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  • 1
    Online Resource
    Online Resource
    Modeling of the human middle ear using the finite-element method
    Acoustical Society of America (ASA) ; 2002
    In:  The Journal of the Acoustical Society of America Vol. 111, No. 3 ( 2002-03-01), p. 1306-1317
    Details
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 111, No. 3 ( 2002-03-01), p. 1306-1317
    Abstract: In this study, a three-dimensional finite-element model (FEM) of the human middle ear was established, including features of the middle ear which were not considered in the previous model, i.e., the ligaments, tendons, I–S joint, loading of the cochlea, external auditory meatus (EAM), middle-ear cavities, etc. The unknown mechanical properties of these parts and the boundary conditions were determined so that the impedance obtained from the FEM analysis resembled the measurement values. The validity of this model was confirmed by comparing the motion of the tympanic membrane and ossicles obtained by this model with the measurement data, and the effects of the newly considered features on the numerically obtained results were examined. By taking the ligaments and tendons into account and assuming that the cochlea acts as a damper, with this model it was possible to realistically reproduce complex ossicular chain movement. It was found that the middle-ear cavities did not affect the vibration mode of the tympanic membrane. Although the EAM enhanced the sound pressure applied to the tympanic membrane compared with that at the entrance of the EAM, the pressure distribution on the surface of the tympanic membrane was not affected by the EAM.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.1451073
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2002
    detail.hit.zdb_id: 1461063-2
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  • 2
    Online Resource
    Online Resource
    Dynamical behavior of middle ear: Theoretical study corresponding to measurement results obtained by a newly developed measuring apparatus
    Acoustical Society of America (ASA) ; 1990
    In:  The Journal of the Acoustical Society of America Vol. 87, No. 1 ( 1990-01-01), p. 237-245
    Details
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 87, No. 1 ( 1990-01-01), p. 237-245
    Abstract: An attempt is made to develop a new measuring apparatus, and the dynamical characteristics of the middle ear of normal subjects and patients are measured with this apparatus. Applying the impedance theory of the tube to the external auditory canal, the aditus and the tympanic and mastoid cavities, and applying the energy method to the eardrum and the ossicular chain, the equation of the middle ear, corresponding to the output of the apparatus and including the pressure difference effect upon the eardrum is obtained. The numerical results are compared with the measurement results, and the effects of each part of the middle ear upon its dynamical characteristics are clarified. The great dependence of the dynamical characteristics of the middle ear upon the external auditory canal pressure is mainly caused by the pressure-dependent ossicular chain angular stiffness. The clearly different measurement results of the ossicular chain disorder patients from those of the normal subjects are obtainable by this apparatus, and these characteristics can be explained theoretically.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.399290
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 1990
    detail.hit.zdb_id: 1461063-2
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  • 3
    Online Resource
    Online Resource
    Cochlin-Tomoprotein: A Novel Perilymph-Specific Protein and a Potential Marker for the Diagnosis of Perilymphatic Fistula
    S. Karger AG ; 2009
    In:  Audiology and Neurotology Vol. 14, No. 5 ( 2009), p. 338-344
    Details
    In: Audiology and Neurotology, S. Karger AG, Vol. 14, No. 5 ( 2009), p. 338-344
    Abstract: 〈 i 〉 Background: 〈 /i 〉 Perilymphatic fistula (PLF) is an abnormal connection between the inner and middle ear. A procedure for obtaining definite proof of a PLF remains elusive, and methods of diagnosis remain controversial. To date, there is no clinically relevant biochemical marker for perilymph leakage. Using proteomic analysis of inner ear proteins, we have previously found unique properties of cochlin, encoded by the 〈 i 〉 COCH 〈 /i 〉 gene. We detected 3 cochlin isoforms (p63s, p44s and p40s) in the inner ear tissue and a short 16-kDa isoform of cochlin-tomoprotein (CTP) in the perilymph. Since cochlin was found to be highly specific to the inner ear, we speculated that CTP might also be specific to the perilymph. The aim of this study was to determine whether CTP, a novel perilymph-specific protein, could be used as a marker for the diagnosis of PLF. 〈 i 〉 Methods: 〈 /i 〉 By Western blotting, we investigated the specificity of CTP expression in a range of body fluids that included perilymph, serum, saliva and cerebrospinal fluid. To elucidate the detection limit of CTP, serially diluted recombinant human (rh)CTP as well as human perilymph was tested. 〈 i 〉 Results: 〈 /i 〉 CTP was selectively expressed in all 20 perilymph samples tested, but not in 77 samples of the other body fluids. The detection limit of rhCTP was 0.27 ng or 0.022 μl of perilymph per well on Western blot analysis. 〈 i 〉 Conclusion: 〈 /i 〉 The results strongly suggest that CTP can be a specific marker of perilymph leakage. Moreover, CTP has the potential to be a biochemical marker that allows a definitive diagnosis of the etiology of PLF-related hearing loss and vestibular disorders.
    Type of Medium: Online Resource
    ISSN: 1420-3030 , 1421-9700
    URL: Article
    DOI: 10.1159/000212113
    Language: English
    Publisher: S. Karger AG
    Publication Date: 2009
    detail.hit.zdb_id: 1481979-X
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  • 4
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    Online Resource
    Randomized trial of granulocyte colony-stimulating factor for spinal cord injury
    Oxford University Press (OUP) ; 2021
    In:  Brain Vol. 144, No. 3 ( 2021-04-12), p. 789-799
    Details
    In: Brain, Oxford University Press (OUP), Vol. 144, No. 3 ( 2021-04-12), p. 789-799
    Abstract: Attenuation of the secondary injury of spinal cord injury (SCI) can suppress the spread of spinal cord tissue damage, possibly resulting in spinal cord sparing that can improve functional prognoses. Granulocyte colony-stimulating factor (G-CSF) is a haematological cytokine commonly used to treat neutropenia. Previous reports have shown that G-CSF promotes functional recovery in rodent models of SCI. Based on preclinical results, we conducted early phase clinical trials, showing safety/feasibility and suggestive efficacy. These lines of evidence demonstrate that G-CSF might have therapeutic benefits for acute SCI in humans. To confirm this efficacy and to obtain strong evidence for pharmaceutical approval of G-CSF therapy for SCI, we conducted a phase 3 clinical trial designed as a prospective, randomized, double-blinded and placebo-controlled comparative trial. The current trial included cervical SCI [severity of American Spinal Injury Association (ASIA) Impairment Scale (AIS) B or C] within 48 h after injury. Patients are randomly assigned to G-CSF and placebo groups. The G-CSF group was administered 400 μg/m2/day × 5 days of G-CSF in normal saline via intravenous infusion for five consecutive days. The placebo group was similarly administered a placebo. Allocation was concealed between blinded evaluators of efficacy/safety and those for laboratory data, as G-CSF markedly increases white blood cell counts that can reveal patient treatment. Efficacy and safety were evaluated by blinded observer. Our primary end point was changes in ASIA motor scores from baseline to 3 months after drug administration. Each group includes 44 patients (88 total patients). Our protocol was approved by the Pharmaceuticals and Medical Device Agency in Japan and this trial is funded by the Center for Clinical Trials, Japan Medical Association. There was no significant difference in the primary end point between the G-CSF and the placebo control groups. In contrast, one of the secondary end points showed that the ASIA motor score 6 months (P = 0.062) and 1 year (P = 0.073) after drug administration tend to be higher in the G-CSF group compared with the placebo control group. The present trial failed to show a significant effect of G-CSF in primary end point.
    Type of Medium: Online Resource
    ISSN: 0006-8950 , 1460-2156
    URL: Article
    DOI: 10.1093/brain/awaa466
    RVK:
    XA 10000
    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 2021
    detail.hit.zdb_id: 1474117-9
    SSG: 12
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  • 5
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    Online Resource
    Dynamic behavior of the human middle ear: A finite-element method (FEM) analysis
    Acoustical Society of America (ASA) ; 1996
    In:  The Journal of the Acoustical Society of America Vol. 100, No. 4_Supplement ( 1996-10-01), p. 2785-2785
    Details
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 100, No. 4_Supplement ( 1996-10-01), p. 2785-2785
    Abstract: A few investigations of finite-element method (FEM) application to the analysis of the middle ear have already been reported [Funnell et al., J. Acoust. Soc. Am. 81, 1851–1859 (1987); K. R. Williams and T. H. J. Lesser, Br. J. Audiol. 24, 319–327 (1990)]. However, in the models of these studies, ossicles and middle ear cavities were neglected, and their effects on the dynamic behavior of the middle ear have not been analyzed. In this study, first, applying the authors’ own FEM program, a three-dimensional FEM model of a human auditory periphery was established. Then, vibration modes and transfer functions of the middle ear were obtained. The following conclusions can be drawn. (1) The vibration mode of the tympanic membrane and ossicles changes considerably due to the elastic ligament support of the ossicles. (2) This change enables the transfer function of the middle ear to keep flat. (3) The effect of the cavities on the dynamic behavior of the middle ear is large; the amplitude of the tympanic membrane vibration after opening the cavities is nearly two times larger than that before opening them. [Work supported by Research Fellowships of the Japan Society for the Promotion of Science for Young Scientists.]
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.416463
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 1996
    detail.hit.zdb_id: 1461063-2
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  • 6
    Online Resource
    Online Resource
    A digital hearing aid that compensates loudness for impaired listeners and its performance
    Acoustical Society of America (ASA) ; 1990
    In:  The Journal of the Acoustical Society of America Vol. 88, No. S1 ( 1990-11-01), p. S169-S169
    Details
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 88, No. S1 ( 1990-11-01), p. S169-S169
    Abstract: A method of designing a digital hearing aid for speech signal suitable for sensorineural hearing loss with a narrow audible range is proposed. First, the input signal is divided into short time blocks (8 ms) and its spectrum is analyzed using short-time FFT. Then the frequency-gain characteristic of the digital filter for the block is determined using loudness compensation functions that describe the relation between the loudness of normal listeners and that of impaired listeners, so that the input signal within the block is projected on to the dynamic range of the subject. This algorithm is realized using a digital signal processor (DSP). The results of monosyllabic intelligibility tests to evaluate the performance of the system for six sensorineural impaired listeners are also shown. [Work supported by Grant-in-Aid for Scientific Research from the Ministry of Education and the Ministry of Public Welfare.]
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.2028744
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 1990
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  • 7
    Online Resource
    Online Resource
    Analysis of dynamic behavior of human middle ear using a finite-element method
    Acoustical Society of America (ASA) ; 1992
    In:  The Journal of the Acoustical Society of America Vol. 92, No. 6 ( 1992-12-01), p. 3157-3168
    Details
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 92, No. 6 ( 1992-12-01), p. 3157-3168
    Abstract: Applying the general-purpose finite-element package program (ISAP), a three-dimensional finite-element method (FEM) model of a human right middle ear, which included ossicles, was made and the mechanical properties and boundary conditions of the middle ear were determined by a comparison between the numerical results obtained from the FEM analysis and the measurement results of the fresh cadavers, normal subjects and patients, which were obtained by our developed sweep frequency middle ear analyzer (MEA). The ‘‘Elastic’’ boundary condition consisting of linear and torsional springs at the eardrum attachments to the annular ligament was more appropriate for the actual condition than ‘‘fully clamped’’ one. Rotational axis of the ossicular chain was assumed to be a fixed straight line from the anterior process of the malleus to the short process of the incus, and a load of the ossicular chain and cochlea was simplified to be expressed by the stiffness of the cochlea. Vibration patterns of the eardrum and ossicles at the first resonance frequency, obtained under these assumptions, were in agreement with the experimental results obtained by means of time-averaged holography and by using a video measuring system, except for the relatively large displacements at the tympanic ring.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.404211
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 1992
    detail.hit.zdb_id: 1461063-2
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  • 8
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    Online Resource
    Effect of two-band dichotic listening for hearing impaired listeners
    Acoustical Society of America (ASA) ; 2005
    In:  The Journal of the Acoustical Society of America Vol. 117, No. 4_Supplement ( 2005-04-01), p. 2608-2608
    Details
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 117, No. 4_Supplement ( 2005-04-01), p. 2608-2608
    Abstract: The increase of the upward spread of masking is a phenomenon that is typically observed among sensorineural hearing-impaired listeners. To resolve this problem, dichotic listening, by which an input speech spectrum is split into two complementary parts and is presented dichotically, seems effective to reduce masking between contiguous frequency bands. This study examines effects of simple two-band dichotic listening with a cut-off frequency around and between the typical first and second formant frequencies of the preceding vowel. We measured speech intelligibilities in both quiet and noisy environments (S/N 4 and 0 dB). Three types of vowel-consonant-vowel nonsense monosyllables, of which preceding vowels were /a/, /i/, and /u/, were used as speech stimuli. Results showed that this dichotic processing was effective, especially in relatively high S/N conditions. Moreover, the best dividing frequency was dependent on the preceding vowel. When /a/-consonant-vowel was used, the best dividing frequency was 1.0 kHz (around F1 of Japanese vowel /a/), whereas the best dividing frequency was 0.8 kHz (between F1 and F2 of Japanese vowel /u/) when the /u/-consonant-vowel was used.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.4777893
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2005
    detail.hit.zdb_id: 1461063-2
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  • 9
    Online Resource
    Online Resource
    Vibration measurement of the tympanic membrane of guinea pig temporal bones using time-averaged speckle pattern interferometry
    Acoustical Society of America (ASA) ; 2002
    In:  The Journal of the Acoustical Society of America Vol. 111, No. 5 ( 2002-05-01), p. 2189-2199
    Details
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 111, No. 5 ( 2002-05-01), p. 2189-2199
    Abstract: “Time-averaged holography” and “holographic interferometry” enable recording of the complete vibration pattern of a surface within several seconds. The results appear in the form of fringes. Vibration amplitudes smaller than 100 nm are not readily measurable by these techniques, because such small amplitudes produce variations in gray level, but not fringes. In practice, to obtain clear fringes in these measurements, stimulus sound pressures higher than 100 dB SPL must be used. The phase of motion is also not obtainable from such fringe techniques. In this study, a sinusoidal phase modulation technique is described, which allows detection of both small amplitudes of motion and their phase from time-averaged speckle pattern interferometry. In this technique, the laser injection current is modulated and digital image processing is used to analyze the measured patterns. When the sound-pressure level of stimuli is between 70 and 85 dB SPL, this system is applied to measure the vibratory response of the tympanic membrane (TM) of guinea pig temporal bones at frequencies up to 4 kHz where complicated vibration modes are observed. The effect of the bulla on TM displacements is also quantified. Results indicate that this system is capable of measuring the nanometer displacements of the TM, produced by stimuli of 70 dB SPL.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.1467671
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2002
    detail.hit.zdb_id: 1461063-2
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  • 10
    Online Resource
    Online Resource
    Effects of dichotic listening for hearing impaired people
    Acoustical Society of America (ASA) ; 2006
    In:  The Journal of the Acoustical Society of America Vol. 120, No. 5_Supplement ( 2006-11-01), p. 3348-3349
    Details
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 120, No. 5_Supplement ( 2006-11-01), p. 3348-3349
    Abstract: Methods applying the dichotic listening algorithm have been proposed and examined for application in hearing aids. Murase et al. (2005) proposed an algorithm in which dichotic listening was simply implemented by a set of complementary high-pass and low-pass filters. One filter is for either the right or left channel; the other filter is used for the other channel. This study examined two unsolved problems with this algorithm. One is the reason why this algorithm is effective. The other is probable degradation of sound localization that occurs because interaural level differences and interaural time differences is only slightly available with this signal processing. This problem is considerable when the sounds come from frontal incidence. Regarding the first problem, intelligibility tests were performed using the low-frequency-boosted sounds. The intelligibility scores under the dichotic listening conditions should be higher than those under the diotic listening conditions if the effectiveness of this algorithm is attributable to the reduction of upward spread of masking. Results suggest that this dichotic listening reduced the upward spread of masking. Regarding degradation of performance of sound localization, sound localization test results suggest that time-intensity trading might recover degradation with dichotic listening algorithm.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.4781397
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2006
    detail.hit.zdb_id: 1461063-2
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