patients were closed to within 10 dB, and 66.4% were brought to within 20 dB of the postoperative bone conduction line. Average time to the last postoperative audiometric testing was 15.8 months, with a range of 2 to 62 months. A mean air bone gap change of -0.2 dB was noted. Four patients had more than a 10 dB deterioration in conductive hearing loss. There were no cases of graft extrusion. Each ear operated upon in our series was fully scored using the middle ear risk index, and an index total was calculated. No statistical associations could be demonstrated in any group between the postoperative air bone gap and the middle ear risk index subcategories or total. CONCLUSIONS: Sculpted autologous or homologous incus interposition provides hearing success comparable with current allograft prosthesis studies, has a very low extrusion rate, and remains stable over time. We were not able to demonstrate an association between the middle ear risk index and hearing results in this subset of patients.

Adolescent↗