Audiologic Characteristics Of The Patient With Otosclerosis

Acoustic Reflex Screening of Conductive Hearing Loss for Third Window Disorders

Objective

This study examines the effectiveness of acoustic reflexes in screening for third window disorders (eg, superior semicircular canal dehiscence) prior to middle ear exploration for conductive hearing loss.

Study Design

Case series with chart review.

Setting

Outpatient tertiary otology center.

Subjects and Methods

A review was performed of 212 ears with acoustic reflexes, performed as part of the evaluation of conductive hearing loss in patients without evidence of chronic otitis media. The etiology of hearing loss was determined from intraoperative findings and computed tomography imaging. The relationship between acoustic reflexes and conductive hearing loss etiology was assessed.

Results

Eighty-eight percent of ears (166 of 189) demonstrating absence of all acoustic reflexes had an ossicular etiology of conductive hearing loss. Fifty-two percent of ears (12 of 23) with at least 1 detectable acoustic reflex had a nonossicular etiology. The positive and negative predictive values for an ossicular etiology were 89% and 57% when acoustic reflexes were used alone for screening, 89% and 39% when third window symptoms were used alone, and 94% and 71% when reflexes and symptoms were used together, respectively.

Conclusion

Acoustic reflex testing is an effective means of screening for third window disorders in patients with a conductive hearing loss. Questioning for third window symptoms should complement screening. The detection of even 1 acoustic reflex or third window symptom (regardless of reflex status) should prompt further workup prior to middle ear exploration.

Contribution of Vestibular-Evoked Myogenic Potential (VEMP) testing in the assessment and the differential diagnosis of otosclerosis

Background

The aim of this prospective clinical study was to evaluate the clinical importance of Vestibular-Evoked Myogenic Potentials (VEMPs) in the assessment and differential diagnosis of otosclerosis and otologic diseases characterized by “pseudo-conductive” components. We also investigated the clinical appearance of balance disorders in patients with otosclerosis by correlating VEMP results with the findings of caloric testing and pure tone audiometry(PTA).

Material/Methods

Air-conducted(AC) 4-PTA, bone-conducted(BC) 4-PTA, air-bone Gap(ABG), AC, BC tone burst evoked VEMP, and calorics were measured preoperatively in 126 otosclerotic ears.

Results

The response rate of the AC-VEMPs and BC-VEMPs was 29.36% and 44.03%, respectively. Statistical differences were found between the means of ABG, AC 4-PTA, and BC 4-PTA in the otosclerotic ears in relation to AC-VEMP elicitability. About one-third of patients presented with disequilibrium. A statistically significant interaction was found between calorics and dizziness in relation to PTA thresholds. No relationship was found between calorics and dizziness with VEMPs responses.

Conclusions

AC and BC VEMPs can be elicited in ears with otosclerosis. AC-VEMP is more vulnerable to conductive hearing loss. Evaluation of AC-VEMP thresholds can be added in the diagnostic work-up of otosclerosis in case of doubt, enhancing differential diagnosis in patients with air-bone gaps. Otosclerosis is not a cause of canal paresis or vertigo.

New aspects in the clinical diagnosis of otosclerosis using laser Doppler vibrometry

HYPOTHESIS

Laser Doppler vibrometry (LDV) applied to umbo motion measurement in healthy and otosclerotic ears shows statistically tested differences.

BACKGROUND

The LDV is a research tool that measures middle ear function by registering sound-induced tympanic membrane velocity. Its possible application in the diagnosis of different middle ear disorders, especially otosclerosis, is currently being evaluated. Established diagnosis can identify various ossicular chain pathologies in most cases but is still sometimes contradicted by the findings of surgical middle ear exploration.

METHODS

We used a fractionally modified LDV setting as previously reported to evaluate 150 normal-hearing ears and 49 ears with conductive hearing loss. In a first step, the impact of age variation on the umbo transfer function was investigated by dividing the normal-hearing population into 3 age groups. In a second step, the control group was compared with patients with conductive hearing loss; certain patterns in the umbo transfer function were especially investigated by discriminant analysis.

RESULTS

Mean magnitude of the oldest group was found to be significantly higher than the other 2 groups, but it was not possible to diagnostically classify the 3 groups. Discriminant analysis revealed the linear term of a cubic polynom to significantly best describe the umbo transfer function in normal ears (p < 0.0005; partial eta = 0.866) and in otosclerotic ears (p < 0.0005; partial eta = 0.799). Separating otosclerotic ear from normal-hearing ear evidence suggests a sensitivity of 82% and specificity of 92%.

CONCLUSION

Evaluation of LDV magnitude curve patterns gives helpful information in the diagnosis of otosclerosis but does not suffice as a single diagnostic tool.

High-resolution computed tomography in the diagnosis of otosclerosis in Taiwan

BACKGROUND

Otosclerosis is rare in Asians, and the clinical role of imaging remains controversial. We sought to clarify the tomographic findings of otosclerosis in Taiwanese patients and determine the value and necessity of high-resolution computed tomography (HRCT) of the temporal bone in diagnosing the disease in Taiwan.

METHODS

This retrospective study enrolled 22 patients (24 ears) with clinically, surgically and pathologically confirmed otosclerosis. All subjects underwent HRCT of the temporal bone; the images were then reviewed at workstations. The control group consisted of 15 patients.

RESULTS

HRCT was positive in 46% of the clinically, surgically and pathologically confirmed otosclerotic ears. Patients with a positive imaging study had a smaller preoperative air-bone gap and a significantly shorter duration of the disease. The duration of the disease also tended to be greater in patients with a larger preoperative air-bone gap.

CONCLUSION

HRCT has high specificity (100%) but low sensitivity (46%) for the diagnosis of otosclerosis in Taiwanese patients despite progress in radiology. The low image positive rate we found, compared with that in Western literature, may stem from a greater percentage of inactive otosclerosis.

Hearing results of 1145 stapedotomies evaluated with Amsterdam hearing evaluation plots

Aims:

To evaluate the hearing results of a large series of primary stapedotomies, according to American Academy of Otolaryngology, Head and Neck Surgery guidelines and Amsterdam hearing evaluation plots.

Study design:

Retrospective chart review.

Methods:

The charts for 1369 consecutive stapedotomy cases were reviewed; 1145 cases of primary stapedotomy were included. Raw data from the audiometric database were evaluated using Amsterdam hearing evaluation plots. The effect on outcomes of using different audiological parameters was analysed.

Results:

A significant improvement was demonstrated in mean post-operative air conduction and speech reception thresholds, with no change in bone conduction. Air–bone gap closure of 10 dB or more was achieved in 82 per cent of cases. A ‘dead ear’ occurred in one patient (0.1 per cent).

Conclusion:

This study reports the largest series of primary stapedotomies evaluated with Amsterdam hearing evaluation plots. This method enables visual identification of successful and unfavourable results, providing more accurate and detailed presentation of surgical outcomes.

Another cause for conductive hearing loss with present acoustic reflexes

There are numerous potential causes of conductive hearing loss (HL). It is important to obtain a thorough history and perform a complete examination, including audiometric testing and radiographic evaluation when necessary. In this report, we present a patient with an intact tympanic membrane, no history of ear disease or trauma who as an adult developed progressive, conductive HL because of an anomalous course of a dehiscent facial nerve. In the patient with a conductive HL and at least partially intact reflexes, superior semicircular canal dehiscence, fracture of the stapes superstructure proximal to the tendon, other third window phenomena, and now dehiscence of the facial nerve resulting in decreased mobility of the ossicular chain must be considered.

Vestibular-Evoked Myogenic Potentials in Patients With Otosclerosis Using Air- and Bone-Conducted Tone-Burst Stimulation

OBJECTIVE

Otosclerosis is a progressive disease with a remodeling process causing ossicular malformation and conductive hearing loss. The aim of this study was to investigate whether vestibular-evoked myogenic potential (VEMP) correlates with the progression of otosclerosis.

DESIGN

Fifteen patients with otosclerosis (21 ears) without operation and 10 healthy subjects (20 ears) underwent VEMP test using air-conducted (AC) and bone-conducted (BC) tone-burst stimulation.

SETTING

Tertiary referral university hospital.

RESULTS

In 21 unoperated otosclerotic ears, 5 ears (24%) showed present AC-VEMPs, and 16 ears had absent AC-VEMPs. Conversely, 16 ears (76%) displayed present BC-VEMPs and 5 ears with absent BC-VEMPs. In those with both AC- and BC-VEMPs, none of them showed air-bone gap greater than 30 dB; in those with absent AC-VEMPs but present BC-VEMPs, 27% of the ears had air-bone gap greater than 30 dB; and in those with absence of both AC- and BC-VEMPs, 80% of the ears revealed air-bone gap greater than 30 dB. Thus, a significant relationship existed among the presence of AC-VEMPs, BC-VEMPs, and magnitude of conductive hearing loss.

CONCLUSION

The presence of an AC-VEMP may indicate an earlier stage of otosclerosis, although absent BC-VEMP infers a later stage. Restated, AC-VEMPs may complement the results obtained with BC-VEMPs to classify the stage of otosclerosis.

Exploratory tympanotomy revealing incus discontinuity and stapedial otosclerosis as a cause of conductive hearing loss

OBJECTIVE

To describe a unilateral progressive conductive hearing loss caused by incus discontinuity (without erosion of the long process of the incus), and otosclerosis with fixation of the stapedial footplate.

STUDY DESIGN

Case report.

SETTING

Department of Otolaryngology, Head and Neck Surgery of the University of Rochester Medical Center, which is a regional tertiary referral center.

PATIENT

A 54-year-old woman with multiple otologic complaints including tympanic membrane perforations, otalgia, tinnitus, and hearing loss. Audiography demonstrated 100% speech discrimination bilaterally and a significant conductive right-sided hearing loss.

INTERVENTION

The patient underwent a stapedectomy, during which a discontinuity between the long process of the incus and the stapes with no bony erosion was identified. The stapedectomy was completed and an ossicular piston prosthesis was inserted to reestablish ossicular continuity with the tympanic membrane.

MAIN OUTCOME MEASURE

Improved subjective hearing confirmed objectively by audiography.

CONCLUSION

This is the third reported case of an unusual combination of otosclerosis and ossicular discontinuity, and the first such case report in a patient without head trauma. In addition, it adds a unique item to the differential diagnosis of the pathologic features implicated in an ear with a conductive deficit and normal tympanogram.

Superior semicircular canal dehiscence presenting as conductive hearing loss without vertigo

OBJECTIVE

The objective of this study was to describe superior semicircular canal dehiscence (SSCD) presenting as otherwise unexplained conductive hearing loss without vestibular symptoms.

STUDY DESIGN

Retrospective.

SETTING

Tertiary referral center.

PATIENTS

The study comprised 8 patients (10 ears), 5 males and 5 females aged 27 to 59 years. All 10 ears had SSCD on high-resolution computed tomography scan of the temporal bone. DIAGNOSTIC TESTS AND RESULTS: All 10 ears had significant conductive hearing loss. The air-bone gaps were largest in the lower frequencies at 250, 500, and 1000 Hz; the mean gaps for these 3 frequencies for the 10 ears were 49, 37, and 35 dB, respectively. Bone-conduction thresholds below 2000 Hz were negative (-5 dB to -15 dB) at one or more frequencies in 8 of the 10 ears. There were no middle ear abnormalities to explain the air-bone gaps in these 10 ears. Computed tomography scan and laboratory testing indicated lack of middle ear pathology; acoustic reflexes were present, vestibular evoked myogenic potentials (VEMPs) were present with abnormally low thresholds, and umbo velocity measured by laser Doppler vibrometry was above mean normal. Middle ear exploration was negative in six ears; of these six, stapedectomy had been performed in three ears and ossiculoplasty in two ears, but the air-bone gap was unchanged postoperatively. The data are consistent with the hypothesis that the SSCD introduced a third mobile window into the inner ear, which in turn produced the conductive hearing loss by 1) shunting air-conducted sound away from the cochlea, thus elevating air-conduction thresholds; and 2) increasing the difference in impedance between the oval and round windows, thus improving thresholds for bone-conducted sound.

CONCLUSION

SSCD can present with a conductive hearing loss that mimics otosclerosis and could explain some cases of persistent conductive hearing loss after uneventful stapedectomy. Audiometric testing with attention to absolute bone-conduction thresholds, acoustic reflex testing, VEMP testing, laser vibrometry of the umbo, and computed tomograph scanning can help to identify patients with SSCD presenting with conductive hearing loss without vertigo.

Dehiscence of bone overlying the superior canal as a cause of apparent conductive hearing loss

OBJECTIVE

To identify patients with superior semicircular canal dehiscence and apparent conductive hearing loss and to define the cause of the air-bone gap.

STUDY DESIGN

Prospective study of patients with superior canal dehiscence. SETTING Tertiary referral center.

PATIENTS

Vestibular and/or auditory findings indicative of canal dehiscence and demonstration of superior canal dehiscence on computed tomography of the temporal bone.

INTERVENTION

Vestibular-evoked myogenic potentials, three-dimensional eye movement recordings, and surgical resurfacing of the superior canal.

OUTCOME MEASURE

Association of superior canal dehiscence with an air-bone gap on audiometry.

RESULTS

Four patients with dehiscence of bone overlying the superior canal were found to have air-bone gaps in the affected ears that were greatest at lower frequencies and averaged 24 +/- 7 dB over the frequency range of 250 to 4,000 Hz. Three of these patients had undergone stapedectomy before the identification of superior canal dehiscence. The air-bone gap was unchanged postoperatively. Each patient had an intact vestibular-evoked myogenic potential (VEMP) response from the affected ear, a finding that would not have been expected based on a middle ear cause of conductive hearing loss. One patient underwent resurfacing of the superior canal through a middle fossa approach. Postoperatively, his vestibular symptoms were relieved, and his air conduction thresholds were improved by 20 dB.

CONCLUSIONS

Superior canal dehiscence can result in apparent conductive hearing loss. The third mobile window created by the dehiscent superior canal results in dissipation of acoustic energy and is a cause of inner ear conductive hearing loss.

Dehiscence of bone overlying the superior canal as a cause of apparent conductive hearing loss

OBJECTIVE

To identify patients with superior semicircular canal dehiscence and apparent conductive hearing loss and to define the cause of the air-bone gap.

STUDY DESIGN

Prospective study of patients with superior canal dehiscence. SETTING Tertiary referral center.

PATIENTS

Vestibular and/or auditory findings indicative of canal dehiscence and demonstration of superior canal dehiscence on computed tomography of the temporal bone.

INTERVENTION

Vestibular-evoked myogenic potentials, three-dimensional eye movement recordings, and surgical resurfacing of the superior canal.

OUTCOME MEASURE

Association of superior canal dehiscence with an air-bone gap on audiometry.

RESULTS

Four patients with dehiscence of bone overlying the superior canal were found to have air-bone gaps in the affected ears that were greatest at lower frequencies and averaged 24 +/- 7 dB over the frequency range of 250 to 4,000 Hz. Three of these patients had undergone stapedectomy before the identification of superior canal dehiscence. The air-bone gap was unchanged postoperatively. Each patient had an intact vestibular-evoked myogenic potential (VEMP) response from the affected ear, a finding that would not have been expected based on a middle ear cause of conductive hearing loss. One patient underwent resurfacing of the superior canal through a middle fossa approach. Postoperatively, his vestibular symptoms were relieved, and his air conduction thresholds were improved by 20 dB.

CONCLUSIONS

Superior canal dehiscence can result in apparent conductive hearing loss. The third mobile window created by the dehiscent superior canal results in dissipation of acoustic energy and is a cause of inner ear conductive hearing loss.

Histologic changes on stapedial footplate in otosclerosis. Correlations between histologic activity and clinical findings

OBJECTIVE

To quantify the relationship between the stage of histologic changes of the stapedial footplate in otosclerosis and the magnitude of preoperative hearing loss, tinnitus, vestibular disorder, and postoperative improvement of hearing.

STUDY DESIGN

Retrospective case review.

SETTING

Tertiary referral center.

PATIENTS

The study included 97 patients (ears) (69 female and 28 male patients), with conductive or mixed hearing loss who were operated on for otosclerosis. The criterion for including a patient in the study was otosclerosis established by tympanoscopy and confirmed by histologic examination of a piece of the stapedial footplate.

MAIN OUTCOME MEASURES

By the histologic features of the stapedial footplate fragments, the stage of the otosclerotic lesion was classified as spongiotic, fibrotic, or sclerotic. The patients were carefully matched for sex, age, duration of hearing impairment, presence of tinnitus, and vestibular symptoms. Preoperative and postoperative air-conduction and bone-conduction thresholds were calculated as an average of four frequencies (0.5, 1, 2, and 4 kHz). Analysis was subsequently carried out on the preoperative and postoperative air-bone gap and bone-conduction threshold improvement.

RESULTS

With regard to the histologic stage of otosclerotic lesions, tinnitus and vestibular disorders were present more frequently in patients with the sclerotic type of lesion. The type of otosclerotic lesion had no significant influence on the mean preoperative air-conduction threshold, bone-conduction threshold, and air-bone gap or on postoperative air-conduction threshold and bone-conduction threshold, but the postoperative air-bone gap was higher in patients with the fibrotic type of otosclerotic lesion and was highest in patients with the spongiotic type of otosclerotic lesion (p < 0.01).

CONCLUSIONS

Tinnitus, vestibular disorders, and better postoperative closure of the air-bone gap are present more frequently in patients with a sclerotic type of otosclerotic lesion on the stapedial footplate.

Middle ear dynamic characteristics in patients with otosclerosis

OBJECTIVE

To investigate the middle ear dynamic characteristics in patients with otosclerosis using the sweep frequency impedance meter (SFI test) and conventional tympanometry, and also to evaluate the diagnostic efficiency of the SFI test for otosclerosis.

DESIGN

The study was designed to collect a total of 25 (36 ears) consecutive patients with otosclerosis. All subjects followed a clinical protocol, which consisted of a hearing problem questionnaire, otoscopic examination, and audiometric measurements. These included pure tone audiometry, conventional tympanometry, and SFI test.

RESULTS

In the SFI test, the middle ear dynamic characteristics were measured in terms of the resonance frequency and middle ear mobility. Three distinct categories of middle ear dynamic characteristics were found in patients with otosclerosis, i.e., high stiffness, normal stiffness, and low stiffness middle ear status. On comparison of the results of SFI with conventional tympanometry, a significantly higher percentage of abnormal stiffness was found when using the SFI test than that when using conventional tympanometry.

CONCLUSIONS

The present findings confirm the advantage of the SFI test over conventional tympanometry in detecting middle ear status and mechanics in patients with otosclerosis. Moreover, different middle ear dynamic characteristics in patients with otosclerosis are most likely to be related to the different stages of the pathological changes.

Fluoride therapy for cochlear otosclerosis? an audiometric and computerized tomography evaluation

The progress of sensorineural hearing loss (SNHL) in patients with cochlear otosclerosis was compared for 19 patients treated with fluoride for 1-5 years and 22 untreated controls. CT scans of eight patients before and after fluoride treatment were evaluated visually. Fluoride therapy arrested the progression of SNHL in the low (250, 500 and 1,000 Hz) (p < 0.001) and high (2 and 4 kHz) (p = 0.008) frequencies. It seemed to be more effective for the higher frequencies in cases with an initial SNHL of < 50 dB. Fluoride administration for 4 years did not seem to be superior to a shorter treatment period (1-2 years). For six patients followed up after discontinuing fluoride therapy there was minimal deterioration in SNHL. There was no clear relationship between the size and site of otospongiotic lesions on CT and the severity of SNHL. Follow-up with CT evaluation did not provide reliable information as to the efficacy of fluoride therapy.

Correlations between pathologic changes in the stapes and conductive hearing loss in otosclerosis

The goal of this temporal bone study was to quantify the relationship between specific histologic changes at the stapes footplate and the magnitude of the air-bone gap in otosclerosis. The study material comprised 26 specimens with otosclerosis and 37 age-matched controls. Detailed anatomic measurements were made on each histologic section through the stapes footplate in each bone, resulting in 30 different measurement parameters for each bone. For frequencies 250 to 2,000 Hz, the conductive hearing loss correlated highly with (p < .01) and appeared to be caused primarily by narrowing and loss of the annular ligament, especially at the posterior stapediovestibular joint space. The size of the air-bone gap appeared to be determined by the extent and degree of this pathologic change. Schuknecht's hypothesis that bony ankylosis of the footplate would be associated with an air-bone gap of >30 dB was supported by our data. However, the degree and extent of bony footplate ankylosis could not be reliably predicted by the size of the air-bone gap.