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PubMed2006

Output vibration measurements of bone-anchored hearing AIDS.

HYPOTHESIS: Different bone-anchored hearing aids (BAHAs) processors have different output vibration characteristics, which depend on the mechanical load and the volume setting. Responses will differ between live heads and dry or plastic skulls. BACKGROUND: The BAHA is an implantable bone-conduction device. Three different BAHA models are available. Their output vibrations have not been reported using a noncontact method with differing impedance loads, including the BAHA-fitted patient head. METHODS: Using a laser-Doppler vibrometer, vibration responses with sound input of 70- to 80-dB sound pressure level were measured on unloaded BAHAs, a dry skull, a plastic skull, and on the abutments of three live BAHA-fitted patients. Responses at different volume settings and distances from the vibrator were also tested. Frequency responses were calculated for displacement, velocity, and acceleration. RESULTS: Unloaded BAHA accelerations were approximately 30 to 50 dB higher than live-head accelerations. Live-head accelerations were similar to dry skulls in frequencies of more than 500 Hz, but much higher than the plastic skull responses. Live-head responses were more damped. The Cordelle II outperformed the other two processors by approximately 20 dB. The Classic 300 had better low-frequency responses than the Compact. The volume settings had little effect on vibration output overall. Acceleration peak was at approximately 2.5 kHz for all conditions. CONCLUSION: The BAHA processors differ in the output acceleration they can achieve with differing loads. The volume control setting has little impact on accelerations produced for most processors. The live-head responses are similar to the dry skull in frequencies of more than 500 Hz.

Acoustic Stimulation↗
PubMed1989

[Gellé test in patients of Menière's disease and fluctuating low tone hearing loss].

The threshold shift at 500 Hz bone conduction under positive and negative static pressure of 400 mmH2O applied to the external auditory canal was examined in 20 patients of Meniere's disease with fluctuating low tone hearing loss, 21 patients of sensorineural hearing loss without fluctuating and 24 normal controls. In contrast to the 10 to 15 dB threshold shift in the latter two groups (non-fluctuating group, 14.8 +/- 5.1 dB at positive and 11.1 +/- 5.7 dB at negative; normal controls, 13.6 +/- 5.4 dB at positive and 9.3 +/- 5.3 dB at negative), the former showed a significantly smaller shift (3.2 +/- 6.1 dB at positive and 2.3 +/- 4.5 dB at negative) while hearing was depressed. However, when the hearing was improved, the pressure effect became greater even in the former group (11.3 +/- 5.3 dB at positive and 9.1 +/- 4.8 dB at negative). To understand further details of these phenomena, we performed electrophysiological animal experiments. Through a small hole made on the guinea pig's cochlear bony wall, 300 mmH2O pressure was applied to the scala tympani and the threshold of 500 Hz CM was examined in both endolymphatic sac obliterated ears and non-obliterated ears. In 14 non-obliterated ears 21.1 +/- 5.1 dB threshold shift was recorded, whereas it was only 1.6 +/- 2.6 dB in 9 obliterated ears at 4-6th postoperative days. These results seem to reflect that the endolymphatic pressure is great during the early stage of hydrops.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2000

Moderate alcohol consumption and hearing loss: a protective effect.

OBJECTIVE: To determine if moderate alcohol consumption is associated inversely with hearing loss in a large population based study of older adults. DESIGN: Cross-sectional population based cohort study. Data are from the 1993-1995 examinations for the population based Epidemiology of Hearing Loss Study (EHLS) (n = 3571) and the Beaver Dam Eye Study (BDES) (n = 3722). SETTING: Midwestern community of Beaver Dam, Wisconsin. PARTICIPANTS: Residents of Beaver Dam aged 43 to 84 in 1987-1988 were eligible for the BDES (examinations in 1988-1990 and 1993-1995). During 1993-1995, this same cohort was eligible to participate in the baseline examination for the EHLS. MEASUREMENTS: Hearing thresholds were measured by pure tone air and bone conduction audiometry (250-8000 Hz.). History of alcohol consumption in the past year, heavy drinking (ever), medical history, occupation, noise exposure, and other lifestyle factors were ascertained by a questionnaire that was administered as an interview. RESULTS: In multiple logistic regression analyses controlling for potential confounders, moderate alcohol consumption (>140 grams/week) was inversely associated with hearing loss (PTA(.5,1,2,4 > 25 dB HL); odds ratio [OR] = .71, 95% confidence interval [CI] = .52, .97; where PTA is pure tone average). A similar association was found for moderate hearing loss (PTA(.5,1,2,4 > 40 dB HL); OR = 0.49, 95% CI = 0.32, 0.74). Alcohol consumption was associated inversely with the odds of having a low frequency hearing loss (OR = 0.61) or a high frequency hearing loss (OR = 0.60). These findings did not vary significantly by age or gender. There was an increase in the odds of having a high frequency hearing loss (OR = 1.35, 95% CI = 1.04, 1.75), in those with a history of heavy drinking (> or =4 drinks/day). Including cardiovascular disease or its related factors did not significantly attenuate the protective effect. CONCLUSIONS: There is evidence of a modest protective association of alcohol consumption and hearing loss in these cross-sectional data. This finding is in agreement with a small body of evidence suggesting that hearing loss is not an inevitable component of the aging process.

Aged↗
PubMed2006

Middle ear dynamics in response to seismic stimuli in the Cape golden mole (Chrysochloris asiatica).

The hypertrophied malleus in the middle ear of some golden moles has been assumed to be an adaptation for sensing substrate vibrations by inertial bone conduction, but this has never been conclusively demonstrated. The Cape golden mole (Chrysochloris asiatica) exhibits this anatomical specialization, and the dynamic properties of its middle ear response to vibrations were the subjects of this study. Detailed three-dimensional middle ear anatomy was obtained by x-ray microcomputed tomography (muCT) at a resolution of 12 microm. The ossicular chain exhibits large malleus mass, selective reduction of stiffness and displacement of the center of mass from the suspension points, all favoring low-frequency tuning of the middle ear response. Orientation of the stapes relative to the ossicular chain and the structure of the stapes footplate enable transmission of substrate vibrations arriving from multiple directions to the inner ear. With the long axes of the mallei aligned parallel to the surface, the animal's head was stimulated by a vibration exciter in the vertical and lateral directions over a frequency range from 10 to 600 Hz. The ossicular chain was shown to respond to both vertical and lateral vibrations. Resonant frequencies were found between 71 and 200 Hz and did not differ significantly between the two stimulation directions. Below resonance, the ossicular chain moves in phase with the skull. Near resonance and above, the malleus moves at a significantly larger mean amplitude (5.8+/-2.8 dB) in response to lateral vs vertical stimuli and is 180 degrees out of phase with the skull in both cases. A concise summary of the propagation characteristics of both seismic body (P-waves) and surface (R-waves) is provided. Potential mechanisms by which the animal might exploit the differential response of the ossicular chain to vertical and lateral excitation are discussed in relation to the properties of surface seismic waves.

Animals↗
PubMed2002

Carhart's notch: a finding in otitis media with effusion.

INTRODUCTION: Carhart's notch (CN) is a false depression of bone conduction (BC) thresholds at 2-4 kHz initially described in cases of stapes fixation. This study was designed to estimate the incidence and assess the clinical significance of CN in cases of otitis media with effusion (OME) in children. PATIENTS AND METHODS: Clinical records of 50 patients of OME that showed CN were analysed, retrospectively. First 24 were identified as seen in outpatients and 26 were found out of 100 consecutive cases of OME. The criteria of CN were a minimum 10 dB depression in BC at any frequency 500-4000 Hz. RESULTS: Fifty patients showed CN, with mean age of 8.8 years. All had myringotomies with or without insertion of grommets. The CN ranged from 10 to 20 dB in the majority and up to 30 dB in few cases. In 85 ears studied, the affected frequencies comprised of 2000 Hz in 80 (94%), 4000 Hz in 4 and 1000 Hz in one ear. Pre-operative tympanograms were of type B in 68 (80%), type C in 16 (18.8%) and type A in one ear. Middle ear fluid was thick glue in 57 (67%), serous in 5 (5.8%), and no fluid found in 23 (27%) cases. Oedematous, granular or polypoidal appearances of middle ear mucosa were noted in 57 (67%) of the ears. A normal mucosa was seen in 17 (20%), and no details were available in 11 (13%) ears. Post-operative audiograms showed improvements of BC thresholds in 72 (84.7%) of the ears. CONCLUSION: Our results show 26% incidence of CN in paediatric cases of OME, with evidence of thick fluid and abnormal middle ear mucosa in about two-thirds of cases. This suggests that CN may be of prognostic value for myringotomy outcomes. Statistically there is a significant correlation between presence of fluid on myringotomy and CN, and type of tympanogram and post-operative BC threshold improvement. There is no predictive value of CN in terms of character of the middle ear fluid. Studies with larger numbers may be required to determine this with more certainty. It can help clinically, however, in pre-operative assessment of these cases. It is our opinion that BC should be an essential part of routine audiometry in all cases of OME.

Audiometry, Pure-Tone↗
PubMed2001

[Auditory aspects of congenital malformations of the external and middle ears].

Auricular malformations are frequently associated to malformations of the external, the middle, and the inner ear in variable degrees. Asystematic audiometry must be performed in case of unilateral facial microsomia. This test which can be performed in very young patients can detect bilateral ear malformations necessitating auditory rehabilitation by surgery or external hearing aids. In major ear aplasia, air conduction hearing aids can rarely be proposed. In this case, bone conduction hearing aids using a mastoid transducer of through a bone anchored device yield the best auditory results with an excellent local tolerance.

Ear, External↗
PubMed2004

Comparison of canine mandibular bone regeneration by distraction osteogenesis versus acute resection and rigid external fixation.

The present study was performed (1) to explore the mechanism of skeletal healing following distraction osteogenesis of the mandible and to evaluate whether the same process is involved following acute mandibular resection and rigid external fixation, and (2) to examine the role of the periosteum in skeletal healing in both models. The study was performed using 16 mongrel dogs divided into two equal groups. In the first group, distraction of 20 mm was performed at a rate of 1 mm/day. In the second group, bone resection of 20 mm was performed, followed by rigid external fixation. The buccal periosteum was stripped in four dogs from each group, and the periosteum was left intact in the remaining four dogs. Dogs were euthanized after a survival period of either 2 or 3 months, and the new bone regenerate was evaluated. Analysis consisted of three-dimensional computed tomography scanning, histometric analysis, and immunostaining. Analysis of bone mineral content in the residual gap was conducted. Bone mineral content was increased in 3- versus 2-month survival for all groups (p < 0.05). The distracted groups had greater bone mineral content than their acutely resected counterparts, with the difference achieving statistical significance by 3-month survival (p < 0.05). Although periosteal preservation resulted in increased bone mineral content over time for all groups (p = 0.044), periosteal preservation had no significant effect on bone mineral content in the distracted groups. After periosteal stripping, however, bone mineral content was significantly increased in dogs that underwent distraction rather than acute resection and rigid external fixation (p = 0.022). Regarding histometric analysis, analysis of fibrous tissue content in the bone regenerate demonstrated that by 3 months the distracted groups had significantly less fibrous tissue in the new bone regenerate than did the acutely resected groups (p < 0.001). Regarding immunostaining, diffuse localization of transforming growth factor-beta1 was observed in all groups at 2 months, returning to nearly baseline levels by 3 months. These data demonstrate that significant bone formation in a segmental gap can be achieved after acute mandibular resection and rigid external fixation if the periosteum is preserved. However, after periosteal injury or stripping, significant bone formation can only be achieved by distraction osteogenesis. In both processes, bone formation is preceded by up-regulation of transforming growth factor-beta1.

Animals↗
PubMed1996

Bone graft proteins influence osteoconduction. A titanium chamber study in rats.

Although it is often emphasized that the matrix of bone grafts contains several growth factors, it is not known if these factors become activated and play a role in bone grafting. We therefore compared ground defatted bone which had or had not been deproteinized by heating with water to 270 degrees C at an autogenic pressure of 55 bar. This is a careful ceramic procedure which leaves the mineral unchanged. Deproteinized and non-deproteinized bone granulae derived from cortical rat bone were placed in titanium bone conduction chambers implanted bilaterally in rat tibiae. Ingrowing bone could enter the cylindrical interior of the chamber only at one end. It then penetrated the material in the chamber, but due to the length of the cylinder, it never reached the other end. The mean distance which the ingrown bone had reached in the material was then measured on histological slides. The bone formation activity was measured by TcMDP scintimetry. With the protein-containing granulae, the mean bone ingrowth distance and the scintimetric activity were increased by 41% and 31%, respectively (p < 0.01). We conclude that there is a limited favourable effect of proteins in a graft. Our grounded material had a large fracture surface area with no osteoid lining. The leakage of growth factors from such areas may explain the extraordinarily good clinical incorporation of morselized compacted allografts.

Animals↗
PubMed2005

Surface microtopography regulates osteointegration: the role of implant surface microtopography in osteointegration.

Increased surface roughness of dental implants enhances the process of osseointegration. It increases bone conduction and increases BIC in all types of bone, resulting in elevated removal torque values. Surface roughness elevated the CSR of implants implanted in adverse conditions as augmented ridges and sinuses and areas of poor bone, such as the posterior maxilla, and in some cases abolished the deleterious effect of smoking. A growing number of clinical studies suggest that early and immediate loading of rough-surfaced implants may lead to predictable osseointegration. However, it is important to note that these studies provide short-term results based on radiographic observation and clinical mobility only. Before we adopt new surgical and prosthetic guidelines, longer and broader studies are needed. Most recent research has examined the effect of surface roughness on bone healing around implants in vivo and the influence of surface roughness on osteoblasts in vitro. In a study just published, it was found that changing the surface chemistry by submerging an implant in an isotonic sodium chloride solution following acid etching to avoid contamination with molecules from the atmosphere significantly increased osteoblast differentiation in vitro and BIC in vivo. This finding may lead us to a new era in dental implants.

Animals↗
PubMed1991

Gap healing enhanced by hydroxyapatite coating in dogs.

During prosthetic implantation, gaps between the implant surface and the surrounding bone may occur resulting in reduced implant stability. In these instances bone-conductive materials might augment the formation of hosting bone into the pores of the implant and insure earlier implant stabilization and fixation by bony ingrowth. Titanium-alloy cylinders with a porous-titanium-alloy plasma spray coating were implanted into the medial femoral condyles in six mature dogs. In another group of six dogs, matched in age, weight, and gender, hydroxyapatite (HA) coated implants were used. All implants were surrounded by a 1-mm gap. Unilateral osteopenia of the knee, with a 20% reduction of bone density as judged by computed tomography scanning, was induced by 12 weekly intraarticular injections of carrageenin into the right knee before surgery. Four weeks after implantation, the HA-coated implants were compared to the parent porous-titanium implants by mechanical testing and histomorphometry. A marked positive influence of HA coating on bone mineralization and the strength of the interfacial bone between the bone and implant was found. The increment in interface shear strength and shear stiffness was three- to fivefold in osteopenic bone and two-fold in control bone. Coating of an unloaded porous-titanium-coated implant with HA accelerates the rate of bone ingrowth and thereby provides relatively high, early interfacial shear strengths in the presence of an initial gap between bone and implant even in the presence of osteopenic host bone.

Animals↗
PubMed1996

Basic fibroblast growth factor promotes bone ingrowth in porous hydroxyapatite.

The effect of basic fibroblast growth factor on tissue ingrowth and differentiation in porous hydroxyapatite of coralline origin was studied in a bone chamber model. The hydroxyapatite with or without basic fibroblast growth factor was placed in 22 mm3 titanium bone conduction chambers implanted bilaterally in rat tibiae. Ingrowing bone could enter the cylindrical interior of the chamber only at 1 end. It then penetrated the porous hydroxyapatite inside the chamber. The distance that the ingrown tissue had reached into the material then was measured on histologic slides. Because fibrous tissue always reached further into the material than did bone, both total tissue ingrowth and bone ingrowth distances were measured. In implants supplemented with 0.04 microg basic fibroblast growth factor in a hyaluronate gel carrier, the bone ingrowth distance was increased by 70% at 6 weeks, as compared with paired controls in the contralateral leg. The total tissue ingrowth distance also was increased by 58%. When the dose of basic fibroblast growth factor was increased to 1.0 microg, still using the hyaluronate carrier, there was no difference in bone ingrowth compared with controls, but this dose still increased the total tissue ingrowth. In hydroxyapatite with 1.5 microg basic fibroblast growth factor without hyaluronate gel at 4 weeks, no increase in bone ingrowth was shown, but total tissue ingrowth was increased. At 6 weeks, bone ingrowth and total tissue ingrowth were increased by 41% and 33%, respectively. With a lower dose of 0.15 microg without carrier, only the total ingrowth distance was increased. The results suggest that basic fibroblast growth factor may promote tissue ingrowth into porous hydroxyapatite and that bone ingrowth may be increased by appropriate doses. The hyaluronate gel carrier reduced the optimal dose.

Animals↗
PubMed1984

Phase relationship between bone and air conducted impulse signals in the human head.

Using the cancellation method we investigated the phase relationship as well as the amplitude ratio between impulse signals transmitted simultaneously via both bone and air conduction channels. The psychophysical findings indicated a phase difference corresponding to a time delay of about 0.9 ms by which the air input led the bone input in the case of frontal bone stimulation. Changing the polarity of the bone conduction signal a maximum in the loudness sensation was found just in the same phase difference. The psychophysical findings, predicted mathematically, were verified with brainstem evoked potentials elicited to similar signals. Preliminary results showed that the time lag observed relied on the location of the bone vibrator on the head and furthermore on the frequency used. This suggests different transmissions of vibratory energy reaching the inner ear along the skull.

Bone Conduction↗
PubMed1995

Reporting operative hearing results: does choice of outcome measure make a difference?

Choice of outcome measure in reporting hearing results following otologic surgery, including the frequencies used and use of pre- or postoperative bone thresholds, varies from author to author. In this study, data from 550 ossicular reconstruction and pediatric tympanoplasty surgery patients were used to generate a variety of outcome measures, including pure-tone thresholds for frequencies from 0.5 kHz to 8 kHz and different frequency combination pure-tone averages (PTAs) and air-bone gaps. There were no significant differences between mean pre- and postoperative bone conduction thresholds for any of the frequencies from 0.5 to 4 kHz nor for a PTA of 1, 2, and 4 kHz. Mean postoperative air-bone gap differed by no more than 2 dB across six different frequency combination PTAs. If "success" is defined as a postoperative air-bone gap of less than 20 dB, the largest difference in success rate across the six frequency combinations was 5%. There was also little difference in mean postoperative air conduction PTAs for any of the combinations that include frequencies through 4 kHz. Choice of a more conservative or more liberal definition of success was more important than whether air-bone gap or air conduction PTA was used. The authors recommend that a standard reporting procedure be adopted that ensures presentation of the results in a format such that more direct comparisons can be made within the published literature.

Adolescent↗
PubMed2005

Ossiculoplasty with intact stapes and absent malleus: the silastic banding technique.

OBJECTIVE: To report an original method of ossicular reconstruction with intact stapes and absent malleus. Ossiculoplasty is performed with a total ossicular replacement prosthesis positioned from the stapes footplate to the under-surface of the tympanic membrane, using a Silastic banding technique to stabilize the prosthesis. STUDY DESIGN: A prospective study of ossicular reconstruction using the Silastic banding technique. A consecutive series of cases with intact stapes superstructure and missing malleus handle (Austin-Kartush Group C) is presented. SETTING: One tertiary referral center. PATIENTS: Ninety-nine patients who underwent total ossicular reconstruction with Silastic banding technique were enrolled in the study from January 2000 to December 2002. INTERVENTIONS: Ossiculoplasty with total ossicular replacement prostheses with Silastic Rubber Band for chronic otitis media and non-inflammatory disease. MAIN OUTCOME MEASURES: Preoperative and postoperative audiometric evaluation using conventional audiometry. Air-bone gap, bone-conduction threshold, and air-conduction threshold were assessed. Postoperative audiometry was performed at the 6th, 9th, 12th, 18th, 24th, and 36th months. RESULTS: Overall, a postoperative air-bone gap closed to within 10 dB was achieved in 61.5% of cases. An air-bone gap smaller than 20 dB was obtained in 77% of cases. Postoperative improvement of air-conduction thresholds by at least 20 dB was found in 51% of cases. There was no case of postoperative sensorineural hearing loss. One case of extrusion of the prosthesis was seen (1%). CONCLUSION: Stabilizing the total ossicular replacement prosthesis with the Silastic banding technique when performing ossicular reconstruction is a safe, effective method when the stapes supra-structure is present and the malleus absent.

Adolescent↗
PubMed1995

Air-bone gap in patients with X-linked stapes gusher syndrome.

It is often possible to elicit the stapedius reflex in patients suffering from recessive X-linked progressive mixed deafness syndrome with stapes gusher. The presence of an air-bone gap in the audiogram and the ability to elicit the stapedius reflex are conflicting. Measurements were performed on two patients who were suffering from this syndrome, to establish whether the hearing loss was of the mixed or purely sensorineural type. It was argued that, owing to congenital malformations, the audiovestibular system might act as a more than normally efficient transducer, to convert skull vibrations into inner ear fluid motions, leading to bone conduction thresholds that are better than expected. The results of tone and speech audiometry, stapedius reflex measurements, and brainstem evoked response audiometry in this study showed a pattern similar to that generally seen in patients with purely sensorineural hearing loss. This supports the hypothesis that the air-bone gap in the audiogram does not have the usual significance of a conductive hearing loss component.

Adult↗
PubMed2006

Audiometric patterns in ototoxicity of intra-arterial Cisplatin chemoradiation in patients with locally advanced head and neck cancer.

This study describes audiometric patterns of ototoxicity in a consecutive series of patients uniformly treated with intra-arterial high-dose cisplatin chemoirradiation for advanced cancer of the head and neck. Air conduction thresholds were measured from 0.125 to 16 kHz and bone conduction thresholds were measured from 0.5 to 4 kHz. The overall audiometric pattern was characterized by maximum threshold shifts after the 2nd cisplatin infusion and a maximum total threshold shift at 8 kHz, irrespective of gender, age, pretreatment sensorineural hearing loss (SNHL) or subjective complaints during therapy. A hearing deterioration gradient was observed from (ultra-) high to low frequencies, worse with increasing pre-existent SNHL and with increasing cumulative dose of cisplatin chemoradiation. Cisplatin chemoradiation-induced hearing loss seemed to reach a plateau at higher levels (75-80 dB HL) for frequencies above 8 kHz compared to frequencies up to 8 kHz (45-60 dB HL). Recovery of SNHL was found after therapy in 27 ears characterized by extensive hearing loss at frequencies 1, 2 and 4 kHz.

Antineoplastic Agents↗
PubMed2003

[Perilymphatic effusion as a complication of otosclerosis].

INTRODUCTION: Stapes gusher means the leakage of perilymphatic liquid when opening the perilymphatic cistern. The perilymphatic liquid with a high pressure gushes with a great flow out of the cistern when the stapedotomy is executed. Otosclerosis surgery sometime brings to light abnormal contact between the inner ear and the sub-arachnoidian spaces in patients who didn't presented ear malformations. It's a very rare event (1/1000) which is different from a much more common and more moderate form of perilymphatic liquids high pressure (1/200). About 4 clinical observations, we compared our experience with other authors in specialist reviews. PURPOSE OF THE STUDY: About four observations, we confronted our experience with that of the literature. MATERIAL AND METHODS: Retrospective study between 1971 and 1998. It was about 3 males and 1 female, without antecedent except one of them who had been operated 5 years before for the opposite ear without gusher but without good audiometric result. They presented a conductive deafness with no answer of the stapedial reflex. We had 4 geysers during the platinotomia which were sealed with some connective tissue. RESULTS: Two patients had a post operative complete sensory hearing loss, one, a sensitive decline of the conduction thresholds (average 50 dB), the last one kept his bone conduction level with a mild sensory hearing loss. The most recent case had a scanner preoperatively which had not shown abnormality except for the focus of otosclerosis. DISCUSSION: Perilymphatic gusher is an unpredictable event that can not be diagnosed before the surgery, nether with clinical facts nor radiological elements. This involves serious consequences concerning not only the continuation of the surgical operation and the prognostic of the hearing but also concerning the danger of secondary meningeal infections. The best way to proceed in case of favourable cases consists in fitting the ossicular prothesis into the stapedotomy, when it's not to wide. Pieces of muscle can be used in some cases, taped on with biologic glu. Various techniques are used to lower the pression of the cerebrospinal liquid: hypertonic solutes, diuretic drugs, lumbar diversion. In all cases, it is necessary to start a wide spectrum antibiotic treatment and a vaccination against pneumococcis. CONCLUSION: The surgeon has to know all the option of the treatment when confronted with this situation in order to try to avoid tricky defect of the inner ear.

Adult↗
PubMed1988

[Clinical trial of BOBCAT: 1st report on the reliability and validity of computerized pure-tone audiometry].

Computerized diagnostic audiometry is quickly emerging as a viable productivity tool in the audiology clinic. To date, there has been little reported on its reliability and validity with the hearing-impaired. The 'Battery of Basic Computerized Audiometric Tests' (BOBCAT) is a computer program which puts a wide variety of clinical hearing tests under computer control. The purpose of the present study was to ascertain the reliability and validity of BOBCAT in the measurement of hearing sensitivity. A field study was conducted in a group of 92 workers exposed to noise to measure air- and bone-conduction thresholds. Coefficients of reliability of 0.85 and higher were obtained between air and bone thresholds for both methods of testing; that is, manual and computer-controlled audiometry. The same measurement between manual and computerized air-conduction pure-tone thresholds gave values ranging from 0.93 to 0.98. A principal-components analysis documented content validity of computerized audiometry. These results are interpreted as clear evidence of both reliability and validity of the BOBCAT procedure, with one exception: 6.7% of all observations are showing air-conduction computerized thresholds of -10 dB at one or more frequencies, with no confirmation by manual audiometry. This is attributed to insufficient randomization of intervals between stimuli, a problem which should be taken care of by new versions of the software.

Adult↗