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PubMedDate not supplied

Occupational safety: effects of workplace radiofrequencies on hearing function.

BACKGROUND: The effects of radio frequency (RF) and microwave radiation on humans have been the subject of continuous investigation. Clinical investigations related to occupational RF/microwave exposure have been reported by investigators (1). Since one of the major groups occupationally exposed to RF and microwave radiation includes those working in radio broadcasting and TV transmitter stations, this study investigates whether RF affects auditory systems of people exposed to RF. METHODS: The study is carried out with people working in radio broadcasting stations and living in employee residential houses close to the broadcasting stations. All subjects in the control group were similar in age, work regime, socioeconomic status, and lack of experience in working with RF sources. Brainstem Evoked Response Audiometer (BERA) and Pure Tone Audiometry (PTA) were used to measure the effects of RF under investigation on hearing functions of the subjects. In BERA measurements, I-III, III-V and I-V interpeak latencies were evaluated. In pure tone audiometric measurements, 250 Hz, 500 Hz, 1000 Hz, 2000 Hz, 4000 Hz and 8000 Hz frequencies of hearing threshold were measured in subjects of experimental and control groups. Interpeak latencies and bone conduction hearing thresholds of subjects in the experimental group were compared with those of the control group. RESULTS: BERA results showed that I-III, I-V and III-V interpeak latencies of people occupationally exposed to RF were not higher than subjects in control groups (p>0.05). Results of BERA indicated no statistically significant differences between exposure and control subjects. In audiometric evaluation, hearing threshold of people occupationally exposed to RF were found higher than the control group subjects for frequencies of 4000 Hz and 8000 Hz in terms of bone and air conduction of right and left ear (p < 0.01). CONCLUSIONS: The results of traditional audiometer indicated that RF promotes sensorineural hearing loss and affects cochlea parts related to 4000 Hz and 8000 Hz. These findings may have immediate implications and considerations for workplace safety in order to provide an occupationally safe environment to employees working in such settings.

Audiometry, Pure-Tone↗
PubMed1998

A review of 308 cases of revision stapedectomy.

OBJECTIVE/HYPOTHESIS: Identify causes of primary and revision stapedectomy failure in 308 patients, assess whether these are different based on source of initial surgery, and evaluate hearing results in revision stapedectomy to improve outcome. STUDY DESIGN: Retrospective, nonrandomized chart review of patients undergoing revision stapedectomy in a referral otology practice in a large metropolitan region. MATERIALS AND METHODS: Intraoperative findings, preoperative and postoperative revision stapedectomy air and bone conduction pure-tone averages, speech discrimination scores, postoperative air-bone gaps, complications, and repeated revisions were noted in 308 patients. RESULTS: Leading causes of primary stapedectomy failure included dislocated prosthesis (24.4%), inadequate prosthesis length (14%), long process resorption (14%), and fibrous adhesions (13.6%). Revision stapedectomy air-bone gaps were less than 10 dB in 80% and greater than 30 dB in 6.8% of cases. Increased sensorineural hearing loss occurred in 0.8% of revision stapedectomy cases. Five of seven cases of vertigo associated with primary stapedectomy resolved after revision surgery. CONCLUSION: Revision stapedectomy by experienced surgeons is highly effective in attaining successful air-bone gap closure in 80% and improved closure in 84.8% of operative cases. Risk of vertigo and/or sensorineural hearing loss was not any higher in this patient population when compared with reports of primary stapedectomy.

Adult↗
PubMed1993

The effects of etidronate disodium on progressive hearing loss from otosclerosis.

A 2-year prospective double-blind study was performed to evaluate the role of etidronate disodium for the treatment of progressive hearing loss in patients with otosclerosis. A pulsed dosage regimen was used during the 2-year period and the patients were followed up with otologic and audiometric examinations. Although statistically significant differences were not achieved between the study and control groups, the study did reveal a trend toward stabilization or improvement in air conduction thresholds in some frequencies (1000 and 4000 Hz) and in bone conduction thresholds at other frequencies (500, 1000, and 2000 Hz). The incidence of adverse side effects was similar in the treatment and control groups. Although no definite conclusions can be drawn from this pilot study, the findings provide encouragement for performing a larger and longer-term study.

Adult↗
PubMed1984

A critical comparison of allogeneic bone marrow transplantation and conventional chemotherapy as treatment for acute nonlymphocytic leukemia.

Published data from two centers conducting bone marrow transplantation on patients with acute nonlymphocytic leukemia in first remission were pooled and compared with results from an Eastern Cooperative Oncology Group (ECOG) study in which patients were treated with conventional chemotherapy. A series of adjustments were made to the ECOG sample to account for selection factors that restrict access of patients to transplantation. The transplant sample exhibits considerably higher disease-free survival when compared to the adjusted ECOG series (53% versus 21% at three years). The transplant series is somewhat younger than the ECOG series (median, 24 years versus 28 years). The impact of age on the disease-free survival results is difficult to assess because of the relatively small samples in the different age groups. However, by defining a suitable control group, methodology for making a critical comparison between the two modalities is presented which, if applied to larger samples of patients, should help to resolve the issue. In the absence of data from a large, prospective randomized study, a critical retrospective comparison of available data is essential in the assessment of treatment options.

Acute Disease↗
PubMed1998

Tympanoscopy to increase the accuracy of diagnosis in conductive hearing loss.

The diagnosis of conductive hearing loss is usually based on audiological methods and radiology. The aim of our study was to show that there is a useful additive method to clarify the findings of diseases with conductive hearing loss. Patients (151 ears) with conductive hearing loss were examined using several methods: otomicroscopy, air- and bone-conduction threshold,pure tone average, speech threshold, speech discrimination, tympanometry and stapedial reflex and tympanoscopy. The management of the patients changed in 17 per cent of cases due to tympanoscopy. In a group with normal tympanic membrane the movement of the stapes during endoscopy was compared to stapedial reflex. Stiff stapes were found more often than an abnormal stapedial reflex. Middle ear endoscopy can increase the accuracy of diagnosis of conductive hearing loss thus enhancing decision making in the case of the patient.

Adolescent↗
PubMedDate not supplied

Percutaneous titanium implantation in the skull for the bone-anchored hearing aid.

In the 1980s, a new type of bone conduction hearing aid was developed in Göteborg, Sweden. With this new bone-anchored hearing aid (BAHA) system, sound waves are transmitted directly to the skull by means of a titanium screw implanted into the skull. The advantages and disadvantages of the conventional hearing aid and the BAHA are described here. In the 25 patients presented, all the percutaneous implants remained firmly anchored in the skull. One screw was lost through trauma. The scores on the speech recognition-in-noise and the speech recognition-in-quiet tests were significantly higher in 64% and 32% of the patients with a BAHA, respectively.

Adolescent↗
PubMed2003

Biomimetic nano-apatite coating capable of promoting bone ingrowth.

Nano-apatite coating closely mimicking bone mineral was grown directly on titanium soaked in an aqueous solution containing all major inorganic components present in the body, mainly, HCO3(-), Ca(2+), HPO4(2-), and Mg(2+) ions. The removal of HCO3(-) ions from the solution in the form of CO2 resulted in the increase of solution pH. As a consequence of this reaction, the nano-apatite coating was formed on the surface of titanium with composition and structure equivalent to those of bone mineral. The biomimetic nano-apatite was demonstrated to be capable of conducting bone formation and promoting direct bone apposition. This bioactive coating also affected the behavior of human osteoblasts as indicated by their morphologies observed in cell culture study.

Alloys↗
PubMed2005

[Exemplary classification of otolaryngologic data using the Kohonen artificial neural network].

An exemplary classification of otolaryngological data with use of the Kohonen artificial neural network is presented along with an evaluation of grouping effectiveness. The study was based on 220 patients with otosclerosis, including 184 women and 36 men, aged 16-68, operated at the Otosurgery Department, Medical University of Lodz in 1984-1992. The neural network distinguished 3 clusters considerably differing in air and bone conduction preoperatively and as a result in the values of postoperative air-bone gap. The effectiveness of classification was also exhibited in congruent with previous knowledge differences between clusters in many other variables not presented to the neural network.

Adolescent↗
PubMed2006

[Advance in management of skeletal trauma of the extremities].

OBJECTIVE: To investigate the advance in the management of skeletal trauma of the extremities. METHODS: The literature at home and abroad was reviewed, and the research findigs with clinical experience in the therapeutic methods for fracture of the extremities were summarized. RESULTS: The concept on fracture management was renewed, the minimally invasive surgery (MIS) was developed and popularized, the implantation was improved, the navigation technique with computer-assisted surgery was applied, and the tissue engineering was developed. The fracture management was changed from tubular bone, the boanatomical reduction with absolutely rigid fixation to the biological osteosynthesis with protection of the fracture environment. The minimally invasive surgical techniques included the minimally invasive plate osteosynthesis, intramedullary nailing, external fixation, arthroscopic surgery, and computer-assisted surgery. In concordance with the MIS principles, the new implants, such as the locking compression plate, and the less invasive stabilization system were well designed and put into clinical practice so as to provide effective therapeutic results in treating osteoporotic fractures and complicated articular and/or metaphyseal fractures. In treatment of the delayed union or non-union of fractures, more effective techniques were employed, including the application of bone substitutes, which are degradable and have properties of bone conduction and induction. In the repair of segmental defects of the long tubular bone, the bone transport and the vascularized bone grafts could work well. The investigation of the bone engineering revealed its great potentiality. CONCLUSION: Fracture of the extremities is a common problem and its management should emphasize the recovery of the extremity function of the patient in addition to emphasis on the replacement and fixation of the biological structures. The combination of bone engineering and microsurgery represents the development tendency in this field.

Extremities↗
PubMed2005

Hearing sensitivity and bone mineral density in older adults: the Health, Aging and Body Composition Study.

Bone mineral density (BMD) may be associated with hearing loss in older adults. Demineralization of the cochlear capsule has been associated with hearing loss in those with Paget's disease of the bone and otosclerosis. Osteoporosis may also result in cochlear capsule demineralization. We hypothesized that lower hip BMD and lower heel ultrasound measurements would be associated with hearing loss in a population-based sample of 2,089 older black and white men and women. Bone parameters and hearing function were measured at the fourth clinical follow-up visit. Audiometric threshold testing was used to measure air- and bone-conduction hearing sensitivity. BMD of the hip and its subregions was measured using dual-energy X-ray absorptiometry. Calcaneal bone measurements [broadband ultrasound attenuation (BUA), speed of sound (SOS) and the quantitative ultrasound index (QUI)] were obtained using heel ultrasound. After adjusting for known hearing loss risk factors, no association was found between hearing and any of the bone measurements in whites and black women. In black men, however, lower hip BMD was associated with higher odds of hearing loss; for each standard deviation decrease in total hip BMD, the odds of hearing loss were 1.41 (95% confidence interval 1.08, 1.83), 1.39 (95% CI 1.07, 1.82) for femoral neck BMD and 1.65 (95% CI 1.26, 2.16) for trochanter BMD. Conductive hearing loss was associated with lower heel ultrasound measurements, though only among white men. The results of this study are mixed and inconclusive. Lower BMD of the hip and its subregions was associated with hearing loss among black men, but not among whites or black women. Lower measurements on heel ultrasound were associated with conductive hearing loss, though only among white men. These results suggest that axial and appendicular bone parameters may be modestly associated with hearing loss in older men, but not in women.

Absorptiometry, Photon↗
PubMed1993

[Surgical treatment possibilities of middle ear hearing loss].

Otological surgery is performed under the operating microscope with special microinstruments. The introduction of new technical means such as the argon laser, equipped with a fiberoptic handpiece, and the sceeter microdrill have improved the results according to the statistic of Berne. An important aspect is the approach to the structures in the temporal bone. The classical retroauricular and endaural incisions are replaced whenever possible by the less traumatic transmeatal approach directly through the external ear canal without external skin lesion. Ear drum perforations and cholesteatomas with and without ossicular lesions are repaired by different types of tympano-ossiculoplasty. Destroyed ossicles are replaced by allogenic prostheses or homologous ossicles. Otosclerosis is treated by a 'small-fenestra' stapedotomy with insertion of a teflon-platinum wire piston. Bone conduction hearing aids with conventional mastoid vibrators can be replaced by more efficient bone-anchored hearing aids directly fixed in the skull. The teamwork between ear surgeon, audiologist and electronical engineer has turned out to be important for the implantation of hearing aids.

Cholesteatoma↗
PubMed1975

The association of cleidocranial dysostosis with hearing loss.

Three new cases of cleidocranial dysostosis with hearing loss are reported in this paper. The significant points concerning this association are: (1) the hearing deficit is predominantly a middle ear conduction problem secondary to structural abnormalities of the ossicles; (2) there is sometimes a small bone conduction deficit indicating either a cochlear or an eighth nerve problem; (3) the middle ear hearing loss was corrected surgically in one reported case; (4) there is dense sclerosis of the temporal bone which makes a middle ear operation technically difficult; and (5) hearing loss with cleidocranial dysostosis may be more common than the number of cases in the literature suggests.

Adult↗
PubMed2004

Safe and reliable sound threshold measures with direct vibration of the ossicular chain.

OBJECTIVES: The aim of the study was to evaluate the safety and feasibility of piezoelectric malleus vibration audiometer (MVA), which presents micromechanical vibrations to the umbo membranae tympani. STUDY DESIGN: Phase I study performed in a tertiary referral center (University Hospital). METHODS: The coupling rod of the MVA was moved slowly through the outer ear canal toward the eardrum with a micromanipulator. Coupling was completed when the rod tip touched the umbo membranae tympani. Basic audiologic measures of sound threshold obtained with direct stimulation of the malleus are presented. We used MANOVA (multivariate repeated measures ANOVA) to investigate the repeatability of MVA thresholds from one day to the other and when decoupling and retracting the coupling rod 2 mm off the umbo. We also selected the MANOVA to test for unwanted bone-conduction threshold shifts after MVA application. We assessed normality of the data by quantile-quantile plots of the residuals. RESULTS: Twenty-eight male and 10 female subjects with normal hearing, 22.2 to 34.6 years old (median age, 27.2 yr) underwent an examination. Thirty-six subjects underwent MVA, because 2 of the 38 subjects who volunteered for the study have not undergone the procedure due to the external auditory canal anatomy preventing application of the MVA. The results show that it is possible to safely and reliably measure thresholds of direct vibration of the ossicular chain. Using pure tone audiograms, no pure tone bone- and/or air-conduction threshold shifts occurred after the procedure. None of the subjects reported any other ear-related symptoms such as vertigo, tinnitus, or dizziness. Geometric mean vibratory displacements at threshold ranged from 0.55 nm at 250 Hz to 0.03 nm at 6 kHz. MANOVA demonstrated a repeatability of MVA thresholds. CONCLUSION: Malleus vibration audiometry will not allow exact linkage of actual implantable hearing aid. But the present study demonstrates that MVA can provide an audiometric tool for assessing ossicular function and integrity prior to implantation of an electronic hearing amplifier.

Adult↗
PubMed2005

Development of a large titanium bone chamber to study in vivo bone ingrowth.

In the bone conduction chamber (BCC) various materials and factors have been tested for their effect on bone graft incorporation and bone healing. However, biomaterials often have to be crushed to fit in this small chamber. Since cellular responses to biomaterials are influenced by the size and shape of particles, research concerning the evaluation of biomaterials is limited by the dimensions of this bone chamber. We enlarged and modified the BCC in order to be able to investigate the in vivo influences of biomaterials, growth factors and bone graft processing on tissue and bone ingrowth. Seven goats received four bone chambers each, three modified models and a BCC. The first model (BCC+) had two ingrowth openings, similar to that of the BCC. The second model had two round ingrowth openings (ROU). The third model had a open bottom for bone ingrowth (BOT). After 12 weeks, bone ingrowth distances were measured on histological sections and using muCT. Bone ingrowth was significantly higher (p=0.009 and 0.008) in the ROU compared to the BCC+ and the BOT, respectively. Similar results were found using muCT. The ROU model performed most similar to the BCC (gold standard) and is considered to be a promising new tool in biomaterials research.

Animals↗
PubMed1995

Congenital aural cholesteatoma: results of surgery in 60 cases.

From 1978 to 1993, 59 patients (60 ears) with congenital middle ear cholesteatoma were treated at the House Ear Clinic. The median patient age at presentation was 5 years, and the period of postoperative follow-up was 4.8 years. An intact canal wall was maintained in 58 of 60 cases and a closed middle ear space in all cases. In 12 operations, lateral graft tympanoplasty eradicated the cholesteatoma in one stage; 32 patients required a second-stage surgery to rule out recurrence, and the remaining 16 cases required three or more operations to eradicate disease and reconstruct the hearing mechanism. Thirty-five (63%) of 56 patients had a postoperative air-conduction threshold pure-tone average (PTA) within 10 dB of the best bone-conduction PTA; 91% were within 20 dB. Average speech reception threshold improved from 32 dB hearing level (HL) preoperatively to 20 dB HL postoperatively.

Child↗
PubMed2005

[Effects on hearing due to the occupational noise exposure of marble industry workers in the Federal District, Brazil].

OBJECTIVE: To evaluate the prevalence of hearing loss, its degree and type, among workers in the marble industry in the Brazilian Federal District (FD). METHOD: Workers from eight marble industries in the FD were evaluated by means of a cross sectional epidemiological study. An audiometry screening test (air conduction) was performed. Workers with hearing loss were submitted to liminal tonal audiometry air & bone conduction and speech audiometry tests using an audiometer AD-28 (Interacoustics). All subjects studied were submitted to a visual inspection of the external acoustic meatus. RESULTS: One hundred and fifty two workers were examined; mean age was 32 years (SD = 8.6); average occupational noise exposure was of 8.3 years (SD = 6.8). Audiometries demonstrated that 48.0% (n = 73) had some type of hearing loss. Among the workers with hearing loss, 50.0% had results compatible with noise-induced hearing loss (NIHL); 41.0% with incipient noise induced hearing loss, 5.0% with sensorineural hearing loss (all except NIHL) and 4.0% with conductive and mixed hearing losses. Among workers with NIHL, 57.1% had bilateral involvement, 17.1% in the right ear and 25.7% in the left ear. Among those with incipient NIHL, 13.9% were bilateral, 19.4% were only in the right ear and 66.7% were only in the left ear. CONCLUSION: Abnormal audiograms were found in 48.0% of the sample. Among those with hearing loss, the predominant cause was NIHL, followed by those classified as having incipient noise induced hearing loss. Hearing loss usually started at 6 kHz, frequently in the left ear.

Adult↗
PubMed1989

The auditory brainstem response in pediatrics.

When properly recorded and interpreted, the auditory brainstem response (ABR) serves as a powerful, noninvasive tool for the diagnosis of pediatric auditory disorders. The detection of eighth cranial nerve and brainstem dysfunction relies primarily on the comparison of wave latencies to normative data and between ears of the same patient. The description of peripheral hearing sensitivity thresholds by ABR relies primarily on the determination of the weakest stimulus intensity at which the ABR can be elicited. Differential diagnosis of sensorineural versus conductive loss is assisted by analysis of latency-intensity relationships and by bone-conducted ABR findings, whereas description of the frequency contour of the audiogram is possible using band-limited tone burst stimuli as well as other methods. From the caveats and case examples reported here, it should be clear that the ABR cannot be measured or interpreted from a patient in a "black box" fashion. Suprathreshold ABR recordings for neurotologic analysis are influenced by cochlear dysfunction, which can affect both absolute and interpeak wave latencies, and by conductive hearing loss, which affects absolute wave latencies, in such a way that the patient's audiogram must be known for proper test administration and interpretation. Interpretation of suprathreshold ABR data to infer hearing threshold sensitivity has extremely limited utility and can "clear" a child who indeed has substantial hearing loss. Threshold ABR recordings represent the most accurate means available to estimate the audiogram in the very young infant or difficult-to-test child, yet can be influenced by retrocochlear dysfunction, and require concurrent knowledge of outer and middle ear status as well as careful interpretive statements of the actual frequency range for which the audiogram has been estimated. The diagnosis of hearing impairment by ABR in a child is accomplished best when it is performed in the context of concurrent audiologic and otologic workups, with availability (on site or by referral) of a team of hearing health care professionals to evaluate and support the whole child and family. In the case of a newly diagnosed significant hearing impairment in an infant or toddler, input is needed from various professionals including those involved in education of the hearing-impaired, speech-language pathology, developmental psychology, social service, genetics, and ophthalmology, as well as the primary care pediatrician.(ABSTRACT TRUNCATED AT 400 WORDS)

Audiometry, Evoked Response↗
PubMed1989

The Bing test in the detection of conductive hearing impairment.

The Bing test is based on the principle that occlusion of the external auditory meatus improves the perception of bone-conducted sounds unless there is a conductive hearing impairment. However, its sensitivity and specificity have not been reported. Tuning-fork and audiometric Bing tests were carried out on 126 patients with otological symptoms prior to any otological history or examination. Test results were compared with the pure tone air-bone gaps. The specificity and sensitivity of each test method was estimated. The tuning-fork Bing test was less sensitive than the audiometric Bing test, but had greater specificity. However, the Rinne test with the 256 Hz fork and the loudness comparison method was more sensitive than the Bing tuning-fork test, and had similar specificity. The Rinne is therefore the better test for clinical use.

Adult↗