[Pure-tone audiometry (air and bone conductive threshold test)].
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Audiometry, Pure-Tone↗
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[Postoperative result for tympanic membrane perforation].
Ears with tympanic membrane perforation show a wide range of pathophysiology from simple perforation to mobility impairment of the ossicular chain complicated by sclerotic and/or inflammatory lesions of the middle ear. In surgery on such ears, we determine checkpoints and proceed based on the order of procedure. We studied postoperative results for 37 ears of patients undergoing tympanoplasty in the 3 years from June, 1996 to May, 1999. Lesions accountable for mobility impairment of the ossicular chain were confirmed and removed in the order of calcified tympanic membrane, tip of malleus handle, around the anterior tympanic spur, and epitympanum. Success in improving in hearing was 89.2% overall. Conductive impairment (air conduction-bone conduction gap) left on the patch test was found to differ with the site and range of tympanic and middle ear lesions. This can serve as a guide in preoperatively predicting the type of operation required.
Adult↗
Mechanism of hearing loss in irradiated ears: a long-term longitudinal study.
A 10-year longitudinal follow-up study of hearing was conducted in patients with nasopharyngeal carcinoma (NPC) in order to elucidate the mechanism of hearing loss in irradiated ears. Ten NPC patients were subjected to a battery of audiological tests before irradiation and 6 months, 5 years, and 10 years after irradiation. The tests included pure tone audiometry, tympanometry, eustachian tube function testing, and myringotomy to confirm middle ear effusion. The prevalences of otitis media with effusion (OME) were 25%, 25%, 40%, and 25% at the 4 testing periods described above, respectively. The prevalences of chronic otitis media were 0%, 0%, 15%, and 25%, respectively. In myringotomized ears (n = 17), the mean hearing levels for both air conduction and bone conduction were preserved from the preirradiation period to 10 years after irradiation. In contrast, in grommeted ears (n = 3), the mean hearing levels for both air conduction and bone conduction deteriorated progressively from the preirradiation period to 10 years after irradiation. We conclude that hearing can be preserved in NPC patients 10 years after irradiation if middle ear inflammation is well controlled. We do not recommend grommet insertion in irradiated NPC patients with OME, as it may result in persistent otorrhea and hearing deterioration.
Acoustic Impedance Tests↗
Hearing levels of patients with otosclerosis 10 years after stapedectomy.
Hearing levels of 174 patients (213 ears operated on) with otosclerosis undergoing stapedectomy were analyzed. All patients had followup of 10 years or more, the mean follow-up period being 13.4 years. Eighty-seven ears (41%) underwent posterior crus stapedectomy, and in the remaining 126 ears (59%) a prosthesis was inserted. Large fenestra technique was used in all cases. In the long run, both air conduction and bone conduction thresholds of ears operated on showed remarkable deterioration from the best values obtained 6 to 12 months postoperatively. Ten years after surgery both air conduction and bone conduction thresholds of ears operated on were significantly worse than those of normal controls. At 10 years, 70 percent of the ears operated on had hearing levels (at 0.5 to 2.0 kHz) of 30 dB or better and 88 percent had 40 dB or better. At the last follow-up examination, in 90% of the patients the better hearing ear had a hearing level of 40 dB or better. In 90% of patients with bilateral otosclerosis who had operations in only one ear, the ear operated on had better hearing function than the opposite ear that had not been operated on.
Adult↗
Ethylene oxide sterilization impairs allograft incorporation in a conduction chamber.
Bone allograft processing often includes treatment with hydrogen peroxide for protein denaturation and sterilization by irradiation or ethylene oxide. The effect of these treatments on the osteoconductive properties of the graft was tested by measuring the new bone ingrowth distance into processed cancellous bone grafts in rats. Forty graft pairs were taken from rat tibias, and were frozen, defatted in chloroform-methanol, and dried. In addition, 1 graft of each pair was treated with 2% hydrogen peroxide, 2.5 Mrad irradiation, or by a Steri-Vac hospital ethylene oxide chamber. The grafts were placed in bone conduction chambers and implanted in rat tibias. Six weeks after implantation, the chambers were emptied, and the new bone ingrowth distance and scintimetric activity were measured. Ethylene oxide treatment impaired the new bone ingrowth distance by 68% and reduced the scintimetric activity by 51%. Another 10 defatted grafts, which had been ethylene oxide treated together with the grafts for implantation, were analyzed for levels of residual ethylene oxide, ethylene chlorohydrin, and ethylene glycol. All the measured residuals were below the detection limit of 20 parts per million, which was below the level recommended by the United States Food and Drug Administration. Ethylene oxide sterilization was more deleterious for bone allografts than expected.
Animals↗
[Otosclerosis: study of the postoperative course of hearing during the first 5 years and research of some prognostic factors. Apropos of a series of 67 cases].
Post-operative air conduction and bone conduction thresholds at 3 months, 1 year and 5 years after stapedectomy or stapedotomy in 67 patients were studied. Bone conduction thresholds improved in the first year postoperatively, then decreased progressively, less than in the non-operated ear but more than in a normal population. The air-bone gap was closed in 75% of the patients. The air-bone gap stayed at the same level during the studied period. Air conduction and bone conduction thresholds are better in the stapedotomy group than in the stapedectomy group only in the 4000 Hz frequency, and are similar for both groups in the 500-2000 Hz range.
Adult↗
[History of the tuning fork. II: Evolution of the classical experiments by Weber, Rinne and Schwabach].
BACKGROUND: Since the 17th centrury it was known that sounds could be perceived via air conduction and bone conduction and that this provided a means of differentiating between hearing disorders located in the middle ear and those located in the acoustic nerve. For a long time to come, however, there was no need for such a differential diagnosis. After the invention of the tuning fork in 1711 this instrument had soon become widely used in music, but it took well over 100 years until it was introduced into physiology and otology. FROM DIRECTIONAL HEARING TO WEBER'S TEST: J. B. Venturi, a physicist in Modena, Italy, in 1802 had shown that the perception of the direction from which a sound is coming is governed by the fact that one ear is hit by the sound more intensely than the other ear. C. T. Tourtual, a physician in Münster, Germany, demonstrated in 1827 that this also holds true for sound conducted via the skull bones. He used a watch as sound source. He found that occlusion of both ear canals would increase the sensation in both ears equally, but that occlusion of only one ear would increase the sensation only in the occluded ear, thus giving the impression that the sound were coming from that side. He was interested in a comparison between vision and audition, and he concluded that with regard to recognizing the direction of a sensory signal vision was superior to audition. In the same year 1827 C. Wheatstone, a physicist in London, investigating the mode of vibration of the tympanic membrane and using a tuning fork found the same phenomena as Tourtual and some more effects. E. H. Weber, an anatomist and physiologist in Leipzig, Germany, described the very same phenomena as Tourtual and Wheatstone once more in 1834. He wanted to prove that airborne sound is perceived by the vestibulum and the semicircular canals, bone conducted sound by the cochlea. None of these investigators was thinking of a clinical use of their findings and made no such suggestion. E. Schmalz, an otologist in Dresden, Germany, in 1845 introduced the tuning fork and the test later named after Weber into otology and explained in great detail all possibilities of a diagnostic evaluation of the test. His grand achievement, however, passed unnoticed at his time. THE RINNE TEST: A. Rinne, a physician in Göttingen, Germany. In 1855 described the test which later was named after him, in an elaborate treatise on the physiology of the ear. He wanted to demonstrate that in man and animals living in the air, as opposed to those living in water, the conduction of sound via the bones of the skull is just an unavoidable side effect of sound perception. He mentioned a clinical application of his test only in a footnote and obviously never used it himself in a systematic way. His test was made generally known by Lucae in Berlin only after 1880. The value of Weber's and Rinne's tuning fork tests was much disputed even at the turn of the century and only gradually became generally accepted.
Bone Conduction↗
Histologic changes on stapedial footplate in otosclerosis. Correlations between histologic activity and clinical findings.
OBJECTIVE: To quantify the relationship between the stage of histologic changes of the stapedial footplate in otosclerosis and the magnitude of preoperative hearing loss, tinnitus, vestibular disorder, and postoperative improvement of hearing. STUDY DESIGN: Retrospective case review. SETTING: Tertiary referral center. PATIENTS: The study included 97 patients (ears) (69 female and 28 male patients), with conductive or mixed hearing loss who were operated on for otosclerosis. The criterion for including a patient in the study was otosclerosis established by tympanoscopy and confirmed by histologic examination of a piece of the stapedial footplate. MAIN OUTCOME MEASURES: By the histologic features of the stapedial footplate fragments, the stage of the otosclerotic lesion was classified as spongiotic, fibrotic, or sclerotic. The patients were carefully matched for sex, age, duration of hearing impairment, presence of tinnitus, and vestibular symptoms. Preoperative and postoperative air-conduction and bone-conduction thresholds were calculated as an average of four frequencies (0.5, 1, 2, and 4 kHz). Analysis was subsequently carried out on the preoperative and postoperative air-bone gap and bone-conduction threshold improvement. RESULTS: With regard to the histologic stage of otosclerotic lesions, tinnitus and vestibular disorders were present more frequently in patients with the sclerotic type of lesion. The type of otosclerotic lesion had no significant influence on the mean preoperative air-conduction threshold, bone-conduction threshold, and air-bone gap or on postoperative air-conduction threshold and bone-conduction threshold, but the postoperative air-bone gap was higher in patients with the fibrotic type of otosclerotic lesion and was highest in patients with the spongiotic type of otosclerotic lesion (p < 0.01). CONCLUSIONS: Tinnitus, vestibular disorders, and better postoperative closure of the air-bone gap are present more frequently in patients with a sclerotic type of otosclerotic lesion on the stapedial footplate.
Adult↗
Sensorineural hearing loss in chronic otitis media.
OBJECTIVE: To determine whether chronic suppurative otitis media may cause sensorineural hearing loss. METHODS: The files of 121 patients with unilateral chronic suppurative otitis media were reviewed in a retrospective study. Air conduction and bone conduction threshold averages were calculated over the speech frequencies (500 Hz, 1,000 Hz, and 2,000 Hz). Thresholds at 4 kHz were examined separately but in a similar way. Multiple linear regression models were used to clarify the relationships between sensorineural hearing loss and chronic otitis media. RESULTS: Chronic suppurative otitis media was seen to be associated with sensorineural hearing loss. When age and normal side were corrected for, pure-tone threshold and bone conduction threshold at either the speech frequencies or at 4 kHz increased gradually according to the duration of the chronic suppurative otitis media. The threshold shift was more accentuated as age increased. The sensorineural hearing loss at 4 kHz seemed to be higher than that at the speech frequencies. CONCLUSIONS: The inner ear is vulnerable against chronic suppurative otitis media. Older age increases this vulnerability. The proximity of the sensory cells to the potential source of harm (inflamed middle ear) may mean higher exposure, as reflected by the fact that sensory cells processing higher frequencies are more seriously damaged.
Adolescent↗
The effect of stapes surgery on high frequency hearing in patients with otosclerosis.
OBJECTIVE: To assess the effect of stapedectomy on high frequency hearing. STUDY DESIGN: A retrospective, one-group, pretest-posttest case review was performed of the audiometric data of patients who underwent stapedectomy at a tertiary referral center. PATIENTS: Thirty-eight patients (40 ears) with primary uncomplicated surgery were selected. Twenty-two of the patients were older than 40 years. Preoperative and postoperative audiograms were analyzed. RESULTS: Preoperative and postoperative audiograms exhibited a down-sloping configuration toward the high frequencies. Surgery resulted in a significant improvement (p < 0.05) from 500 to 4000 Hz in air conduction and 500 to 2000 Hz in bone conduction. Analysis of variance showed that age had no bearing on preoperative audiometric results (p < 0.05) for air conduction, bone conduction, and the air bone gap. Postoperatively, younger patients' 4000 to 8000 Hz (air conduction) and 4000 Hz (bone conduction) were better than those of the older patients (p < 0.05), but the high frequency range was still poorer than age-matched controls in the younger patients. CONCLUSION: Stapedectomy resulted in significant closure of the air bone gap between 500 to 4000 Hz, but failed to influence hearing above 4000 Hz. Age appears to be an important variable; poorer results in the high frequency range were seen in the older patients who underwent stapes surgery. These findings, together with the residual postoperative hearing loss in the high frequency range in young patients, may reflect disease-specific injury resulting from cochlear otosclerosis.
Adult↗
[History of the tuning fork. III: On the way to quantitative pure-tone measurement. Pictures from the history of otorhinolaryngology, represented by instruments from the collection of the Ingolstadt German Medical History Museum].
BACKGROUND: Weber's and Rinne's tuning-fork tests were for a long time considered unreliable, as they often seemed to yield inconsistent results. The sources of error were manifold and lay in the fields of physics, physiology, pathophysiology, and psychology. When the problems came to be understood, more sophisticated instruments and techniques were developed. TECHNICAL IMPROVEMENTS IN TUNING FORKS: The prongs of the tuning fork were fitted with clamps to deaden overtones when it was put into vibration (Politzer 1870). By shifting the clamps along the prongs the tone of the tuning fork could be varied in a range up to one octave (Könlg 1878). A knob of hom or metal was fixed to the end of the shaft to ensure a good coupling to the skull when testing bone conduction (Lucae 1886). A small hammer fixed to the shaft and driven by a spring would activate the tuning fork with reproducible strength (Lucae 1899). A wedge-shaped figure drawn on the lateral surface of the clamps would allow one to optically control the amplitude of vibration (Gradenigo 1899). METHODS FOR QUANTIFICATION OF MEASURING HEARING ACUITY: The time during which a patient hears the tuning fork after it has been struck as compared to that of a normal hearing subject was measured as parameter of hearing acutiy (v. Conta 1864). A number of tuning forks at intervals of one octave each were assembled in sets to cover the whole frequency range of hearing. The most sophisticated example of these sets was the Bezold-Edelmann continuous tone series (1894). It comprised ten tuning forks with sliding clamps, two pipes of the organ type, and a Galton whistle. With this instrumentation it was possible to test the whole range of hearing. GRAPHIC PRESENTATION OF QUANTITATIVE RESULTS OF HEARING TESTING: The results of testing the hearing via air conduction and bone conduction measured in duration and calculated as percentage of normal hearing were presented in charts (Hartmann 1885, Gradenigo 1893) which can be considered precursors of modern audiograms. The evolution of these instruments and methods is described in detail and illustrated by exhibits from the museum.
Audiometry, Pure-Tone↗
A re-examination of the Carhart effect.
It is well established that in individuals with a conductive hearing loss the bone conduction thresholds do not directly indicate cochlear function, and are artificially depressed as witnessed by their improvement following successful reconstructive surgery. This depression, which we define as the 'Carhart effect' is due to changes in the middle and external ear contributions to bone conduction. Published figures for the Carhart effect, inferred from pre- and post-operative bone conduction thresholds vary considerably but the discrepancies are markedly reduced when the appropriate selection criteria are used. However, theoretical considerations would suggest that values based on a comparison of bone conduction before and after surgery underestimate the size of the Carhart effect. This is confirmed at least at low frequencies, by a series of experiments on six normal individuals in whom an artificial conductive hearing loss was created by increasing the ear canal pressure. The change in bone conduction threshold was 5 dB at 250 Hz, and 15 dB at 500 Hz, changes greater than those estimated from surgical data.
Auditory Threshold↗
Stapedotomy with microdrill or carbon dioxide laser: influence on inner ear function.
OBJECTIVES: A prospective randomized audiological analysis of 336 otosclerosis operations was conducted to compare the evolution of bone conduction thresholds after primary stapedotomy with two different techniques to open the footplate: microdrill and carbon dioxide laser stapedotomy. METHODS: To monitor the inner ear function, we compared the preoperative bone conduction thresholds with the postoperative levels at day 2, week 2, week 6, and month 6. Evolution of the bone conduction was compared for the two studied groups (laser versus microdrill). RESULTS: An average bone conduction loss of 1.8 dB was measured at day 2 for the middle frequencies (0.5, 1, and 2 kHz). At 4 kHz, a bone conduction loss of 7 dB was found. The bone conduction thresholds measured in the first and second months after surgery showed a gradual recovery with overclosure as the end result. CONCLUSIONS: Our results confirm the transient depression of inner ear function in the immediate postoperative period, with recovery within the first weeks after surgery. In the studied population, no statistically significant difference was found between the two techniques that were used to make the calibrated hole (laser versus microdrill). These results demonstrate that both techniques possess the same early effect regarding inner ear function. The authors hypothesize that an early inflammatory reaction could be the cause of the transient bone conduction shift.
Adolescent↗
Cartilage induction by controlled mechanical stimulation in vivo.
To study mechanical control of tissue differentiation, we designed a new version of the previously described bone conduction chamber. The bone conduction chamber consists of a cylindrical titanium chamber for implantation in the rat tibia. It has tissue ingrowth openings at one end, located subcortically, and the other end protrudes into the subcutis. The newly developed load chamber has a mobile piston so that an external compressive load can be transferred to the tissue within the chamber. Sprague-Dawley rats had a regular bone conduction chamber implanted in one tibia and a load chamber implanted in the other. Mesenchymal tissue was allowed to grow into the chamber for 3 weeks before the mechanical loading was started. Thereafter, twice a day, 20 cycles of compressive load were applied with a frequency of 0.17 Hz to the load chamber. This was estimated to produce a compressive hydrostatic stress of 2 MPa. The chambers, harvested after 7 weeks of loading, all contained newly formed bone. The bone ingrowth distance into the chamber was decreased in the loaded specimens compared with the contralateral unloaded controls (p = 0.01). Instead, cartilage was found in the loaded chambers next to the piston. Beneath the cartilage was a dense bone plate under which a marrow cavity had formed. No cartilage was found in the unloaded controls, but the architecture of the bone and marrow cavity was similar to that of the loaded specimens. We conclude that this model allows load to be transmitted onto the ingrowing tissue and that the load parameters used cause this tissue to differentiate into cartilage close to the piston.
Animals↗
[Long-term results of stapes surgery--over 1000 patients].
Authors present audiometric results of 1200 patients with otosclerosis post stapedotomy. Air-conduction, bone-conduction and air-bone gap was measured prior the surgery and 12 months post stapedotomy for frequencies 0.5, 1.0, 2.0 and 3.0 kHz. In the analysed group of 1200 patients a postoperative air-bone gap 0-10 and 11-20 dB was obtained in 93.7% patients. The result of stapedotomy in reference to tinnitus based on the patients' subjective opinion showed that 78.0% patients were either free from tinnitus or tinnitus was subjectively decreased. Authors stress that some anatomical abnormalities in the tympanic cavity might influence on the result of stapes surgery.
Audiometry, Pure-Tone↗
Far-advanced otosclerosis.
Far-advanced otosclerosis (FAO) is an uncommon diagnosis. Hearing levels in patients with FAO may range from profound loss, by air conduction and fragmentary bone conduction thresholds, to no measurable air or bone conduction thresholds. Thus, FAO may be difficult to distinguish from a sensorineural hearing loss. This report presents the results of surgery in 73 ears with FAO, 77 percent of which had improvement in air conduction thresholds of greater than 20 dB. Discrimination was improved by more than 15 percent in 54 percent of cases, and 75 percent realized improvement in use of a hearing aid. There was no evidence that success was related to preoperative hearing. The surgical results of a subgroup of 14 patients having bilateral FAO were also analyzed. For all 14, similar surgical outcomes were achieved in both the initial and the contralateral ear, with six successes bilaterally and eight failures bilaterally. Although far advanced otosclerosis is uncommon and difficult to diagnose, surgery is worthwhile.
Acoustic Stimulation↗
The auditory steady-state response: clinical observations and applications in infants and children.
Two studies illustrate the use of the auditory steady-state response (ASSR) in the pediatric clinical audiology setting. A protocol for estimating bone-conduction thresholds from ASSR was developed. Bone-conducted narrow-band noise was used to mask the ASSR for a 1.0-kHz modulated tone. The amount of bone-conducted noise needed to mask the ASSR may distinguish between infants and children with conductive hearing losses and those with sensory losses. The amount of bone-conducted noise may also be used to estimate bone-conduction thresholds; however, the accuracy of this technique needs verification with behavioral methods to determine thresholds for bone-conducted pure tones in infants. When ASSR tests are used as part of the diagnostic evaluation for infants and children at risk for hearing loss, the results yield information about the audiometric contour and residual hearing, which aid in treatment and habilitation decisions.
Acoustic Impedance Tests↗
The pure-tone hearing thresholds of otologically healthy 14-year-old children.
The mean pure-tone air conduction (AC) and bone conduction (BC) hearing thresholds (HT) of 534 randomly selected, caucasian, white, urban children with normal otoscopy, otomicroscopy and impedance audiometry, i.e. normal middle ear function, are presented here. Children with pathological middle ear findings or abnormal impedance audiometry were excluded. The average age was 13.8 years, SD 0.5, at the date of examination. The mean air conduction thresholds varied between 0.6 dB at 1 kHz and 9.9 dB at 6 kHz, and the bone conduction thresholds varied between -1.1 dB at 0.5 kHz and 1.1 dB at 4 kHz. The pure-tone average (PTA) (the average of AC hearing thresholds of 0.5, 1 and 2 kHz) of all ears was 1.5 dB. Ninety to ninety-eight per cent of pure-tone AC hearing thresholds at frequencies of 0.5-4 kHz were between -5 dB and 10 dB. The distributions are presented and compared.
Adolescent↗