Change In Bone Conduction Thresholds Research Articles

Influence of Changes in Bone-Conduction Thresholds on Speech Audiometry in Patients Who Underwent Surgery for Otosclerosis.

Otosclerosis is an underlying disease of the bony labyrinth that results in hearing loss. In some cases, the involvement of the bony part of the cochlea results in mixed hearing loss. The aim of this analysis was to seek a correlation between the results of speech audiometry tests and the changes in bone-conduction thresholds observed after surgical treatment. The analysis included 140 patients who were hospitalized and surgically treated for otosclerosis. The patients who were treated with stapedotomy were divided into subgroups based on the value of the bone-conduction threshold before the surgery. An audiological assessment was performed, with pure-tone threshold audiometry and speech audiometry tests taken into account. The effectiveness of the surgery was judged by the change in the speech audiometry test results after 12 months of observation. After the surgery, it was found that a significant improvement, characterized as achieving 100% understanding of speech, occurred in 61.90% of the patients. There is a correlation between the improvement in speech audiometry tests and bone-conduction curve after stapedotomy. The changes achieved in the bone-conduction curve at the frequency range up to 3,000 Hz (hertz) had a significant impact on the improvements in speech audiometry test results. Higher frequencies provide more data for improving the hearing process. A mean bone-conduction threshold between 21 and 40 dB (decibels) in the pure-tone audiometry examination performed before surgery is a favorable prognostic factor in the improvement of the bone-conduction threshold after surgery.

A prospective comparative study on the short-term effect of endoscopic myringoplasty in dry and wet ears

Objective:To investigate the success rate, dry ear time and hearing improvement of myringoplasty on chronic suppurative otitis media（CSOM） patients under dry and wet ear conditions. Method:Patients with CSOM who underwent endoscopic type Ⅰ tympanoplasty between January 2018 and October 2019 in West China Hospital were prospectively enrolled. Before the operation, Ear HRCT, oto-endoscope and pure tone audiometry were completed. According to whether there was mucus and purulent secretion of middle ear accompanied with edema of tympanic mucosa, patients were divided into wet ear group（32 cases） and dry ear group（69 cases）. All patients were followed up at half-month, 1 month and 3 months after surgery, with assessment of endoscopy and pure tone audiometry. SPSS 19.0 was used to compare the therapeutic effect of myringoplasty on different condition CSOM patients. Result:Compared with wet ear group, a higher level of perforation healing rate was found in dry ear group, but there was no significant difference between them（97.1% vs. 90.6%, P=0.367）. The rate of dry ear was 98.6% and 93.7% in dry ear group and wet ear group respectively within three months after surgery, among which the rate of dry ear was 14.5%, 52.2% and 31.9% in dry ear group in half month, 1 month and 3 months after surgery, while that in wet ear group was 28.1%, 40.6% and 25.0% respectively. There was no significant difference in the time to dry ear after surgery between the two groups（P=0.172）. Meanwhile, changes of air bone gap（ABG） between pre-operation and 3 months after operation in dry and wet ear groups was similar [（9.87±1.08） dB vs. （12.74±1.77） dB, P=0.154]. When included patients were analyzed as a whole, the ABG at 3 months was significantly lower than 1 month after operation（P<0.01）, similar result was also found when compared the ABG at 1 month after operation with pre-operation（P<0.01）. The air conduction threshold was improved from （42.09±1.74） dB HL before operation to （29.41±1.61） dB HL at 3 months after operation（P<0.01）, however, there was no significant change in bone conduction threshold（P=0.338）. Conclusion:There is no significant difference in the therapeutic effect of myringoplasty on CSOM patients under dry and wet ear conditions. Direct type Ⅰ tympanoplasty on wet ear patients has no adverse effect on the prognosis.

Treatment using diffuse laser energy of cochlear and vestibular fistulas caused by cholesteatoma.

To measure the outcomes of laser treatment of cholesteatoma covering cochlear and vestibular fistulas. Cholesteatoma matrix over the fistula was denatured; the power density was sufficient only to gradually heat, but not vaporise, the keratin-forming matrix. The denaturing speed was controlled so that the integrity of the fistula cover was maintained. The change in bone conduction threshold and the residual rate of cholesteatoma at the fistula were measured. Thirty-six fistulas were assessed. There were seven cochlear fistulas. All were 5 mm or less in maximum length. For the entire group, the average change in bone conduction threshold was -0.3 dB. For cochlear fistulas, the average change in bone conduction was + 0.2 dB. The distribution of hearing results for the entire group was Gaussian; the apparent changes in hearing could be attributed to errors associated with testing. All patients underwent second-stage surgery. In all cases, the cholesteatoma was completely cleared from the fistula site. There were no facial palsies. Laser denaturing of cholesteatoma matrix over fistulas measuring 5 mm or less of vestibular apparatus and the cochlea is effective at eliminating cholesteatoma, and is not associated with cochlear hearing loss or facial palsy.

Assessment of Bone Conduction Thresholds After Surgical Treatment in Patients with Labyrinthine Fistula.

This study aimed to analyze the bone conduction thresholds before and after surgery in chronic otitis media patients with cholesteatoma who had labyrinthine fistula and whose cholesteatoma matrix had been completely cleaned. The study was performed between 2013 to 2017 with 23 chronic otitis media patients who had labyrinthine fistula with cholesteatoma and who were operated at the Department of Otorhinolaryngology of Dicle University School of Medicine. Patients were assessed by anamnesis and examination and when necessary, by temporal computerized tomography and diffusion magnetic resonance imaging. Bone conduction thresholds at frequencies of 500, 1000, 2000, and 4000 Hz were determined by audiometric examination and they were compared before and after surgery. Of the 23 patients, 12 were female and 11 were male; their age range was 10-55 (26.04±14.13) years. In the post-operative period, it was possible to conduct audiological follow-up on 20 patients. In these follow-ups, 16 patients showed no change in bone conduction thresholds, two patients showed worsening, and two showed improvement. When pre- and post-operative bone conduction thresholds at each frequency were compared separately, no significant difference was found (p=0.937). No statistically significant difference was found between the pre- and post-operative means at the four frequencies (p=0.712). In this study, we found that to reduce complications relating to cholesteatoma, it might be necessary to completely remove the matrix especially in the case of type 1 and 2 labyrinthine fistulas.

Effect of drill noise on contralateral hearing after mastoidectomy in cases of unilateral Chronic Otitis Media

Introduction: The mainstay of treatment of Chronic Otitis Media (COM) is Tympanoplasty with or without Mastoidectomy. This study was conducted in patients undergoing Tympanoplasty with Mastoidectomy to assess Sensorineural Hearing Loss (if any) due to drill noise on the contralateral ear. Materials and Methods: A total of 25 patients with unilateral COM scheduled to undergo Mastoidectomy and Tympanoplasty who fulfilled inclusion criteria were recruited in the study, and a prospective, observational pilot study was carried out. Pure Tone Audiometry (PTA) and Transient Evoked Otoacoustic Emissions (TEOAE) were recorded preoperatively and postoperatively to assess hearing loss if any on the contralateral side. Results: There was no change in bone-conduction thresholds in the contralateral ear by PTA postoperatively. However, there was a significant worsening in the values of signal-to-noise ratio of TEOAE at all the frequencies in the postoperative period. The mean TEOAE recordings were, however, above 3 dB SPL. Conclusion: There are statistically significant effects of drill noise on the inner ear function on the contralateral ear as detected by TEOAE; however, the effects are not detectable on PTA. Larger studies with a longer follow-up period will be required to determine if the early postoperative effects on TEOAE are reversible or persist.

Risk of progressive hearing loss in untreated superior semicircular canal dehiscence.

Patients with incidental or minimally symptomatic superior semicircular canal dehiscence (SSCD) are usually observed, without surgical repair. However, it remains unknown whether a labyrinthine fistula of the superior semicircular canal is associated with progressive conductive or sensorineural hearing loss over time. Retrospective review at two tertiary care academic referral centers. Adults analyzed were diagnosed with SSCD by high-resolution temporal bone computed tomography and vestibular evoked myogenic potential testing and observed with a minimum of two sequential audiograms. Patients with other potential causes of hearing impairment were excluded. A total of 40 ears in 30 adult patients (median age: 59 years; 63% female) were analyzed. Median audiometric follow-up was 23 months (range 1-136 months). None experienced a sudden hearing loss over the follow-up period. In patients with audiometric follow-up of at least 20 months (median 34 months), the median change in air-conduction pure tone average and air-bone gap was 0.9 decibels (dB) per year (interquartile range [IQR] 0-2.1) and 0.7 dB per year (IQR 0-2.0), respectively. Speech discrimination scores did not differ when comparing median initial (100%) and median final (98%) scores (P = 0.77). There was no statistically significant change in bone-conduction thresholds at 0.5, 1, 2, and 4 kHz over the period of observation. The risk of progressive hearing loss with observed SSCD is low during short- and intermediate-term follow-up. Further studies are necessary to determine whether late hearing loss occurs. Such information may be critical toward patient counseling regarding the need for and timing of surgery. 4. Laryngoscope, 127:1181-1186, 2017.

A retrospective study on post-operative hearing of middle ear cholesteatoma patients with labyrinthine fistula

Conclusions: There is no significant change in bone conduction threshold after operation, so the tympanoplasty can be done to maintain hearing when conditions allow. Objective: To study the impact of surgical treatment on hearing of cholesteatoma patients with labyrinthine fistula. Methods: The clinical data of 35 patients (35 ears) with labyrinthine fistula, which were caused by cholesteatoma, were analyzed retrospectively. The hearing of 21 patients was followed up. Results: Three months to 5 years follow-up of 21 patients were accomplished by pure tone audiometry and other details. There was no recurrent cholesteatoma in the patients. Compared with pre-operative average bone conduction at 0.5, 1, 2, 4, and 8 kHz, 12 cases had a difference less than 5 dB, three patients’ hearing improved (more than 10 dB), and five cases declined (more than 10 dB). One patient received cochlear implantation 3 months after the surgery. The average bone and air conduction thresholds at 0.5, 1, 2, 4, and 8 kHz had no obvious change (p > 0.05) in 11 patients managed by a canal wall down mastoidectomy with tympanoplasty.

Pros and Cons of Round Window Vibroplasty in Open Cavities: Audiological, Surgical, and Quality of Life Outcomes.

To evaluate the audiological, surgical, quality of life, and quality of sound outcomes in adults with open cavities implanted with the Vibrant Soundbridge (VSB) implant using round window (RW) vibroplasty approach. Retrospective study. Otolaryngology department, tertiary referral hospital. Twelve adult patients with conductive or mixed hearing loss, all with previous middle ear surgery, underwent RW vibroplasty in an open cavity. Compound action potential thresholds were assessed during surgery. Surgical complications were recorded. Subjective benefit was evaluated using the Nijmegen Cochlear Implant Questionnaire (NCIQ), Glasgow Benefit Inventory (GBI), and Hearing Implant Sound Quality Index (HISQUI29) tests. Mean follow-up was 42 months (range 12-76). There was no significant change in bone conduction thresholds after surgery. Mean functional gain was 34.3 dB and speech discrimination score at 65 dB significantly improved from 14 to 83%. Extrusion of the wire link was the main surgical complication in four patients. All NCIQ domains improved after surgery. All patients had a positive overall GBI score (mean 35.0). Mean HISQUI29 score was 152.8, on average the quality of sound being defined as "very good." VSB is an effective method of hearing restoration for adults with open cavities suffering from conductive or mixed hearing loss. Intraoperative electrocochleography may be considered of significant help to check the coupling to the inner ear. The high rate of extrusion suggests that middle ear obliteration may be considered in these patients.

Primary stapedotomy in children with otosclerosis: A prospective study of 41 consecutive cases.

To prospectively evaluate hearing outcomes in children with otosclerosis undergoing primary stapes surgery. A nonrandomized, nonblinded, prospective case series. Thirty-four consecutive pediatric patients who underwent 41 primary stapedotomies for otosclerosis in a tertiary referral center were included. Patients were included when there was evidence of otosclerotic stapes fixation and they had available postoperative pure-tone audiometry. Patients underwent primary stapedotomy with vein graft interposition and reconstruction with a regular piston, bucket handle prosthesis, or total ossicular replacement prosthesis. Hearing results were evaluated using pre- and postoperative four-frequency (0.5, 1, 2, and 4 kHz) audiometry. Air-conduction thresholds, bone-conduction thresholds, and air-bone gaps were measured. Postoperative audiometry was performed at 3, 6, 9, 12, 18, and 24 months after surgery and at a yearly interval thereafter. Overall, a postoperative air-bone gap closure of 10 dB or less was achieved in 93% of cases and to within 20 dB in 98% of cases. Mean gain in air-conduction threshold was 23 dB for the entire case series, and mean air-bone gap closure was 23 dB. Postoperative sensorineural hearing loss, defined as changes in bone-conduction thresholds exceeding 10 dB, occurred in one case at last follow-up. The bone-conduction threshold deteriorated 13 dB in this case. Primary stapedotomy is a safe and feasible treatment option in children with juvenile otosclerosis. 4.

Effect of Cochlear Window Fixation on Air- and Bone-Conduction Thresholds

In the absence of patent cochlear windows, cochlear fluid inertia depends on the presence of a "third window" as a major component of the bone-conduction response. Studies have shown conflicting results regarding changes in air and bone conduction whenever, the round window, oval window, or both windows were occluded. The study was performed in a tertiary university-affiliated medical center. Auditory brain responses to clicks and 1-kHz tone bursts delivered by air and bone conduction were tested in 5 adult-size fat sand rats. The round window membrane (total, 7 ears) was sealed with Super Glue, and auditory brain response testing was repeated. Thereafter, the stapes footplate was firmly fixated, and auditory brain responses were recorded for a third time. Round-window fixation induced a significant increase in air-conduction thresholds to clicks from 36.4 ± 0.9 to 69.3 ± 4.1 dB SPL, with no significant change in bone-conduction thresholds. When the stapes footplate was immobilized as well, air conduction increased by another 20 dB, on average, with no change in bone conduction. A similar deterioration was seen in response to 1 kHz stimulus. These findings support and complement earlier studies in the same animal model, suggesting that when the pressure outlet through the cochlear windows are abolished, still bone conduction displaces the cochlear partition probably because of a functioning "third window."

Superior Canal Dehiscence Effect on Hearing Thresholds

Superior semicircular dehiscence syndrome is associated with vestibular symptoms and an air-bone gap component in the audiogram, apparently caused by the creation of a pathological bony "third window" in the superior semicircular canal. The aim of this study was to evaluate changes in auditory air- and bone-conduction thresholds to low- and high-frequency stimuli in an animal model of a bony fenestration facing the aerated mastoid cavity. Anatomic, audiological. Tertiary university-affiliated medical center. A small hole was drilled in the bony apical portion of the superior semicircular canal facing the mastoid bulla/cavity, with preservation of the membranous labyrinth, in 5 adult-size fat sand rats. Auditory brain stem responses to clicks and 1-kHz tone bursts delivered by air and bone conduction before surgery, after opening the bulla, and after fenestration. After fenestration, a significant air-bone gap was measured in response to clicks (mean ± standard deviation, 37 ± 5.8 dB) and bursts (mean ± standard deviation, 34 ± 14.5 dB). The gap was attributable solely to the significant deterioration in air-conduction thresholds, in the absence of a significant change in bone conduction thresholds. The pattern of auditory brain response changes closely resembled that reported for middle ear dysfunction, namely, an increase in absolute latency of waves I, III, and V without significant alterations in interpeak latency differences. Bony fenestration of the superior semicircular canal toward an aerated cavity in a rodent model mimics the auditory loss pattern of patients with superior semicircular dehiscence syndrome. The dehiscent membrane accounts for the auditory changes.

Systematic Preservation of the Ossicular Chain in Cholesteatoma Surgery Using a Fiber-Guided Laser

1. To investigate whether systematic preservation of the intact ossicular chain in cholesteatoma surgery provides better hearing than dismantling the chain and reconstructing it. 2. To determine whether systematic preservation of the ossicular chain in cholesteatoma surgery can be performed safely. Longitudinal parallel group study. District general hospital and private hospital. Adults and children who underwent primary intact canal wall cholesteatoma surgery. Group A: Laser-assisted cholesteatoma surgery resulting in an intact ossicular chain. Group B: Laser-assisted cholesteatoma surgery resulting in a disrupted chain and an ossiculoplasty onto an intact stapes superstructure. 1a. Conductive hearing loss (four frequency air-bone gap). 1b. Patient-orientated outcome (Belfast Rules of Thumb). 2a. Change in bone conduction threshold (four frequencies). 2b. Residual cholesteatoma rate. 2c. Rate of facial palsy. There were eighty ears in Group A and sixty-nine in group B.The median hearing loss for Group A is 11.44 dB HL.The median hearing loss for Group B is 15.63 dB HL. (p = 0.001). Seventy out of eighty ears in Group A and forty-six out of sixty-nine ears in Group B fulfilled the Belfast Rule of Thumb. (p = 0.002). The null hypothesis is rejected for both of the hearing outcome measures.The two groups did not significantly differ in respect of any of the risk assessment measures. The fibre-guided laser allows the cholesteatoma surgeon to preserve the ossicular chain in a systematic manner which is both safe and of benefit to the patient.

Influence of a Totally Open Oval Window on Bone Conduction in Otosclerosis

Objective: The aim of this study was to evaluate changes in bone conduction thresholds before, during and after total stapedectomy. Study Design: Prospective clinical study. Methods: In 27 ears of 26 patients undergoing stapedectomy under local anesthesia, bone conduction was measured before surgery, during surgery under open oval window conditions, and after the insertion of a steel wire connective tissue prosthesis. Statistical data analysis was performed on the audiometric results. Results: Under open oval window conditions, bone conduction hearing was found to be improved between 500 and 2000 Hz, but not at 4000 Hz. After insertion of the prosthesis, an additional improvement was evident at 500 and 1000 Hz, but a loss was seen at 2000 and 4000 Hz. Conclusion: This is the first investigation reported in which audiometry was performed under open oval window conditions during stapes surgery. Our results demonstrate that at least part of the preoperative bone conduction hearing loss in otosclerosis must be of mechanical, but not of sensorineural origin, as already suspected by Carhart. The fixed footplate suppresses cochlear micromechanics mainly at frequencies between 500 to 2000 Hz. Furthermore, the loss in bone conduction hearing at 2000 and 4000 Hz after insertion of the prosthesis indicates that rather than the surgical procedure of total removal of the footplate, other factors such as the handling of the prosthesis or its mechanical properties after insertion cause high-frequency hearing loss after stapes surgery.

Changes in bone conduction thresholds with vibrator contact area.

An experimental bone conduction vibrator was used to measure force and acceleration directly at the point of contact, the subject's forehead. Force and acceleration at threshold were measured for six subjects over a frequency range of 250 to 6000 Hz and over a contact area range of five to one. These measurements suggest that for any test subject, the variation in force of threshold with contact area is much smaller than the corresponding variation in acceleration at threshold.

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.

CHANGES IN BONE-CONDUCTION THRESHOLDS PRODUCED BY MASKING IN THE NON-TEST EAR.

Two experiments were conducted to determine the effects of central masking on both air and bone-conduction thresholds. In the first investigation, 10 normal listeners were tested by air conduction and by bone conduction via the mastoid process and the frontal bone as various levels of narrow-band noise were presented to the contralateral ear. Generally, as the noise level increased, there was a small but gradual increase in the threshold on the test ear. However, the threshold shift for frontal bone measurements was always greater than comparable air-conduction or bone-conduction thresholds from the mastoid process. The additional shift in threshold for frontal bone measurements may have been the result of changing from binaural stimulation in quiet to monaural stimulation during the masking conditions. This proposition was investigated in Experiment II. The test ears of 6 subjects were occluded with plugs which induced an appreciable increase in bone-conduction sensitivity. Thus, the frontal bone threshold as well as the mastoid threshold was monaural, even in the quiet condition. If the above proposition were correct, it was predicted that identical shifts in threshold due to central masking would be found for frontal bone measurements as for mastoid measurements. The threshold shifts for air conduction and bone conduction via mastoid or frontal bone vibrator placements were found to be similar.