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At least 829 records · Page 46Linked to original sources
PubMed1997

The influence of fluoridation of drinking water on the long-term hearing results of stapedectomy.

The long-term hearing results of stapedectomy were assessed in 294 patients with otosclerosis living in an area where the natural waters have a very low fluoride content. Only patients with an initially successful outcome were included. Patients having an additional known cause of hearing loss were excluded. The mean follow-up period was 9 yr. From the best hearing levels achieved 6 to 12 months after surgery, the mean air conduction thresholds showed an annual impairment of 0.4 to 1.1 dB/year and bone conduction thresholds an annual impairment of 0.5 to 1.0 dB/year. There was no significant difference between patients drinking fluoridated tap water and those drinking low-fluoride water. It is concluded that a daily sodium fluoride intake of 1 to 3 mg in a low-fluoride area is too small to have a significant effect on hearing impairment after stapedectomy.

Adult↗
PubMed2005

Stapedotomy in osteogenesis imperfecta: a prospective study of 23 consecutive cases.

OBJECTIVE: To prospectively evaluate the hearing results in surgically treated cases of stapes fixation in patients with osteogenesis imperfecta. STUDY DESIGN: A prospective study of osteogenesis imperfecta patients with stapes fixation. SETTING: One tertiary referral center. PATIENTS: Eighteen patients (23 ears) who underwent stapes surgery from 1994 to 2004 were prospectively included. INTERVENTION: Stapedotomy with vein graft interposition and reconstruction with a Teflon piston or a bucket handle (cup) prosthesis. MAIN OUTCOME MEASURES: Preoperative and postoperative audiometric evaluation using conventional audiometry. Air-bone gap, bone-conduction thresholds, and air-conduction thresholds were measured. Postoperative audiometry was performed at 6, 9, 12, 18, and 24 months after surgery and at a yearly interval thereafter. RESULTS: Overall, a postoperative air-bone gap closure to within 10 dB was achieved in 85.7% of cases. Postoperative improvement of air-conduction thresholds superior to 20 dB was found in 57% of cases. The postoperative bone-conduction thresholds were unchanged. CONCLUSION: This study shows that safe and successful stapedotomy is possible in cases of stapes fixation in patients with osteogenesis imperfecta.

Adolescent↗
PubMed1996

Mastoid surgery in the only hearing ear.

Every otologic procedure carries the risk of damage to the inner ear. On the other hand, cholesteatoma and uncontrolled tubotympanic disease can lead to partial or total sensorineural loss, as well as intracranial complications. Our experience of the surgical management of eight patients with an only hearing ear is presented. There were no dead ears in this series and no significant worsening of inner ear function. The air conduction pure-tone average was worse in two patients without change in bone conduction. Of the eight patients, six wear a hearing aid with success and two patients manage without an aid. The present small series confirms that patients at risk of anacusis from cholesteatoma or chronic suppurative otitis media can be offered, in experienced tertiary referral units, a safe method of stabilizing the ear and preserving useful hearing.

Adult↗
PubMedDate not supplied

[Electrophysiological study of cochlear damage in early otosclerosis and after stapedial surgery].

Otoesclerotic patients usually have neurosensorial hearing toss in addition to a predominantly conductive impairment, but there is no universally accepted explanation for this abnormality. The bone conduction threshold in tonal audiometry is accepted as a test of cochlear function. An early evaluation of damage to the cochlea arid acoustic nerve after surgery was made by studying 99 ears with BERA and latency/intensity curves to test cochlear function. We concluded that early damage was present. Postoperative cochlear damage was found in spite of successful surgery, but it was no greater than the damage present before surgery.

Audiometry, Pure-Tone↗
PubMed1986

The mechanical point impedance of the human head, with and without skin penetration.

The fact that a titanium screw can be implanted into the mastoid portion of the human skull, at the same time establishing a permanent, reaction-free skin penetration, has made it possible to attach a new bone conduction hearing aid directly to the skull. To understand and improve this new method of bone stimulation, the mechanical point impedance of the titanium screw-skull system was measured. The conventional point impedance of the skin-covered mastoid portion of the temporal bone was also measured and the difference in magnitude between the two impedances was calculated. An impedance head (Brüel & Kjaer 8001) and an FFT analyzer (Hewlett-Packard 5423) were used for mechanical point impedance measurements. Seven patients have been investigated. The magnitude of the impedance for the screw-skull system was found to be generally between 10 and 30 dB higher than that for the conventional skin-covered mastoid bone. One conclusion is that the conventional point impedance of the skin-covered mastoid portion of the human skull is essentially due to the properties of the skin and subcutaneous soft tissue. Another conclusion is that a much lower stimulation velocity is needed, with skin penetration, to produce a given hearing sensation.

Acoustics↗
PubMed2000

Measurement of thermal conductivity of bovine cortical bone.

The thermal conductivity of cortical bone was characterized experimentally. Specimens were taken from the mid-diaphysis of bovine femora, and the rate of heat transfer was measured in three orthogonal directions. The conductivity was found to be 0.58+/-0.018 W/mK in the longitudinal direction, 0.53+/-0.030 W/mK in the circumferential direction, and 0.54+/-0.020 W/mK in the radial direction. Because the directional differences are small, it is concluded that bovine cortical bone can be treated as thermally isotropic.

Animals↗
PubMed1999

Congenital absence of the long process of the incus.

OBJECTIVE/HYPOTHESIS: To review the case reports of three generations of one family, suffering from bilateral conductive hearing loss due to congenital absence of the long process of the incus. STUDY DESIGN: Review of the literature regarding hereditary congenital absence of the long process of the incus to determine its mode of inheritance such as autosomal dominant or X-linked. Also document the types and results of surgical repairs performed by previous investigators of this defect and compare them with the present study. METHODS: Three female patients of direct lineage. Mother, daughter, and granddaughter, who were personally seen, operated on, and followed up over a period of 26 years. RESULTS: All three female patients presented with similar symptoms and findings of hearing impairment since birth, with no history of ear infections, and with normal appearing tympanic membranes. However, they had severe conductive hearing loss with normal bone conduction and discrimination. Operative findings were identical in all three patients, with the incus ending in a blind stub, and with absence of the capitulum of the stapes. The type of ossicular reconstruction varied with the changing of times and advances in otologic surgery, as well as the prosthetic materials used. All three patients received improvement in their hearing, and this improvement has been maintained over the 26-year span of the study. CONCLUSIONS: Hearing loss due to congenital absence of the incus is uncommon but not rare. Interestingly, no other instance of inherited cases were reported in the literature. In this family the defect appears to be an inherited trait either due to an autosomal dominant mutation or an X-linked dominant inheritance. This abnormality is amendable to surgery, and any well-executed technique usually gives good hearing results.

Adult↗
PubMedDate not supplied

Degree of adaptability of the somatosensory cortex to change: prospects for integration of bone-mounted dental prostheses.

1. The topographic representation of the body surface in the somatosensory cortex provides an important model system for the in vivo study of neuronal plasticity, induced changes in somatotopy providing a direct measure of plasticity not available in most parts of the central nervous system. 2. Over the past two decades, animal experimentation in a number of laboratories has shown a remarkable degree of adaptability of the cortical representation following peripheral lesions and has had a widespread influence by challenging the once-accepted dogma that the brain is a structurally fixed organ. 3. Although some aspects of original stimulation will be missing, it is likely that receptors stimulated through bone conduction and compression by bone-mounted dental prostheses preserve some of the geometric and temporal relationships of original stimulation. By analogy with data obtained from the forearm representations, it would be expected that many features of the original cortical representations will be recreated. 4. There are also examples in the literature of perceptual learning without gross changes to the cortical representation (some being within a class of adaptability known as gain control) and it is likely that perceptual integration of many dental prostheses occurs within the limits of these neural adaptation mechanisms.

Adaptation, Physiological↗
PubMed2004

[The effects of tympanotomy tube insertion on distortion product otoacoustic emissions].

OBJECTIVE: To discuss the effects of tympanotomy tube insertion on distortion product acoustic emissions. METHOD: Twenty-six patients (29 ears) with B type of tympanogram and conductive hearing loss but their bone conductive threshold was less than 30 dB were selected and recorded the DPOAE audiogram with Smart OAE4.24 otodymic analyser before, shortly after and two weeks after tube insertion. Twelve normal subjects were selected as control. RESULT: The eliciting rate and amplitude increased after tube insertion. The difference in 1105, 1560, 2211, 4416 Hz were significant. The amplitude went up two weeks later. CONCLUSION: The amplitude of DPOAE can be influenced by otitis media with effusion, tympanic membrane perforation and tympanotomy tube, and improved after tympanotomy tube insertion, but it can't reach the normal level.

Adolescent↗
PubMed1989

[Experimental study of composites of bovine bone morphogenetic protein and bio-active glass ceramic implanted into surgically produced periodontal bony defects in dogs].

Bovine bone morphogenetic protein (bBMP) was incorporated with bio-active glass ceramic (BGC). The composite of bBMP-BGC and BGC were implanted into the surgically produced periodontal osseous defects in dogs. Observations at 10, 16, 20, and 24 weeks show that the implants of BMP-BGC have the ability of bone induction and enhance the regeneration of periodontal bony defects in a relatively short time, but the implants of BGC alone only have the ability of bone-conduction, these is no bone-induction ability, and made a more long time in repairing the periodontal bony defects.

Animals↗
PubMed1993

[Ventilation tube insertion for treating adult otitis media with effusion].

The etiologic factors and treatment of otitis media with effusion (OME) in children are well described and established. On the contrary, little has been published with regard to OME in adults and its treatment. To further investigate this problem, we reviewed the records of all adult patients who had received ventilation tube (VT) insertion for OME in VGH-Taipei from 1983 to 1986. There were 335 VT insertions performed on 140 adult patients whose follow-up periods were longer than 6 months. Among them, fifty patients received more than one VT insertion due to recurrence of OME in one or both ears. The average follow-up period was more than 4 years. The coexistence of nasal diseases was found in 46% of the adult OME patients. The mean extrusion time of the VT was 10.2 months. After VT insertions, the improvements of mean air conduction and mean air-bone conduction gap were 10.1 and 11.8 dB respectively. After the extrusion or removal of VT, there was no recurrence of OME in 50 ears (14.9%). Recurrence of OME occurred in 199 ears (59.4%). Dry persistent perforations of the eardrums were found in 27 ears (8.1%). Discharging persistent perforations were noted in 24 ears (7.2%). No recurrence of OME was observed in 24.2% of the ears with serous effusion fluids, whereas only 4.8% of the ears with mucoid fluids were free from recurrence during the follow-up period. Post-intubation otorrhea, which was the most common complication, developed in 92 ears (27.5%). Our results suggest that the recurrence rate of OME after extrusion of VT is high in the adult patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Female↗
PubMed1998

Management of labyrinthine fistula in middle ear cholesteatoma.

Labyrinthine fistula is a complication of chronic otitis media with cholesteatoma. Canal wall down tympanoplasty with partial mastoid cavity obliteration and complete removal of cholesteatoma matrix was adopted in five cases of labyrinthine fistula. The operation resulted in elimination of vertigo. Sensory hearing has been saved in two cases. Air conduction hearing improved in one case. In three cases whose air conduction deteriorated post-operatively, bone conduction worsened in two cases and remained unchanged in one case (Tympanoplasty type 0 was performed in the other one case.) During the follow-up period, otorrhea improved in all cases and there was no evidence of recurrence of cholesteatoma. If the hearing of the other ear is acceptable, we suggest one-stage canal wall down tympanoplasty with complete removal of cholesteatoma matrix and partial mastoid cavity obliteration. It provides low recurrence rate of cholesteatoma and there is no need of re-operation.

Adolescent↗
PubMedDate not supplied

Frequency response and output variations of Radioear B-71 and B-72 bone vibrators.

Frequency response curves were obtained for a Radioear B-71 and a B-72 bone vibrator with a revised Bruel and Kjaer model 4930 artificial mastoid. The curves for each vibrator were characterized by three resonant peaks which decreased in amplitude as frequency increased. The maximal output voltage variations of the artificial mastoid were less than or equal to 2 dB for each vibrator at all audiometric frequencies (+/- 3%), except for the B-72 at 4000 Hz where the variation was 6.9 dB. Overall, the findings were interpreted to question the use of a +/- 3% frequency tolerance for the generation and calibration of reference bone conduction thresholds.

Acoustics↗
PubMed1999

Objective calibration of bone conductors using otoacoustic emissions.

OBJECTIVE: To demonstrate a technique for objectively calibrating bone conductors on an individual basis using distortion product otoacoustic emissions (DPOAEs). DESIGN: Individual calibrations were obtained using DPOAEs recorded from a single ear of 21 normally hearing adults. Validity and robustness of the technique were investigated through subjective phase cancellation measurements and sensitivity analysis. RESULTS: Calibrations obtained using the DPOAE method were well supported by phase cancellation results. Intersession repeatability was good, and manipulation of the DPOAE data showed that the calculated calibration is relatively insensitive to small variations of emission magnitude. Bilateral stimulation through bone conduction did not display an apparent effect on emission magnitude in a single individual. CONCLUSION: Bone conductors can be accurately calibrated on an individual basis with good repeatability using DPOAEs. The technique is robust and offers an objective, noninvasive calibration method for research and specialized clinical applications. No training and only passive cooperation are required, making the procedure ideal for special groups such as children. A number of limitations will reduce the clinical utility of this technique. Important audiometric frequencies below 1 kHz cannot be tested because of noise, because individuals with significant hearing loss are unlikely to produce sufficient DPOAEs, and because commercial bone conductors typically have poor high-frequency response above 4 kHz.

Acoustic Stimulation↗
PubMed2002

Single photon emission computed tomography in otosclerosis: diagnostic accuracy and correlation with age, sex, and sensorineural involvement.

OBJECTIVE: To evaluate the accuracy of single photon emission computed tomography (SPECT) in detecting otospongiotic foci of the labyrinthine capsule in otosclerotic patients and to correlate the metabolic patterns detected by SPECT with age, sex, and sensorineural hearing loss. PATIENTS AND METHODS: Thirty-six patients with surgically confirmed otosclerosis and a control group of 12 subjects with normal hearing; each subject underwent SPECT study of the skull with (99m)technetium-diphosphonate ((99m)Tc-medronate). Statistical analysis of the results was performed by use of the Mann-Whitney U test. RESULTS: SPECT seemed to be very sensitive in differentiating otospongiotic bone from normal bone; in the affected group, only 2 of 72 ears yielded false-negative results (sensitivity 97.2%). Moreover, in the otosclerotic patients, the mean petrosa uptake value was higher than in the control group, a difference that was statistically significant (p < 0.0001). MAIN OUTCOME MEASURES: Regarding uptake in relation to patient age, an inverse relationship was observed between increased metabolic activity and age: the mean uptake index in the younger patients was significantly higher than that in the older patients (p < 0.0001). By contrast, no statistically significant differences were found between men and women (p = 0.1519). Comparison of SPECT alterations with bone conduction thresholds revealed a statistically significant correlation (p = 0.0002 and p = 0.0010) between increased metabolic bone activity and sensorineural involvement only in the younger group of otosclerotic patients. CONCLUSIONS: Diphosphonate bone SPECT is the only functional method that allows in vivo evaluation of disease activity, and it was highly sensitive in detecting otosclerosis. SPECT can be considered useful in the diagnosis of otosclerosis that is difficult to recognize, such as cochlear otosclerosis and far-advanced otosclerosis, and it could also find a place in evaluating the efficacy of medical therapy for otosclerosis.

Adult↗
PubMed1978

[Early and late functional hearing results from a modified technique for tympanoplasty (author's transl)].

This paper is a comparative study of the early and late functional results of tympanoplastic operations, as modified by Khan. Following such surgery, we examined 494 patients who had been operated on between 1970--1972 in the ENT Clinic of the Free University of Berlin (Klinikum Westend). Preliminary and final hearing results were recorded with the aid of sound audiograms, which were critically assessed by two different types of evaluations. These included the results of pure-tone changes and speech reception thresholds as achieved by the tympanoplastic operations. On the basis of socially useful hearing improvements, the functional results of cases operated in our clinic are above average. The hearing gain shown from post-operative controls to the final studies is especially satisfactory, since this also includes an improvement in bone conduction.

Acoustic Impedance Tests↗
PubMed2001

Active control of the volume acquisition noise in functional magnetic resonance imaging: method and psychoacoustical evaluation.

Functional magnetic resonance imaging (fMRI) provides a noninvasive tool for observing correlates of neural activity in the brain while a subject listens to sound. However, intense acoustic noise is generated in the process of capturing MR images. This noise stimulates the auditory nervous system, limiting the dynamic range available for displaying stimulus-driven activity. The noise is potentially damaging to hearing and is distracting for the subject. In an active noise control (ANC) system, a reference sample of a noise is processed to form a sound which adds destructively with the noise at the listener's ear. We describe an implementation of ANC in the electromagnetically hostile and physically compact MRI scanning environment. First, a prototype system was evaluated psychoacoustically in the laboratory, using the electrical drive to a noise-generating loudspeaker as the reference. This system produced 10-20 dB of subjective noise-reduction between 250 Hz and 1 kHz, and smaller amounts at higher frequencies. The system was modified to operate in a real MR scanner where the reference was obtained by recording the acoustic scanner noise. Objective reduction by 30-40 dB of the most intense component in scanner noises was realized between 500 Hz and 3500 Hz, and subjective reduction of 12 dB and 5 dB in tests at frequencies of 600 Hz and at 1.9 kHz, respectively. Although the benefit of ANC is limited by transmission paths to the cochlea other than air-conduction routes from the auditory meatus, ANC achieves worthwhile attenuation even in the frequency range of maximum bone conduction (1.5-2 kHz). ANC should, therefore, be generally useful during auditory fMRI.

Auditory Perception↗
PubMed2006

Hydrogen plasma surface activation of silicon for biomedical applications.

Silicon has gradually been recognized to be an essential trace element in the normal metabolism of higher animals, and the role of silicon in the human body has aroused interests in the biomedical community. In fact, the interactions between silicon-based devices and the human body such as biosensors and microelectromechanical systems (MEMS) often suffer from poor biocompatibility. In this work, hydrogen plasma immersion ion implantation (H-PIII) is conducted to improve the bioactivity or bone conductivity of silicon. In order to investigate the formation mechanism of bone-like apatite on the surface of the hydrogen implanted silicon wafer, two comparative experiments, hydrogenation and argon bombardment, are performed. The H-PIII sample exhibits an amorphous surface consisting of Si-H bonds. After immersion in simulated body fluids, a negatively charged surface containing the functional group ([triple bond]Si-O-) is produced and bone-like apatite is observed to nucleate and grow on the surface. The surface of the H-PIII silicon wafer favors the adhesion and growth of osteoblast cells and good cytocompatibility may be inferred.

Biomedical Engineering↗