51
|
Investigation of the mechanics of Type III stapes columella tympanoplasty using laser-Doppler vibrometry. Otol Neurotol 2007; 28:782-7. [PMID: 17948356 DOI: 10.1097/mao.0b013e31811f40fb] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVES To investigate the middle ear mechanics of Type III stapes columella tympanoplasty using laser-Doppler vibrometry (LDV) and to determine whether LDV was useful in the identification of structural factors responsible for poor hearing outcomes. BACKGROUND The Type III stapes columella tympanoplasty procedure involves placing a tympanic membrane (TM) graft directly onto the stapes head. Postoperative hearing results vary widely, with air-bone gaps (ABGs) ranging from 10 to 60 dB. METHODS Laser-Doppler vibrometry measurements were performed in 22 patients (23 ears) who underwent Type III stapes columella tympanoplasty. The measurements were made at three locations on the TM graft: over the stapes head, over the round window, and on the anterior TM. The LDV results were correlated with the clinical and audiologic findings. RESULTS The 23 ears were divided into three groups: Nonaerated ears (n = 2). The ABGs were 30 to 60 dB. The TM velocities over all three locations were 20 to 40 dB lower than normal umbo velocity (in normally hearing subjects). Fixed stapes with aerated middle ear (n = 2). The ABGs were 40 to 60 dB, and TM velocities were equivalent to normal umbo velocity in one case and lower by 15 to 20 dB in another case. Mobile stapes and aerated middle ear (n = 19). There were two subgroups in this category: 1) small ABGs less than 25 dB (n = 7) and large gaps greater than or equal to 25 dB (n = 12). There were small differences in TM graft velocity at all three measurement locations between these two subgroups. However, these small differences did not explain the large difference in ABG between the two subgroups. CONCLUSION Nonaeration of the middle ear and stapes fixation lead to large residual conductive hearing losses after Type III tympanoplasty. Laser-Doppler vibrometry can aid in the diagnosis of nonaeration of the middle ear but does not readily diagnose stapes fixation. Postoperative results can vary even in cases of a mobile stapes and an aerated middle ear. We hypothesize that these variations may be the result of differences in the coupling between the TM graft and the stapes head. Measurements of TM velocities by means of LDV did not show clear differences between cases with good hearing and cases with poor hearing in ears with a mobile stapes and an aerated ear. Except for diagnosis of nonaeration of the middle ear, LDV seems to have limited clinical usefulness to identify causes of failure after Type III tympanoplasty.
Collapse
|
52
|
Merchant SN, Nakajima HH, Halpin C, Nadol JB, Lee DJ, Innis WP, Curtin H, Rosowski JJ. Clinical investigation and mechanism of air-bone gaps in large vestibular aqueduct syndrome. Ann Otol Rhinol Laryngol 2007; 116:532-41. [PMID: 17727085 PMCID: PMC2585521 DOI: 10.1177/000348940711600709] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
OBJECTIVES Patients with large vestibular aqueduct syndrome (LVAS) often demonstrate an air-bone gap at the low frequencies on audiometric testing. The mechanism causing such a gap has not been well elucidated. We investigated middle ear sound transmission in patients with LVAS, and present a hypothesis to explain the air-bone gap. METHODS Observations were made on 8 ears from 5 individuals with LVAS. The diagnosis of LVAS was made by computed tomography in all cases. Investigations included standard audiometry and measurements of umbo velocity by laser Doppler vibrometry (LDV) in all cases, as well as tympanometry, acoustic reflex testing, vestibular evoked myogenic potential (VEMP) testing, distortion product otoacoustic emission (DPOAE) testing, and middle ear exploration in some ears. RESULTS One ear with LVAS had anacusis. The other 7 ears demonstrated air-bone gaps at the low frequencies, with mean gaps of 51 dB at 250 Hz, 31 dB at 500 Hz, and 12 dB at 1,000 Hz. In these 7 ears with air-bone gaps, LDV showed the umbo velocity to be normal or high normal in all 7; tympanometry was normal in all 6 ears tested; acoustic reflexes were present in 3 of the 4 ears tested; VEMP responses were present in all 3 ears tested; DPOAEs were present in 1 of the 2 ears tested, and exploratory tympanotomy in 1 case showed a normal middle ear. The above data suggest that an air-bone gap in LVAS is not due to disease in the middle ear. The data are consistent with the hypothesis that a large vestibular aqueduct introduces a third mobile window into the inner ear, which can produce an air-bone gap by 1) shunting air-conducted sound away from the cochlea, thus elevating air conduction thresholds, and 2) increasing the difference in impedance between the scala vestibuli side and the scala tympani side of the cochlear partition during bone conduction testing, thus improving thresholds for bone-conducted sound. CONCLUSIONS We conclude that LVAS can present with an air-bone gap that can mimic middle ear disease. Diagnostic testing using acoustic reflexes, VEMPs, DPOAEs, and LDV can help to identify a non-middle ear source for such a gap, thereby avoiding negative middle ear exploration. A large vestibular aqueduct may act as a third mobile window in the inner ear, resulting in an air-bone gap at low frequencies.
Collapse
Affiliation(s)
- Saumil N Merchant
- Massachusetts Eye and Ear Infirmary, Department of Otolaryngology, 243 Charles St, Boston, MA 02114, USA
| | | | | | | | | | | | | | | |
Collapse
|
53
|
Dai C, Wood MW, Gan RZ. Tympanometry and laser Doppler interferometry measurements on otitis media with effusion model in human temporal bones. Otol Neurotol 2007; 28:551-8. [PMID: 17529855 DOI: 10.1097/mao.0b013e318033f008] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
HYPOTHESIS The aim of this study is to investigate the effect of middle ear fluid and pressure on tympanic membrane mobility by using laser Doppler interferometry and to compare these results with tympanometry. BACKGROUND Tympanometry has been commonly used for evaluation of otitis media with effusion, a middle ear disease with fluid in the cavity. However, this test lacks specific interpretations of middle ear disorders based on tympanometric data. Laser interferometry, as an advanced research tool to measure middle ear function, may provide knowledge of how tympanic membrane mobility is affected by middle ear fluid and pressure. METHODS An otitis media with effusion model was created in seven human temporal bones for conducting experiments with tympanometry and laser interferometry. Middle ear pressure varied from -20 to +20 cm water, and the amount of fluid in the middle ear was gradually increased to fill the cavity. RESULTS The displacement of the tympanic membrane measured by laser interferometry at selected frequencies decreased significantly corresponding to the middle ear air pressure changes. Tympanometry detected middle ear pressure by the change of tympanometric peak location, but the tympanogram shape was not affected by the middle ear pressure. The middle ear fluid was detected by tympanometry with as little as 0.3 mL, and laser interferometry was able to measure the displacement change of the tympanic membrane with 0.2 or 0.3 mL fluid at different frequencies. CONCLUSION Laser interferometry can detect the effect of middle ear pressure and fluid on tympanic membrane movement as well as tympanometry does.
Collapse
Affiliation(s)
- Chenkai Dai
- University of Oklahoma, Norman, Oklahoma, USA
| | | | | |
Collapse
|
54
|
Merchant SN, Rosowski JJ, McKenna MJ. Superior semicircular canal dehiscence mimicking otosclerotic hearing loss. Adv Otorhinolaryngol 2007; 65:137-145. [PMID: 17245035 PMCID: PMC2636720 DOI: 10.1159/000098790] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A puzzling aspect of middle ear surgery is the presence of an air-bone gap in a small number of cases with no apparent cause. We believe that some of these cases are due to unrecognized superior semicircular canal dehiscence (SSCD). We have now gathered experience from 20 patients with SSCD presenting with apparent conductive hearing loss without vestibular symptoms. All affected ears had SSCD on high-resolution CT scan. The common findings in these patients were: (1) the air-bone gaps occurred in the lower frequencies below 2,000 Hz, and ranged from 10 to 60 dB; (2) bone conduction thresholds below 2,000 Hz were sometimes negative (-5 dB to -15 dB); (3) the acoustic (stapedial) reflex was present; (4) measurement of umbo velocity by laser Doppler vibrometry showed slight hypermobility of umbo motion; (5) the vestibular-evoked myogenic potential response was present, with thresholds that were abnormally low, and (6) the middle ear was normal at exploratory tympanotomy, including normal mobility of the ossicles and a patent round window niche. We have investigated the mechanism of the air-bone gap due to SSCD using a theoretical framework, clinical research data and an animal model (chinchilla). Our research supports the hypothesis that SSCD introduces a 'third' window into the inner ear which produces the airbone gap by (1) shunting air-conducted sound away from the cochlea, thus elevating air conduction thresholds, and (2) increasing the difference in impedance between the scala tympani and scala vestibuli, thus improving thresholds for bone-conducted sound.
Collapse
Affiliation(s)
- Saumil N. Merchant
- Department of Otology and Laryngology, Harvard Medical School, Massachusetts Institute of Technology, Cambridge, Mass., USA
- Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts Institute of Technology, Cambridge, Mass., USA
- Division of Speech and Hearing Science Technology, Massachusetts Institute of Technology, Cambridge, Mass., USA
| | - John J. Rosowski
- Department of Otology and Laryngology, Harvard Medical School, Massachusetts Institute of Technology, Cambridge, Mass., USA
- Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts Institute of Technology, Cambridge, Mass., USA
- Division of Speech and Hearing Science Technology, Massachusetts Institute of Technology, Cambridge, Mass., USA
| | - Michael J. McKenna
- Department of Otology and Laryngology, Harvard Medical School, Massachusetts Institute of Technology, Cambridge, Mass., USA
- Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts Institute of Technology, Cambridge, Mass., USA
- Division of Speech and Hearing Science Technology, Massachusetts Institute of Technology, Cambridge, Mass., USA
| |
Collapse
|
55
|
Chien W, Ravicz ME, Rosowski JJ, Merchant SN. Measurements of human middle- and inner-ear mechanics with dehiscence of the superior semicircular canal. Otol Neurotol 2007; 28:250-7. [PMID: 17255894 PMCID: PMC2585995 DOI: 10.1097/01.mao.0000244370.47320.9a] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES (1) To develop a cadaveric temporal-bone preparation to study the mechanism of hearing loss resulting from superior semicircular canal dehiscence (SCD) and (2) to assess the potential usefulness of clinical measurements of umbo velocity for the diagnosis of SCD. BACKGROUND The syndrome of dehiscence of the superior semicircular canal is a clinical condition encompassing a variety of vestibular and auditory symptoms, including an air-bone gap at low frequencies. It has been hypothesized that the dehiscence acts as a "third window" into the inner ear that shunts acoustic energy away from the cochlea at low frequencies, causing hearing loss. METHODS Sound-induced stapes, umbo, and round-window velocities were measured in prepared temporal bones (n = 8) using laser-Doppler vibrometry (1) with the superior semicircular canal intact, (2) after creation of a dehiscence in the superior canal, and (3) with the dehiscence patched. Clinical measurements of umbo velocity in live SCD ears (n = 29) were compared with similar data from our cadaveric temporal-bone preparations. RESULTS An SCD caused a significant reduction in sound-induced round-window velocity at low frequencies, small but significant increases in sound-induced stapes and umbo velocities, and a measurable fluid velocity inside the dehiscence. The increase in sound-induced umbo velocity in temporal bones was also found to be similar to that measured in the 29 live ears with SCD. CONCLUSION Findings from the cadaveric temporal-bone preparation were consistent with the third-window hypothesis. In addition, measurement of umbo velocity in live ears is helpful in distinguishing SCD from other otologic pathologies presenting with an air-bone gap (e.g., otosclerosis).
Collapse
Affiliation(s)
- Wade Chien
- Eaton-Peabody Laboratory, Massachusetts Eye & Ear Infirmary, Boston, USA.
| | | | | | | |
Collapse
|
56
|
Hato N, Kohno H, Okada M, Hakuba N, Gyo K, Iwakura T, Tateno M. A new tool for testing ossicular mobility during middle ear surgery: preliminary report of four cases. Otol Neurotol 2007; 27:592-5. [PMID: 16868506 DOI: 10.1097/01.mao.0000226298.36327.3d] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE We developed an ossicular vibration tester for the objective and quantitative assessment of ossicular mobility, which is one of the most critical factors affecting postoperative hearing after tympanoplasty. METHODS Our device consists of three components: a probe shaft with a curved tip to be attached to the target ossicle, a vibration exciter to activate the probe, and a piezoelectric sensor to detect vibrations of the probe. These components are encased in a stainless steel holder, allowing easy hand manipulation during ear surgery. The probe is activated with an electric signal at around 1,600 Hz. The system is controlled with a laptop computer, and the results are presented as the ratio of the ossicular resistance (ROR) to a reference value as a percentage. One measurement takes 10 ms. The device was applied in four selected patients during ear surgery. RESULTS Several measurements in two of the cochlear implantees showed a greater difference in the RORs of the stapes (15-20% in Case 1 and 35-45% in Case 2), whereas the RORs of the malleus and incus were within the same range. This was thought to correspond to the partial cochlear calcification noted in Case 2. In Case 3, who underwent surgery because of otosclerosis, the ROR of the stapes was high, ranging from 70 to 80%. When measured for the malleus-incus fixation anomaly (Case 4), the ROR of the malleus and incus was in the range of 60 to 70%. Owing to the limited surgical view, the ROR of the stapes could not be measured. No problems related to the measurements with this device were noted. CONCLUSION The design, principles, measuring procedures, and preliminary results of our new tool for testing ossicular mobility are reported. Measuring the ossicular mobility during surgery may provide important information for deciding the surgical procedures.
Collapse
Affiliation(s)
- Naohito Hato
- Department of Otolaryngology, Ehime University School of Medicine, Ehime, Japan.
| | | | | | | | | | | | | |
Collapse
|
57
|
Dalhoff E, Turcanu D, Zenner HP, Gummer AW. Distortion product otoacoustic emissions measured as vibration on the eardrum of human subjects. Proc Natl Acad Sci U S A 2007; 104:1546-51. [PMID: 17242353 PMCID: PMC1780065 DOI: 10.1073/pnas.0610185103] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
It has previously not been possible to measure eardrum vibration of human subjects in the region of auditory threshold. It is proposed that such measurements should provide information about the status of the mechanical amplifier in the cochlea. It is this amplifier that is responsible for our extraordinary hearing sensitivity. Here, we present results from a laser Doppler vibrometer that we designed to noninvasively probe cochlear mechanics near auditory threshold. This device enables picometer-sized vibration measurements of the human eardrum in vivo. With this sensitivity, we found the eardrum frequency response to be linear down to at least a 20-dB sound pressure level (SPL). Nonlinear cochlear amplification was evaluated with the cubic distortion product of the otoacoustic emissions (DPOAEs) in response to sound stimulation with two tones. DPOAEs originate from mechanical nonlinearity in the cochlea. For stimulus frequencies, f1 and f2, with f2/f1 = 1.2 and f2 = 4-9.5 kHz, and intensities L1 and L2, with L1 = 0.4L(2) + 39 dB and L2 = 20-65 dB SPL, the DPOAE displacement amplitudes were no more than 8 pm across subjects (n = 20), with hearing loss up to 16 dB. DPOAE vibration was nonlinearly dependent on vibration at f2. The dependence allowed the hearing threshold to be estimated objectively with high accuracy; the standard deviation of the threshold estimate was only 8.6 dB SPL. This device promises to be a powerful tool for differentially characterizing the mechanical condition of the cochlea and middle ear with high accuracy.
Collapse
Affiliation(s)
- E. Dalhoff
- Department of Otolaryngology, Tübingen Hearing Research Centre, Section of Physiological Acoustics and Communication, University of Tübingen, Elfriede-Aulhorn-Strasse 5, 72076 Tübingen, Germany
| | - D. Turcanu
- Department of Otolaryngology, Tübingen Hearing Research Centre, Section of Physiological Acoustics and Communication, University of Tübingen, Elfriede-Aulhorn-Strasse 5, 72076 Tübingen, Germany
| | - H.-P. Zenner
- Department of Otolaryngology, Tübingen Hearing Research Centre, Section of Physiological Acoustics and Communication, University of Tübingen, Elfriede-Aulhorn-Strasse 5, 72076 Tübingen, Germany
| | - A. W. Gummer
- Department of Otolaryngology, Tübingen Hearing Research Centre, Section of Physiological Acoustics and Communication, University of Tübingen, Elfriede-Aulhorn-Strasse 5, 72076 Tübingen, Germany
- *To whom correspondence should be addressed. E-mail:
| |
Collapse
|
58
|
Gan RZ, Dai C, Wood MW. Laser interferometry measurements of middle ear fluid and pressure effects on sound transmission. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2006; 120:3799-810. [PMID: 17225407 DOI: 10.1121/1.2372454] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
An otitis media with effusion model in human temporal bones with two laser vibrometers was created in this study. By measuring the displacement of the stapes from the medial side of the footplate, the transfer function of the middle ear, which is defined as the displacement transmission ratio (DTR) of the tympanic membrane to footplate, was derived under different middle ear pressure and fluid in the cavity with a correction factor for cochlear load. The results suggest that the DTR increases with increasing frequency up to 4k Hz when the middle ear pressure was changing from 0 to 20 or -20 cm H20 (e.g., +/-196 daPa) and fluid level was increasing from 0 to a full middle ear cavity. The positive and negative pressures show different effects on the DTR. The effect of fluid on DTR varies between three frequency ranges: f < 1k, between 1k and 4k, and f > 4k Hz. These findings show how the efficiency of the middle ear system for sound transmission changes during the presence of fluid in the cavity and variations of middle ear pressure.
Collapse
Affiliation(s)
- Rong Z Gan
- School of Aerospace and Mechanical Engineering and Bioengineering Center; University of Oklahoma, Norman, Oklahoma 73019, USA.
| | | | | |
Collapse
|
59
|
Morbiducci U, Scalise L, De Melis M, Grigioni M. Optical Vibrocardiography: A Novel Tool for the Optical Monitoring of Cardiac Activity. Ann Biomed Eng 2006; 35:45-58. [PMID: 17082980 DOI: 10.1007/s10439-006-9202-9] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2006] [Accepted: 09/11/2006] [Indexed: 01/09/2023]
Abstract
We present an optical non-contact method for heart beat monitoring, based on the measurement of chest wall movements induced by the pumping action of the heart, which is eligible as a surrogate of electrocardiogram (ECG) in assessing both cardiac rate and heart rate variability (HRV). The method is based on the optical recording of the movements of the chest wall by means of laser Doppler interferometry. To this aim, the ECG signal and the velocity of vibration of the chest wall, named optical vibrocardiography (VCG), were simultaneously recorded on 10 subjects. The time series built from the sequences of consecutive R waves (on ECG) and vibrocardiographic (VV) intervals were compared in terms of heart rate (HR). To evaluate the ability of VCG signals as quantitative marker of the autonomic activity, HRV descriptors were also calculated on both ECG and VCG time series. HR and HRV indices obtained from the proposed method agreed with the rate derived from ECG recordings (mean percent difference <3.1%). Our comparison concludes that optical VCG provides a reliable assessment of HR and HRV analysis, with no statistical differences in term of gender are present. Optical VCG appears promising as non-contact method to monitor the cardiac activity under specific conditions, e.g., in magnetic resonance environment, or to reduce exposure risks to workers subjected to hazardous conditions. The technique may be used also to monitor subjects, e.g., severely burned, for which contact with the skin needs to be minimized.
Collapse
Affiliation(s)
- Umberto Morbiducci
- Department of Mechanics, Università Politecnica delle Marche, Via Brecce Bianche, 60100 Ancona, Italy
| | | | | | | |
Collapse
|
60
|
Watters KF, Rosowski JJ, Sauter T, Lee DJ. Superior Semicircular Canal Dehiscence Presenting as Postpartum Vertigo. Otol Neurotol 2006; 27:756-68. [PMID: 16936563 DOI: 10.1097/01.mao.0000227894.27291.9f] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To describe the clinical and diagnostic features of superior semicircular canal dehiscence (SSCD) in patients with postpartum vertigo. STUDY DESIGN Retrospective review, meta-analysis. SETTING Tertiary neurotologic and audiologic center. PATIENTS Two women who presented with a history of acute postpartum vertigo and SSCD confirmed on high-resolution computed tomography (CT) were included. Our meta-analysis of the surgical SSCD literature comprised a total of 43 patients. INTERVENTION Patients with postpartum vertigo and SSCD underwent a complete medical evaluation, audiometric testing, CT imaging, magnetic resonance imaging studies, vestibular evoked myogenic potential testing, and laser Doppler vibrometer testing. Case 2 was managed with a middle fossa craniotomy and SSCD repair. RESULTS The first patient presented with normal hearing and aural fullness, autophony, and sound sensitivity of the left ear. A 1-mm left-sided SSCD was seen on CT imaging. She is being managed conservatively. The second patient had left-sided conductive hearing loss with sound and pressure sensitivity. The contralateral ear was congenitally deaf. CT imaging revealed a 4-mm left-sided SSCD. Because of her disabling symptoms, the patient underwent a middle fossa craniotomy and superior canal plugging. Her vestibular symptoms resolved with improvement in hearing. Vestibular evoked myogenic potential and laser Doppler vibrometer testing in both cases were consistent with SSCD. CONCLUSION This is the first description of patients with SSCD presenting after childbirth and should be included in the differential diagnosis of acute postpartum vertigo or disequilibrium. SSCD plugging can provide a stable repair with resolution of symptoms, reversal of diagnostic indicators, and hearing improvement.
Collapse
Affiliation(s)
- Karen F Watters
- Eaton-Peabody Laboratory, Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, Boston, MA, USA
| | | | | | | |
Collapse
|
61
|
Nakajima HH, Ravicz ME, Merchant SN, Peake WT, Rosowski JJ. Experimental ossicular fixations and the middle ear’s response to sound: Evidence for a flexible ossicular chain. Hear Res 2005; 204:60-77. [PMID: 15925192 DOI: 10.1016/j.heares.2005.01.002] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2004] [Accepted: 01/04/2005] [Indexed: 11/22/2022]
Abstract
A human temporal-bone preparation was used to determine the effects of various degrees of artificial ossicular fixation on the sound-induced velocity at the input-side (the umbo of the malleus) and the output-side (the stapes) of the ossicular chain. Construction of various degrees of attachment between an ossicle and the surrounding temporal bone provided a range of reduction in ossicular mobility or "fixations". The results demonstrate different effects of the fixations on the umbo and stapes velocity: fixations of the stapes or incus produce larger reductions in sound-induced stapes velocity (as much as 40-50 dB with extensive stapes fixation), than reductions in umbo velocity (typically less than 10 dB). Fixations of the malleus produce similar-sized changes in both umbo and stapes velocity. These differential effects are consistent with significant flexibility in the ossicular joints (the incudo-malleolar joint and the incudo-stapedial joint) that permits relative motion between the coupled ossicles. The existence of flexibility in the ossicular joints indicates that joints in the ossicular chain can effect a loss of sound-induced mechanical energy between the umbo and the stapes, with a concomitant reduction in the sound-induced motion of the stapes. The introduction of such losses in sound transmission by the joints raises questions concerning the utility of three ossicles in the mammalian ear. The consequences of ossicular flexibility to ossicular-chain reconstruction is discussed. Also, as examined in a more clinically directed paper [Laryngoscope 115 (2005) 147], the different effects of the various ossicular fixations on the motion of the umbo and malleus may be useful in the diagnosis of the site of fixations in humans with conductive hearing losses caused by such pathologies.
Collapse
Affiliation(s)
- Hideko Heidi Nakajima
- Department of Otology and Laryngology, Harvard Medical School, Boston, MA 02115, USA
| | | | | | | | | |
Collapse
|
62
|
Nakajima HH, Ravicz ME, Rosowski JJ, Peake WT, Merchant SN. Experimental and Clinical Studies of Malleus Fixation. Laryngoscope 2005; 115:147-54. [PMID: 15630384 DOI: 10.1097/01.mlg.0000150692.23506.b7] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES/HYPOTHESIS Preoperative clinical diagnosis of malleus fixation can be difficult. "Fixation" of the malleus can be caused by various disorders or diseases: fibrous tissue, bony spurs, and neo-osteogenesis around the malleus head or stiffening of the anterior malleal ligament. The conductive hearing loss produced by these disorders or diseases has not been well characterized. The study goals were 1) to determine the effects of various types of malleus fixation using a cadaveric temporal bone preparation and 2) to assess the clinical utility of umbo velocity measurements in preoperative differential diagnosis of malleus fixation and stapes fixation. METHODS Umbo and stapes velocity were measured in 18 fresh cadaveric human temporal bones with laser vibrometry before and after controlled application of adhesives to the malleus, stapes, or both ossicles. RESULTS Each simulated pathological condition produced a specific degree of loss in stapes velocity: stiffening of anterior malleal ligament, 0 to 8 dB; fibrous tissue around malleus head, less than 10 dB; bony bar to malleus head, 10 to 30 dB; and extensive neo-osteogenesis around malleus head, greater than 35 dB. Simulated malleus fixations generally produced similar reductions in both umbo and stapes velocity. Stapes fixation reduced stapes velocity with little change in umbo velocity. Because the change in stapes velocity would be similar to conductive hearing loss, experimental results were directly compared with clinical measurements of umbo velocity in surgically confirmed cases of malleus or stapes fixation. The effects of malleus and stapes fixations between the clinical and experimental data were similar. CONCLUSION The study showed that measurements of umbo velocity and air-bone gap can enable one to diagnose malleus fixation and specifies how to differentiate malleus from stapes fixation.
Collapse
Affiliation(s)
- Hideko Heidi Nakajima
- Department of Otology and Laryngology, Harvard Medical School, and the Eaton-Peabody Laboratory, Massachusetts Eye and Ear Infirmary, Boston, MA, USA
| | | | | | | | | |
Collapse
|
63
|
Whittemore KR, Merchant SN, Poon BB, Rosowski JJ. A normative study of tympanic membrane motion in humans using a laser Doppler vibrometer (LDV). Hear Res 2004; 187:85-104. [PMID: 14698090 DOI: 10.1016/s0378-5955(03)00332-0] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Laser Doppler vibrometry was used to measure the sound-induced tympanic membrane (TM) velocity, assessed near the umbo, in 56 normal hearing human subjects at nine sound frequencies. A second series of measurements was made in 47 subjects with sensorineural hearing loss (SNHL). Each set of measurements has features in common with previously published results. The measured velocity magnitude (normalized by the stimulus sound pressure) at any one frequency ranged among subjects by factors of 3-0.3 (+/-10 dB) from the mean and the phase angle of the normalized velocity ranged from +/-15 degrees around the mean at low frequencies to more than +/-200 degrees around the mean at 6 kHz. Measurements repeated after intervals of minutes to months were generally within 40% in magnitude (+/-3 dB) and 20 degrees in phase. Sources of variability included the effect of small differences in the location of the measurement on the TM and small static middle-ear pressures. No effects of stimulus level, ear sidedness (right or left), gender, age or the presence or absence of SNHL were found. These results provide a baseline normal response for studies of TM velocity with conductive hearing losses of different etiologies.
Collapse
Affiliation(s)
- Kenneth R Whittemore
- Department of Otology and Laryngology, Harvard Medical School, Boston, MA 02114, USA
| | | | | | | |
Collapse
|
64
|
Mikulec AA, McKenna MJ, Ramsey MJ, Rosowski JJ, Herrmann BS, Rauch SD, Curtin HD, Merchant SN. Superior semicircular canal dehiscence presenting as conductive hearing loss without vertigo. Otol Neurotol 2004; 25:121-9. [PMID: 15021770 DOI: 10.1097/00129492-200403000-00007] [Citation(s) in RCA: 195] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
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.
Collapse
Affiliation(s)
- Anthony A Mikulec
- Department of Otology and Laryngology, Harvard Medical School, and the Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts 02114, USA
| | | | | | | | | | | | | | | |
Collapse
|
65
|
Kakehata S, Futai K, Kuroda R, Shinkawa H. Office-Based Endoscopic Procedure for Diagnosis in Conductive Hearing Loss Cases Using OtoScan Laser-Assisted Myringotomy. Laryngoscope 2004; 114:1285-9. [PMID: 15235362 DOI: 10.1097/00005537-200407000-00027] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVES/HYPOTHESIS In conductive hearing loss (HL), even though preoperative examinations including audiometry, tympanometry, and computed tomography (CT) scan are applied, exploratory tympanotomy is necessary to make an exact diagnosis of ossicular interruption and stapes fixation. Precise preoperative diagnosis would be useful for patient counseling, surgical indications, and planning. The advantages of office-based OtoScan laser-assisted myringotomy (LAM), which makes a circular and non-hemorrhagic perforation, prompted us to investigate other uses of LAM in addition to ventilation and drainage of the tympanic cavity. To make presurgical diagnosis in conductive HL, endoscopes with an outer diameter of 1.7 or 1.9 mm were used to inspect the middle ear pathology through perforations with a diameter of 2 mm made by LAM. METHODS In the outpatient clinic, a circular perforation with a diameter of 2 mm was made in the tympanic membrane with LAM. An endoscopic view of the ossicular chain through a 70degrees angled tip endoscope held immediately to the outer side of the perforation was obtained to diagnose conduction disturbance loci in conductive HL cases. RESULTS Ossicular chain abnormalities were easily and safely detected by clean endoscopic views obtained through a nonhemorrhagic circular perforation. When necessary, insertion of the tip of the endoscope into the tympanic cavity provided additional views of epitympanum. CONCLUSION We suggest that transtympanic endoscopy through the perforation made by LAM is an effective and safe office-based procedure for diagnosis in conductive HL cases and could be an alternative procedure to replace exploratory tympanotomy.
Collapse
Affiliation(s)
- Seiji Kakehata
- Department of Otorhinolaryngology, Hirosaki University School of Medicine, Hirosaki, Japan.
| | | | | | | |
Collapse
|
66
|
Jia X, Burdick JA, Kobler J, Clifton RJ, Rosowski JJ, Zeitels SM, Langer R. Synthesis and Characterization of in Situ Cross-Linkable Hyaluronic Acid-Based Hydrogels with Potential Application for Vocal Fold Regeneration. Macromolecules 2004. [DOI: 10.1021/ma035970w] [Citation(s) in RCA: 159] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
67
|
Rosowski JJ, Songer JE, Nakajima HH, Brinsko KM, Merchant SN. Clinical, Experimental, and Theoretical Investigations of the Effect of Superior Semicircular Canal Dehiscence on Hearing Mechanisms. Otol Neurotol 2004; 25:323-32. [PMID: 15129113 DOI: 10.1097/00129492-200405000-00021] [Citation(s) in RCA: 182] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
HYPOTHESIS A superior semicircular canal dehiscence affects hearing by introducing a third window into the inner ear that 1) lowers cochlear input impedance, 2) shunts air-conducted sound away from the cochlea resulting in conductive hearing loss, and 3) improves bone-conduction thresholds by increasing the difference in impedance between the vestibule and the round window. BACKGROUND Superior semicircular canal dehiscence has been linked to a "conductive" hearing loss characterized by a decrease in the sensitivity to air-conducted sound and hypersensitivity to bone-conducted sound. METHODS Four investigations were performed: 1) laser-Doppler vibrometer measurements of sound-induced umbo velocity in patients with computed tomographic scan-confirmed superior semicircular canal dehiscence; 2) laser-Doppler vibrometry of sound-induced motions of the vestibular lymph (either perilymph or endolymph) exposed in a chinchilla model of superior semicircular canal dehiscence; 3) studies in chinchillas of the effect of superior semicircular canal dehiscence on the cochlea's sensitivity to bone-conducted sounds; and 4) anatomically based theoretical analyses of sound flow through the human cochlea and semicircular canals. RESULTS The low-frequency umbo velocity in superior semicircular canal dehiscence patients without previous middle ear surgery ranged from normal through high normal. This tendency toward hypermobility suggests a decrease in cochlear impedance. Measurements of sound-induced velocity of the lymph within a superior semicircular canal dehiscence in chinchillas demonstrated sound flow through the dehiscence. Measurements of the cochlear potential demonstrated a superior semicircular canal dehiscence-induced increase in response to bone-conducted sound in eight of nine chinchillas. An anatomically based model of the human ear predicts changes in auditory sensitivity similar to audiometric changes in superior semicircular canal dehiscence. CONCLUSION The results suggest that superior semicircular canal dehiscence can affect hearing function by introducing a third window into the inner ear.
Collapse
Affiliation(s)
- John J Rosowski
- Eaton-Peabody Laboratory, Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts 02114, USA.
| | | | | | | | | |
Collapse
|