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PubMed1992

Estimation of the loudness of tinnitus from matching tests.

To correct for the influence of recruitment when the loudness of tinnitus is measured by a balance test in an ear with sensorineural hearing loss, an averaged loudness function was devised, which converts the sensation level (SL) of tinnitus into an estimate of the effective loudness level. This is essentially the same as a phon scale except for the difference in reference level, and is defined as the equivalent SL of the tinnitus as if measured in an ear with a bone-conduction threshold of 0 dB HL at a frequency between 500 Hz and 4000 Hz. Using this function, the median estimated loudness of tinnitus from 301 randomly selected patients was 15 dB 'effective loudness level' with a maximum of more than 60 dB. A nomogram was made for clinical use to determine the effective loudness level easily from the SL of tinnitus and the bone-conduction HTL of the test ear. Although somewhat approximate, the effective loudness level is considered to be an unbiased loudness estimate of tinnitus under the condition that only the SL of tinnitus and the bone-conduction HTL are available, and makes it easier to appreciate the actual loudness compared with a complex loudness unit such as on the sone scale.

Adolescent↗
PubMed2000

Influence of age, type of audiometry and child's concentration on hearing thresholds.

Surprisingly little evidence is available in children between the ages of 3 and 7 years on the effect on hearing thresholds of the method of audiometry and of the developmental ability to concentrate and to respond. The Trial of Alternative Regimens in Glue Ear Treatment (TARGET) is a large, national, multi-centre trial of surgical intervention in children with otitis media with effusion (OME) that offers an opportunity to study these effects. Of 1517 children, aged between 3.25 and 6.75 years, reaching the selection stage, 4.5% were unable to give reliable air-conduction thresholds. A further 3% (i.e. 7.5% in all) could not give reliable bone-conduction thresholds. This inability was greatest in the youngest children. During air-conduction testing, a significantly greater proportion (p <0.005) of children were recorded as having only 'fair' or 'poor' concentration on conventional audiometry than with play audiometry. On the other hand, the magnitude of the effect of poor concentration, as rated 'fair/poor' versus 'good', was slightly greater on play as opposed to conventional audiometry (+5 dB versus +3 dB). Although statistically significant, the age of the child had only a very small effect on the air- or bone-conduction thresholds, once the type of audiometry, concentration and the presence of OME had been controlled for. It is concluded that adequately informative thresholds are usually obtainable by conventional audiometry in this age group, even if the concentration is recorded as 'fair' or 'poor'. However, when conventional audiometry is not feasible, play audiometry should be attempted in the 3-5-year-old age group.

Acoustic Impedance Tests↗
PubMed1989

Sensorineural high-frequency hearing loss after drill-generated acoustic trauma in tympanoplasty.

Tympanoplasty can cause a sensorineural hearing loss by a mechanism of acoustic trauma. Although this lesion appears to be relatively infrequent in clinical practice, we believe that its low apparent incidence is caused when clinicians fail to assess the auditory frequencies above 8000 Hz. Twenty-four patients with normal bone-conduction audiometric thresholds scheduled for tympanoplasty were assessed with an electro-stimulation, bone-conduction high-frequency audiometer which can measure hearing frequencies up to 20 kHz before and after surgery. A measurable hearing loss was found in the upper limits of the audible frequencies in 9 patients (37.5%), and was considered important in 4 of them (16.7%). This hearing loss was recorded above the upper frequency limit of conventional audiometers. The findings in this study indicate that drilling of the temporal bone can impair the hearing level in the high frequencies in a significant number of patients. High-frequency audiometry is a very sensitive tool to assess any damage caused to the inner ear by surgical procedures carried out in the middle ear and temporal bone.

Adolescent↗
PubMed1993

Thyroid hormone induces earlier onset of auditory function in neonatal rats.

The effect of thyroid hormone injection on the development of auditory function in neonatal rats was evaluated using auditory nerve-brainstem evoked responses (ABR). The hormone induced earlier onset of auditory function. In order to differentiate between conductive and sensorineural factors, both air-conducted (AC) and bone-conducted (BC) ABR responses were recorded. Neonatal rats were injected with thyroxine (T4), or with saline (control animals), from day of birth (post-natal day-PND-0), daily, until PND 9. AC- and BC-ABRs were recorded from PND 6 up to PND 20. It was found that both AC- and BC-ABR thresholds were lower in the T4-injected rats up to PND 15, after which no difference was found between the two groups. This indicated earlier maturity of both conductive (external and middle ears) and sensorineural (inner ear) factors and is probably due to the earlier appearance in the blood of higher T4 levels, following injection, than that occurring naturally during the neonatal period in these animals.

Animals↗
PubMedDate not supplied

The Beltone 5b artificial mastoid: theoretical characteristics and performance measurements.

Early versions of the Beltone artificial mastoid system were designated as model 5A. Later versions were designated as model 5B due to design modifications which changed the mechanical impedance parameters. The theoretical impedance characteristics of the 5B were considerably lower than for a comparison 5A. Compared with a B & K model 4930 (new pad) artificial mastoid, the 5B had a lower impedance (closer to ANSI values) from 500 to 2000 Hz and a slightly higher impedance at 250, 3000, and 4000 Hz. Discrete and continuous output voltage measurements with a constant input revealed that the performance of the 5B was also different compared with a 5A and the B & K model 4930 for different vibrator types. Bone conduction thresholds for a Radioear B-70A, B-71, and B-72 vibrator were obtained on 30 trained normal-hearing listeners. Adjusted threshold force levels needed to achieve normal-hearing bone conduction thresholds are presented for calibrating bone vibrators in clinical use with a Beltone 5B artificial mastoid.

Adult↗
PubMedDate not supplied

Analysis of the mechanical impedance of bone-anchored hearing aids.

Some patients who need hearing aids are unable to use an apparatus which transmits the sound via the external ear canal and have to use a bone conduction hearing aid. The bone vibration transducer of this aid is applied to the skin over the mastoid process and the sound is transmitted via the soft tissue and bone to the cochlea. The pressure needed to apply the transducer often gives the patient discomfort and the damping effect of the soft tissue gives poor quality of the sound transmitted. Advances in the ability to permanently implant foreign material in the body and perform permanent skin penetration has made it possible to develop a bone-anchored hearing aid. Fourteen patients have been equipped with such hearing aids. To be able to give these patients the best hearing aid, a new transducer has to be constructed to match the new situation. The impedance of the bone-anchored titaniumscrew/skull has been studied and the resistance and reactance of the mechanical impedance have been measured. The influence of a damping soft tissue layer over the bone has been analyzed. The difference between the impedance of the skull and the impedance of the soft tissue + skull was in the order of 10 to 25 dB depending on the frequency.

Acoustic Impedance Tests↗
PubMed1985

Marine turtle middle-ear anatomy.

The middle-ear structures from 5 Atlantic Loggerhead (Caretta caretta) and 1 Atlantic Ridley (Lepidochelys kempi) marine turtles from dead specimens found stranded in the lower Chesapeake Bay were dissected and examined superficially and by light microscopy. The marine turtle middle ear is poorly adapted as an aerial receptor in mammalian and reptilian terms. However, it appears well designed as a peripheral component of a bone conduction system. The thick tympanum, while disadvantageous as an aerial receptor, likely enhances low-frequency bone conduction hearing. The columella directly couples the cochlea and saccule so that its movement would stimulate each end organ. Turtle hearing is probably an integration of both outputs.

Animals↗
PubMed1994

Resonance frequencies of the human skull in vivo.

Patients with skin penetrating titanium implants in the temporal bone, for attachment of bone-anchored hearing aids, have made it possible to investigate the free-damped natural frequencies (resonance frequencies) of the human skull in vivo. The resonance frequencies of the skull of six subjects were investigated. Teh resonance frequencies were extracted from two frequency response functions (acceleration/force) measured on each subject: One point measurement where the force and acceleration were both measured at the same point, and one transcranial measurement where the acceleration was measured contralaterally. Between 14 and 19 resonance frequencies were identified for each subject in the frequency range 500 Hz to 7.5 kHz. The two lowest resonance frequencies were found to be on the average 972 (range 828-1164) and 1230 (range 981-1417) Hz. The relative damping coefficients of all resonances were found to be between 2.6 and 8.9%. Due to the relatively high damping coefficients, it is assumed that the resonance frequencies do not significantly affect bone conducted sound. In the transcranial measurements, however, a few large antiresonances were found which may affect bone-conducted sound. Intersubject variations were large, probably due to individual variations in skull geometry and in mechanical parameters. The results were shown to be consistent with previous results obtained on dry skulls. No obvious correlation between lowest resonance frequency and skull size was found.

Adult↗
PubMed1995

Age and hearing function in patients with chronic otitis media.

The effect of age on hearing function was assessed in 897 patients with chronic otitis media. Preoperatively, 3% of chronic ears were found to be totally deaf, anacusis being most frequent in patients over 60 years of age. Severe sensorineural hearing loss (preoperative bone conduction threshold worse than 30 dB) was observed in 10% of the patients, and the mean bone conduction thresholds elevated with increasing age. Sensorineural hearing loss was significantly more common in patients with cholesteatoma than in patients with chronic otitis media without cholesteatoma. Conductive hearing loss was less severe in paediatric patients than in patients over 30 years of age. Postoperative hearing results of paediatric patients did not differ significantly from those of adults. In contrast to some earlier studies, average postoperative hearing gain was as good in elderly patients as in younger patients.

Adolescent↗
PubMed1992

Background noise in rooms used for pure-tone audiometry in disability assessment.

Background noise limits for audiometry are determined by the effects of masking and are specified in international standards. The standards provide for audiometric testing over a range of audiometric frequencies extending down to 500 Hz or lower. The lowest frequency of testing is an important factor determining the admissible noise, and for certain applications it is appropriate to consider the limits applicable to testing over a more restricted range. Assessment of hearing disability in the UK is generally based on a consideration of pure-tone hearing threshold levels in the frequency range 1 kHz upwards. A modification of the standardized noise limits is proposed which allows some relaxation appropriate to this higher minimum frequency. For air-conduction audiometry, these modifications affect only the permissible background noise in the frequency range below 1 kHz. Where bone-conduction audiometry is required in order to quantify a conductive component of the hearing loss, the measurements need to be made on both ears with the non-test ear masked in both cases; the external background noise will thus only be heard monaurally and this justifies a correction to the noise limits compared with those appropriate to bone-conduction audiometry without masking.

Audiometry, Pure-Tone↗
PubMed1992

Cochlear function after stapedectomy.

The short-term and long-term results of stapedectomy for eliminating the conductive element and improving the hearing in patients with otosclerosis are highly satisfactory all over the world. The delayed sensorineural hearing loss which continues after successful stapedectomy may be due to the operation itself or due to the natural history of the disease. The study was conducted on 80 patients with unilateral stapedectomy with a minimal follow-up period of 1 year. We found that bone conduction values at each frequency in operated ears were stable with marked improvement at 2,000 Hz, on the other hand, the bone conduction thresholds in non-operated ears significantly deteriorated (p less than 0.001). The speech discrimination score was significantly improved in the operated group (p less than 0.001). An explanation for the cochlear changes in operated and non-operated ears is presented.

Adolescent↗
PubMed1995

Long-term results for the Xomed Audiant Bone Conductor.

The Audiant Bone Conductor is now used worldwide. Results consistently demonstrate that when used on patients within the recommended criteria, hearing thresholds are improved to within 10 dB of the preoperative bone conduction threshold. In this article, comparisons are made with the reported results of the Audiant versus other comparable bone conduction devices, or with surgical procedures for conditions such as congenital aural atresia.

Auditory Threshold↗
PubMed1983

Children with persistent otitis media. Audiometric and tympanometric findings.

Audiometric and tympanometric findings were compared among 129 patients with clinically manifest persistent otitis media (OM) with effusion. Ears with thick effusion (mucoid OM) had significantly larger air-bone gaps and higher prevalence of flat tympanograms than either of the thin effusion types (purulent [POM] or serous OM [SOM]) or ears with no effusion (dry). Ears with thin effusion (POM and SOM) had similar air-bone gaps, thresholds for air and bone conduction, and prevalences of flat and underpressure tympanograms. Ears with no effusion had significantly smaller air-bone gaps, slightly poorer bone conduction thresholds, and lower prevalence of flat tympanograms than ears with effusion (MOM, POM and SOM). Ears with clinically manifest OM and no effusion at tympanocentesis appear to represent patients with a spontaneously resolved episode of OM with thin effusion (POM or SOM) or with ears that evacuated during anesthesia prior to tympanostomy.

Acoustic Impedance Tests↗
PubMed2006

Clinical results after stapedotomy: a comparison between the erbium: yttrium-aluminum-garnet laser and the conventional technique.

OBJECTIVE: The objective of this study was to assess whether the use of the erbium: yttrium-aluminum-garnet (Er:YAG) laser has negative effects on inner ear function and to compare the short- and long-term hearing outcome of patients undergoing conventional stapedotomy versus laser stapedotomy. STUDY DESIGN: Retrospective review of prospectively collected audiometric data of patients with otosclerosis operated on by one experienced surgeon. SETTING: Academic tertiary referral center. PATIENTS: A total of 266 stapes surgeries were evaluated for intraoperative findings, of which 209 patients were evaluated for preoperative and postoperative hearing thresholds after a 6- to 452-week (mean, 22 wk) audiological follow-up. INTERVENTION: One hundred fifteen (43%) of the operations were performed conventionally, using manual perforators for stapedotomy (Group A); in 115 (43%) surgeries, the perforators were used in combination with the Er:YAG laser (Group B), and in 36 (14%) operations, the Er:YAG was used exclusively for footplate perforation (Group C). MAIN OUTCOME MEASURES: Pure-tone audiometry was performed before surgery, 2 days postoperatively (bone conduction only) and at 5, 26, and 57 weeks postoperatively. RESULTS: A postoperative temporary threshold shift of the bone conduction could be found in all groups. In Group C, where the laser was used exclusively for footplate perforation, this threshold shift was not only the most significant, but also-in contrast to the other groups-not totally reversible. In all techniques, a satisfactory air-bone gap closure could be achieved. The best long-term results (96% of the patients had <or=20 dB air-bone gap after 57 wk) could be found in Group B. CONCLUSION: If certain rules to minimize inner ear trauma are followed, the Er:YAG laser is a safe tool in middle ear surgery. Combining both the laser and the conventional technique, instead of the separate use of either technique, leads to superior postoperative hearing results.

Adolescent↗
PubMed1980

[Ultrasound hearing by humans: objectivation with brain stem potentials (author's transl)].

Early acoustic evoked potentials (brain stem evoked response) may be received by bone conduction after ultrasound irritation (40 kHz). In comparison with the brain stem potential which is received by the some bone conduction by 4 kHz there are differences in the pattern of the potential and in the latency shift. It may be thought of a retro-cochleare perception of the ultrasound because of the 1 msec earlier potential.

Bone Conduction↗
PubMed2006

Effect of cochlear reserve on postoperative outcome in otosclerosis.

Patients with elevated bone conduction (BC) thresholds are not considered a good candidate for otosclerosis surgery. Sometimes, it might be difficult to decide to operate these patients considering relatively poor cochlear function. However, viewpoints may vary among otologists. This study was undertaken to compare hearing outcome following otosclerosis surgery in patients who had bone conduction (BC) thresholds >or= 30 dB, and to investigate whether BC thresholds >30 dB has a negative impact on hearing outcome. Medical records of 111 patients who had undergone otosclerosis surgery were reviewed. Of 111 patients, 83 had undergone stapedotomy, and 28 stapedectomy. The patients were grouped based on preoperative four-tone BC threshold. Eighty-seven patients had average BC threshold 30 dB, and constituted poor-cochlear reserve group. Pre- and postoperative air conduction (AC) and BC thresholds, air-bone (AB) gap, vocal audiometry results and amount of deterioration in BC were determined. Mean postoperative AB gap was almost the same in both groups (14 and 15 dB) (P > 0.05). Percentage of AB gap = 10 dB favored good-cochlear reserve group (41 vs 29%)(P > 0.05). Analysis of mean hearing gain was slightly in favor of good-cochlear reserve group (19 vs 15 dB) (P > 0.05). Better BC thresholds were obtained postoperatively in good-cochlear reserve group (P < 0.001). Deterioration > 10 dB in BC was observed in 5.7 and 12.5% of the patients with good- and poor-cochlear reserve, respectively (P > 0.05). Based on the results of this small sample-size study, even though BC threshold of 30 dB was not considered a negative factor for hearing gain, otosclerosis surgery might have detrimental effects on postoperative BC thresholds in patients who had BC thresholds >30 dB.

Adult↗
PubMed1979

Tympanoplasty: TORPS and PORPS.

We reviewed 106 cases in which PlastiPoreTM prostheses were used for ossicular reconstruction. In all cases a piece of cartilage was interposed between the prosthesis and the tympanic membrane graft to prevent the potential problem of prosthesis extrusion. With total ossicular replacement prostheses (TORPs) 55% closed to within 10 db and 85% closed to within 20 db of the bone conduction level. Closure to within 10 db of the bone conduction level was accomplished in 64% of partial ossicular replacement prostheses (PORPs) cases. These results are better than obtained previously with either ossicles or cartilage alone.

Ear Cartilage↗