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PubMed1997

The bone-anchored hearing aid: reference quantities and functional gain.

One of the most important parameters of a hearing aid is its gain characteristics. Under ideal circumstances, the gain and the functional gain (FG) are the same for an air conduction device. This is not the case, however, with bone conduction devices, e.g., the bone-anchored hearing aid (BAHA). In this article, the relation between the gain and the FG is derived for bone conduction devices including the BAHA. Reference quantities used when measuring bone conduction devices also are presented.

Auditory Threshold↗
PubMed2005

Pure tone audiometry in children.

OBJECTIVE: Our purpose was to evaluate performance of the children on pure tone audiometry (PTA), and role of age, concentration level (CL) and otitis media with effusion (OME) in testing process. METHODS: This study was prospectively performed on 100 consecutive children referred for PTA between 24 and 120 months of age. After the audiologists' decision on test technique, the followings were noted: CL (by using a visual analog scale), test duration, test convenience (TC) and the problems (interruption, delay, crying) during the test. By using pure tone averages (PTAv), mean hearing level (MHL) and mean gap (MG) were calculated. RESULTS: PTA was achieved in 90% of the children and PTAv of bone and air conduction in the both ears were obtained in 86% (play audiometry with earphones (PAE): 73%, conventional audiometry (CA): 22%). These ratios were not different between the children with and without OME. About 55% of the younger children than 36 months were failed in PTA, while this ratio was 4.5% in the children between 36 and 120 months. Only difference between PAE and CA tests was in MHL. In OME group, only TC was found to be lower. Correlation analysis showed that CL was correlated with age. Test duration was correlated with MG and MHL, but found to be dependent on only MG. Further, it was found that test choice of the audiologist was correlated with age and CL, but dependent on only CL. CONCLUSIONS: PTA is available in children depending on their age and particularly CL; hence, performance in PTA is directly related with audiologists' assessment the children and cooperation before starting the test. Meanwhile, test duration appears to be directly associated with the work on detection of the gap between air and bone conduction thresholds.

Age Factors↗
PubMed2004

Estimating air-bone gaps using auditory steady-state responses.

Auditory steady-state responses (ASSR) were recorded using stimuli presented both via air conduction (AC ASSR) and bone conduction (BC ASSR) in 10 normal-hearing subjects with different degrees of simulated conductive hearing losses. The ASSR-estimated ABG (air-bone gap) was compared with the ABG measured using traditional pure-tone audiometric procedures. Reproducibility of the BC ASSR electrophysiological thresholds was also assessed. Additionally, a group of five subjects with profound sensorineural hearing loss was used to establish stimulation levels in which the BC ASSR was contaminated by stimulus artifact. Results of this investigation showed that the ASSR and behavioral ABGs were strongly correlated with each other (r = .81). However, ASSR-estimated ABGs slightly overestimated the magnitude of the behavioral. Reproducibility of the BC ASSR electrophysiological thresholds was good. Data from the five subjects with profound hearing loss, however, demonstrated that the levels where stimulus artifact became problematic were relatively low. This means BC stimulation may be appropriate only for subjects with normal or mildly impaired cochlear sensitivity.

Adult↗
PubMed2003

[Transvestibular closure with an autologous bone graft as surgical repair of a nasoseptal defect due to Le Fort-I osteotomy].

Defects of the nasal septum are a common complication after nasal surgery. Affected patients frequently suffer from bleeding, crusting and impaired nasal air flow. The surgical closure of septal defects remains a distinctive challenge. Though many different techniques have been described, the failure rate of this procedure remains high. In the case presented here, a large basal septum defect occurred after a prosthetic Le Fort-I osteotomy. The attempt to cover the distance between the bony nasal floor and the nasal septum with pedicled mucosal flaps failed due to extensive scar formation of the nasal mucosa. Therefore a nasal floor elevation by insertion of an autologous bone graft from the iliac crest was conducted. The bone graft was connected with the hard palate via two titanium screws. Other than with an autologous cartilage graft, no major resorption of the bone graft is to be expected. This indirect method for the closure of a basal nasal septum defect is new.

Alveolar Ridge Augmentation↗
PubMed1979

Hearing sensitivity of adults with cleft lip and/or palate.

This study is designed to investigate the hearing sensitivity of adults with repaired clefts of the lip and/or palate or congenital velopharyngeal inadequacy (VPI). Hearing sensitivity was analyzed with respect to pure tone air conduction thresholds and the extent of air bone gap. In addition to age, type of cleft and type of physical management of the palate were taken into account. The results of the study indicated that the thresholds of individuals with clefts of the palate or VPI exceeded normal limits. There were no significant differences in thresholds among the four types of palatal clefts or among the types of physical management of the palates.

Adolescent↗
PubMed2001

[Stapedectomy in the treatment of otosclerosis in children].

In the years 1994-2000 in the Laryngology Department Silesian Medical Academy in Zabrze 167 stapedectomy were performed in 143 patients with otosclerosis. In this group of patients 11 stapedectomies in 8 children aged from 9 to 17 years were performed. 5.6% of all the patients with otosclerosis treated in our Department were children. The purpose of this study was to analyze the audiologic results of stapedectomies in children. The postoperative evaluations were performed in the period from 6 months to 6 years after the surgical treatment. In the estimation of the hearing state we analyzed the change of the air-bone gap, an average air conduction hearing improvement, the rate of percentage hearing improvement and an average hearing loss by Bell Telephone Laboratories. In all the operated children we observed the decrease of the air conduction hearing level. Stapedectomy was successful (postoperative air bone gap within 10 dB of the preoperative bone conduction) in 63.6% of the patients. In 3 cases the air bone gap was lower than 20 dB (27.3%). In one case it was greater then 20 dB. The air bone gap closure was at the average of 5.75 dB level. The results were comparable with the other authors. Stapedectomy can be an effective procedure for correcting conducting hearing losses due to the otosclerosis in the pediatric patients.

Adolescent↗
PubMed2006

A new implantable middle ear hearing device for mixed hearing loss: A feasibility study in human temporal bones.

HYPOTHESIS: To assess the feasibility of a new, active middle ear device in temporal bones (TB). BACKGROUND: This device is designed for patients with mixed hearing loss subsequent to chronic middle ear infection, surgery, or trauma. This Bell-Vibroplasty is built from a VIBRANT MED-EL Vibrant Soundbridge and a Kurz Bell titanium partial ossicular replacement prosthesis. METHODS: In three fresh TBs, healthy and reconstructed middle ears were analyzed by means of laser Doppler interferometry. The sound transmission properties of a partial ossicular replacement prosthesis and a passive and an active Bell-Vibroplasty were compared with healthy middle ear function. RESULTS: The measurements provided reliable results with small standard deviations and good signal-to-noise ratios. The performance levels of the partial ossicular replacement prosthesis and of the passive Bell-Vibroplasty were comparable with that of healthy middle ear function. The activated Bell-Vibroplasty provided linear function and a flat frequency response within the measured frequency range (500 Hz-8 kHz), with peak deviations of less than 10 dB. The maximum output of the Bell-Vibroplasty was equivalent to 125-dB sound pressure level. CONCLUSION: Bell-Vibroplasty is feasible in TBs. Bell-Vibroplasty performance in TBs is sufficient to allow for a clinical trial as a next step.

Acoustic Stimulation↗
PubMed1991

[Diagnosis of fractures by sound].

For the purpose of objective evaluation of the sound diagnosis the authors have generalized an experience of application of four methods of the acoustic diagnosis of bone fractures. There have been compared the efficiency of the auscultatory percussion method, the method of its objectivization by means of measuring devices, the sound diagnosis method, following the pattern of auscultatory percussion and self-sustained oscillation measuring method. There have been noted the high efficiency and up to 98% coincidences with clinico-roentgenologic data in case of application of the sound diagnosis method with the self-sustained oscillation systems.

Adolescent↗
PubMed1992

Cytogenetic analysis of pulmonary lavage and bone marrow cells of rats after repeated formaldehyde inhalation.

Cytogenetic analyses were conducted on bone marrow and pulmonary lavage cells from rats that received repeated inhalation exposures to formaldehyde. Male Sprague-Dawley rats were exposed to 0, 0.5, 3, or 15 ppm formaldehyde for 6 h per day, 5 days per week, for 1 and 8 weeks. There was no significant increase in chromosomal abnormalities in the bone marrow cells of formaldehyde-exposed rats relative to controls. There was a statistically significant increase in chromosomal aberrations in the pulmonary lavage cells from rats that inhaled 15 ppm. There were 7.6 and 9.2% of the scored pulmonary lavage cells that had aberrations following 1 and 8 weeks, respectively, of 15 ppm formaldehyde exposure (with control levels of 3.5 and 4.8%, respectively). The predominant damage seen was chromatid breaks. These findings indicate that marginal but statistically significant genotoxic effects could be detected locally in lung alveolar macrophages, but not distally in bone marrow, following repeated formaldehyde exposures only at a high concentration that is carcinogenic to rats. The biological significance of this effect is uncertain since formaldehyde is not considered to be a lung carcinogen in rats.

Administration, Inhalation↗
PubMed2004

[Experimental study of poly-DL-lactic acid membrane guided bone regeneration in rabbit radii bone defects].

This study was conducted to observe bone regeneration guided by poly-DL-latic acid (PDLLA) membrane in rabbit radii bone defects and to explore the mechanism of the membrane guided bone regeneration (MGBR). The animal models of bony and periosteous defects were established in both radii of 40 adult New Zealand white rabbits. The left defect as the experimental side was bridged with PDLLA membrane tube, the right side as the controlled side was untreated. The specimens were collected at 2, 4, 8 and 12 weeks postoperatively. General observation, X-ray, histological observation and biomechanical examination were applied to the repair of the models of MGBR in both groups. Two weeks after operation, with much new bony callus formed outside the tube at both fragments, the membrane tube covered with connective tissues was filled with haematoma and fibrous callus. Twelve weeks after operation, the PDLLA membrane became white and its tube shape was still maintained. However, new bone callus outside the tube almost completely disappeared, and inside the tubes all radii bone defects were successfully repaired with bony union. On the controlled sides, bone defects were filled with connective tissues 2 weeks postoperatively. And 12 weeks after operation, the typical nonunion that had been formed after bone marrow canals were sealed with cortical bone. On the experimental side, the strength of the newly formed bone at the 12th week was higher than that at the 8th week (P<0.05), whereas the biomechanical examination could not be done on the controlled side. Therefore, these findings suggested that the bone regeneration could be successfully guided by PDLLA membrane, and this MGBR technique might be generally used in the treatment of bone defects and nonunion.

Animals↗