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PubMed1986

Methods of measuring the attenuation of hearing protection devices.

The published literature describing three real-ear-attenuation-at-threshold (REAT), nine above-threshold, and four objective methods of measuring hearing protector attenuation is reviewed and analyzed with regard to the accuracy, practicality, and applicability of the various techniques. The analysis indicates that the REAT method is one of the most accurate available techniques since it assesses all of the sound paths to the occluded ear and, depending upon the experimenter's intention, can reflect actual in-use attenuation as well. An artifact in the REAT paradigm is that masking in the occluded ear due to physiological noise can spuriously increase low-frequency (less than or equal to 500 Hz) attenuation, although the error never exceeds approximately 5 dB, regardless of the device, except below 125 Hz. Since the preponderance of available data indicates that attenuation is independent of sound level for intentionally linear protectors, the use of above-threshold procedures to evaluate attenuation is not a necessity. An exception exists in the case of impulsive noises, for which the existing data are not unequivocal with regard to hearing protector response characteristics. Two of the objective methods (acoustical test fixture and microphone in real ear) are considerable time savers. All objective procedures are lacking in their ability to accurately determine the importance of the flanking bone-conduction paths, although some authors have incorporated this feature as a post-measurement correction. The microphone in real-ear approach is suggested to be one of the most promising for future standardization efforts and research purposes, and the acoustical test fixture technique is recommended (with certain reservations) for quality control and buyer acceptance testing.

Acoustic Stimulation↗
PubMed1989

An acoustic head simulator for hearing protector evaluation. I: Design and construction.

As an alternative to subjective methods, an acoustic head simulator was constructed for hearing protector evaluation. The primary purpose of the device is for hearing protector testing and research under high-level steady-state and impulse noise environments. The design is based on the KEMAR manikin and therefore approximates the physical dimensions and the acoustical eardrum impedance of the median human adult. The head simulator includes a mechanical reproduction of the human circumaural and intraaural tissues with a silicone rubber material. A compliant head-neck system was constructed to approximate the vibrational characteristics of the human head in a sound field in order to simulate the inertia effect of earmuffs. The bone-conducted sounds are not mechanically reproduced in the design. Applications for the device are reported in a companion article [C. Giguère and H. Kunov, J. Acoust. Soc. Am. 85, 1197-1205 (1989)].

Auditory Threshold↗
PubMed1983

Rib fractures in coronary bypass patients: radionuclide detection.

Sternal retraction can cause the first rib to be fractured posteriorly, injuring the brachial plexus. The authors conducted bone scans of 24 consecutive open-heart surgery patients and found an unexpectedly high number of rib fractures which in all but one case had not been seen on the chest radiograph. Bone scans are recommended whenever there is unexplained non-incisional pain in a patient who has undergone sternal retraction.

Coronary Artery Bypass↗
PubMed2006

Is small-fenestra stapedotomy a safer outpatient procedure than total stapedectomy?

We compared two stapedoplasty techniques to evaluate whether one technique is safer than the other as an outpatient procedure and to demonstrate possible reasons for outpatient failures. We performed a retrospective study of patient records of 94 operated adult patients who were all initially scheduled for outpatient surgery for otosclerosis (47 total stapedectomies and 47 small-fenestra stapedotomies). Six patients (13%) with stapedectomy and 1 patient (2%) with stapedotomy had to stay overnight at the hospital due to postoperative vertigo and nausea. The number of outpatient failures was statistically significantly different between the stapedoplasty techniques (p = 0.05). Five patients (11%) with stapedectomy and 2 patients (4%) with stapedotomy had a drop in bone conduction threshold between 5 and 8 dB pre- to postoperatively (n.s.). The short-term hearing improvement did not differ statistically significantly between the techniques when compared to the preoperative values. Small-fenestra stapedotomy is the safer procedure to be performed as outpatient setting than total stapedectomy.

Adolescent↗
PubMed2006

Normative auditory brainstem response data for hearing threshold in the rabbit.

In an experimental study, we determined the physiological hearing threshold of the rabbit in order to use these data as normative values for further experimental investigations. The aim was to use different acoustic stimuli (click and tone-pip stimuli) with different frequency spectra for air and bone conduction (BC) in order to obtain further information about the optimal form of stimulus when recording auditory evoked potentials in the rabbit. For the investigation, we used 46 female New Zealand rabbits weighing 3.2-4.4 kg and aged 6 months. The equipment used to record brainstem auditory evoked potentials was the Nicolet Viking IV P System (Nicolet Biomedical, Inc.). In accordance with the experimental set-up, the measurements took place under intubation anesthesia, with a total of four repeat measurements performed on each ear at different times. Tone-pip and click stimuli with varying intensities of stimulus, transmitted via air conduction and BC, were applied. The I-IV waves proved the most stable for both stimulus modalities. They were registrable in 98.7% of cases, whereas only 30.2% of the V waves could be recorded. Values averaged from all measurements made throughout the study yielded a potential threshold of 34.8 dB peak equivalent (p.e.) SPL for the click stimulus, 13.8 dB p.e. SPL for the tone-pip stimulus at 8 kHz and 34.2 dB p.e. SPL for the click stimulus transmitted via BC. With regard to latencies, the results indicated a good reproducibility through different stimuli with acceptable standard deviations. The values for physiological hearing threshold obtained here can serve as normative data in subsequent experimental animal studies.

Acoustic Stimulation↗
PubMed1987

The partially implantable middle ear implant, case reports.

The partially implantable middle ear implant (MEI) is clinically useful for bilateral deafness when it is applied to the mixed deafness with a bone conduction threshold of 20-40 dB. Two out of five successful cases are reported. It should be noted that 1.5 years have passed without changes for the first successful implantation. The next step for application of the MEI to more cases is discussed.

Adolescent↗
PubMedDate not supplied

Stapedectomy. Postmortem findings.

Histological studies were made of 16 temporal bones of 13 subjects who had stapedectomy operations. Photographs of the prostheses in situ are a special feature of the studies. It was found that prostheses which overlap the margins of the oval window cause incomplete closure of the air-bone gaps. Fibrous adhesions were a common consequence of trauma to the mucous membrane of the middle ear. Gelfoam implantation promotes the formation of thin oval window membranes which tend to bulge out of the oval window. Most incudes show small areas of cortical bone resorption. In at least half the cases the surgical technique of stapedectomy, as judged from these studies, was less than ideal. Surgeons who perform stapedectomy should be cognizant of the relevant surgical pathology and adopt methods which will optimize functional results and minimize complications.

Adult↗
PubMedDate not supplied

Results after treatment of otitis media with effusion.

Otitis media with effusion will be observed in every fifth child admitted for adenoid surgery; in children with cleft palates the incidence is 50%. With adenoidectomy alone, normal hearing can be restored in 50% and improved in further 25% of the patients. Over a 12-year period 1,683 patients with otitis media with effusion were treated with adenoidectomy and with insertion of tympanostomy tubes in those cases where adenoidectomy proved to be ineffective. Since the tubes only substitute tubal function, recurrences have to be expected in more than 30% after spontaneous extrusion of the tubes. Of all recurrences, 93% occur within two years after tube insertion. With thorough follow-up and repeated insertion of tubes, deterioration of the middle-ear can be avoided and hearing kept normal. Impaired bone conduction does not reflect inner ear damage, but will improve with ventilation of the middle ear. Infections occur in 15% (5% postoperatively, 10% later); persistent perforations in 2.5% and cholesteatoma in 0.9%.

Adenoidectomy↗
PubMed1990

Bilateral semicircular canal aplasia with near-normal cochlear development. Two case reports.

Congenital malformations of the vestibular labyrinth (pars superior) are rare. We present two patients with computed tomographic findings of bilateral semicircular canal aplasia with normal or near-normal cochleas. Initial bone conduction thresholds were within normal limits, although both patients had significant conductive hearing losses due to congenital middle ear malformations. Bithermal caloric responses were absent in both. To our knowledge these are the first reports of vestibular aplasia concomitant with normal or near-normal cochlear development. These findings conflict with conventional hypotheses that state that inner ear malformations result from arrested development during the normal stages of inner ear embryogenesis.

Adult↗
PubMed1999

Radiation-induced hearing impairment in patients treated for malignant parotid tumor.

Radiation-induced hearing loss was evaluated in 21 patients with unilateral malignant parotid tumors treated with surgery and radiotherapy. The contralateral ear was used as a control. Eight patients (38%) were found to have a reduction in static compliance of the tympanic membrane (type B tympanogram) in the irradiated ear. By audiometry, significant hearing loss was found in 9 patients (43%). These hearing losses were mainly sensorineural, as shown by a similar reduction in both air and bone conduction, although mixed-type hearing loss existed in some patients. A statistically significant difference in incidence of 67% versus 0% (p = .0085) was noted for patients with a cochlear dose of greater than or equal to 60 Gy, in comparison to those receiving doses of less than 60 Gy. A type B tympanogram was also found to be a prognostic factor for significant sensorineural hearing loss. Patients with type B tympanograms had a much higher incidence of significant sensorineural hearing loss than those with type A tympanograms (88% versus 15%, p = .02). This study clearly shows that radiotherapy can induce significant hearing impairment, especially when the cochlear doses are higher than 60 Gy.

Acoustic Impedance Tests↗
PubMedDate not supplied

The case for small fenestra stapedectomy.

Eight hundred stapedectomies were analyzed to evaluate the long-term results with four prostheses. It was concluded that limitation of fenestra size played a most important part in the outcome of stapedectomy, especially in regard to the preservation of high-frequency bone conduction response over prolonged periods. Other advantages deriving from small fenestra stapedectomy included significantly fewer fistulae and severe sensorineural losses.

Fistula↗
PubMed1985

Cochlear hearing loss in tympanoplasty.

In tympanoplasty, trauma to the cochlea is usually caused by the transmission of vibration induced during the removal of cholesteatoma, granulation tissue, and tympanosclerosis surrounding the ossicular chain. In 100 sequential cases 20 showed evidence of cochlear trauma. Hearing was recovered in 10 of these cases during the immediate postoperative period. In nine the hearing was partially recovered but remained below the preoperative bone-conduction level, and in one there was a total cochlear hearing loss. When the stapes footplate was fractured or dislocated and a perilymphatic fistula developed, profound cochlear hearing loss occurred. This complication usually can be avoided by inspection of the round and oval windows under high magnification and by tissue grafts over the fistula. An unanticipated pathologic fistula of the semicircular canals is another common source of major cochlear damage. Despite all precautions and sometimes without apparent cause, a total cochlear hearing loss may result after a tympanoplasty. Although this is rare, as evidenced by the fact that there were only 15 cases in some 1000 tympanoplasties, before surgery the surgeon must inform the patient of the risks involved.

Cholesteatoma↗
PubMed1989

Natural history vs. surgery for Menière's disease.

Menière's disease has an episodic course, and certain patients undergo spontaneous remission of their vertigo. A retrospective study of patients treated from 1974 to 1983 was undertaken to evaluate the long-term outcome of patients with Menière's disease for whom surgery was recommended, comparing those who had a surgical procedure with a similar group of patients who declined surgery. The surgical procedures performed were endolymphatic subarachnoid shunt (ELS), retrolabyrinthine vestibular neurectomy (RVN), middle fossa vestibular neurectomy (MFVN), and transmeatal cochleo-vestibular neurectomy (CVN). We used a questionnaire, made up according to the 1985 American Academy of Otolaryngology (AAO) criteria, for reporting results for Menière's disease treatment, and compared patients who were offered surgery but declined (N = 50) with those who underwent surgery (N = 83). The data were analyzed statistically. Initial evaluation, which included air and bone conduction audiometry, speech discrimination, electronystagmography (ENG), frequency of vertigo attacks per month, and disability, showed both groups to be comparable at the outset. Of the non-operated group 57% had complete control of vertigo at 2 years; 71% had complete control after an average of 8.3 years. After an ELS, 40% of patients had complete control of vertigo after 2 years; 70% had complete control after an average of 8.7 years. After a neurectomy (RVN or CVN), 93% had complete control of vertigo (average followup, 4.4 years). These results indicate statistically that the ELS procedure does not alter the long-term natural course of vertigo control in Menière's disease, whereas both the RVN and CVN significantly improve the patient's chance of being permanently free of vertigo attacks.

Aged↗
PubMed1989

The fate of the non-operated ear in otosclerosis.

Records of 300 consecutive patients who had only one ear operated on by stapedectomy and who received long-term followup were studied. These cases came from 3036 stapedectomy operations performed between January 1961 and April 1969. In general, the two ears behaved the same: if a "flat" sensorineural loss occurred in one ear, it was likely to develop in the other. Similarly, if one ear developed a high-tone loss, the other would do likewise. With the exception of acute fistula, there is no suggestion that the operation of stapedectomy predisposes an ear to late sensorineural problems. Patients with bone-conduction thresholds that are depressed at all frequencies when first examined should be advised that progressive sensorineural hearing loss may occur later in both ears. Accordingly, the benefit gained by stapedectomy may ultimately need to be supplemented by hearing aids. This study also revealed that a patient with clinical conductive otosclerosis in only one ear at first presentation had only a 50% chance of long-term benefit from stapedectomy.

Female↗
PubMed1990

Surgical management of cholesteatoma in an only hearing ear.

The patient with a cholesteatoma in an only hearing ear presents a management dilemma: how best to treat the patient to minimize the chances of developing a severe hearing loss in that ear. Twelve patients managed surgically for cholesteatoma in their only hearing ear are reviewed. The location and extent of the cholesteatoma, the type of operation performed, and postoperative hearing results are presented. Eleven of the 12 patients maintained their bone-conducted speech reception threshold to within 5 dB of the preoperative level during follow-up periods of 2 months to 4 years. Recommendations are made regarding preoperative evaluation, perioperative use of antibiotics and steroids, operative planning, ossicular reconstruction, and postoperative care. Special attention is given to the evaluation and management of the ear that has a fistula eroding into the cochlea and semicircular canals, both when suspected from preoperative imaging studies and when discovered intraoperatively.

Cholesteatoma↗
PubMed2006

Sensorineural hearing loss after radiotherapy and chemoradiotherapy: a single, blinded, randomized study.

PURPOSE: The synergistic ototoxicity of radiation and cisplatin (CDDP) has not been adequately studied. This study investigated whether the use of concurrent and postradiotherapy CDDP in patients with nasopharyngeal carcinoma (NPC) resulted in a difference in postradiotherapy sensorineural hearing when compared with the use of radiotherapy alone. PATIENTS AND METHODS: Newly diagnosed patients were randomly assigned to the radiotherapy or chemoradiotherapy groups. Bone conduction hearing thresholds were performed before treatment and at 1 week, 6 months, 1 year, and 2 years after completion of radiotherapy. Statistical analysis was performed using the Mann-Whitney U test. RESULTS: Hearing thresholds averaged over 0.5, 1, and 2 kHz were found to be poorer in the chemoradiotherapy group (58 patients) compared with the radiotherapy group (57 patients) at 1 year (P = .001) and 2 years (P = .03) after radiotherapy. Hearing thresholds at 4 kHz were significantly worse for patients in the chemoradiotherapy arm at all of the postradiotherapy time points studied and were more severely affected than the thresholds at lower speech frequencies. In the radiotherapy group, deterioration of median hearing thresholds, which occurred in the immediate post-treatment period, improved within the first year but deteriorated again at 2 years. In the chemoradiotherapy group, median hearing threshold deterioration, which started immediately after radiotherapy, stabilized by 1 year. CONCLUSION: Patients with NPC who received radiotherapy and concurrent/adjuvant chemotherapy using CDDP experienced greater sensorineural hearing loss compared with patients treated with radiotherapy alone, especially to high-frequency sounds in the speech range. Normal inner ear tissue tolerance, which was once defined only for radiotherapy patients alone, should be redefined in chemoradiotherapy patients.

Adolescent↗
PubMedDate not supplied

Alternative field methods for measuring hearing protector performance.

In comparison with the mandatory noise reduction rating (NRR) testing of every hearing protector sold in the United States, real-world tests of hearing protector attenuation are scarce. This study evaluated data from three potential field-test methods as compared with the subject-fit data from Method B of ANSI S12.6-1997 for the E.A.R(R) Express trade mark Pod Plug trade mark. The new field-test methods were the FitCheck headphone (FCH) method, FitCheck in sound field (FCSF) method, and bone-conduction loudness balance (BCLB) method, all of which can be administered in small single-person audiometric booths such as are commonly found in industry. Twenty normal-hearing and audiometrically competent subjects naive to hearing protector use were tested with the laboratory and the three field-test methods in a repeated-measures design. Repeated-measures models with structured covariance matrices were used to analyze the data. Significant effects were found for method, frequency, and first-order frequency-by-gender and frequency-by-method interactions. These effects and interactions were expected given the different psychophysical tasks. The FCSF and BCLB methods provided attenuations that were not significantly different from those found with Method B. Although the attenuations measured for the FCH method were statistically different (greater) than the attenuations from the other methods, the differences were within the magnitude of acceptable test-retest audiometric variability. The results suggest that the FCH and FCSF methods were both feasible and reliable methods for field testing. The FCH method is limited to testing earplugs, and the FCSF requires additional equipment to outfit the test booth, but could be used for testing all types of protectors.

Adolescent↗