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1.
目的比较双侧人工耳蜗植入(CI)儿童安静和噪声条件下双耳与单耳开放式双音节词识别率的差异,以及噪声条件下易词与难词识别率差异,结合个案基本情况和CAP和SIR问卷评估结果,分析影响双音节词识别率的个性化因素。方法利用普通话儿童相邻性词表测试工具对9例双侧CI儿童进行安静和噪声条件下的双音节词测试,通过配对t检验,比较双耳与单耳双音节词识别率及易词与难词识别率差异。结果在安静和噪声条件下,双耳与单耳CI双音节识别率差异显著(P<0.05);在噪声条件下,双耳与单耳易词和难词识别率差异极显著(P<0.01);双音节词识别率受个体CI年龄、言语可懂度、内耳畸形类型等因素影响。结论在安静和噪声条件下,双耳CI可提高双音节识别率;在噪声条件下,双耳CI优势更加突出;儿童言语识别率受易词和难词以及儿童个性化等因素影响。  相似文献   
2.
The cochlea of our auditory system is an intricate structure deeply embedded in the temporal bone. Compared with other sensory organs such as the eye, the cochlea has remained poorly accessible for investigation, for example, by imaging. This limitation also concerns the further development of technology for restoring hearing in the case of cochlear dysfunction, which requires quantitative information on spatial dimensions and the sensorineural status of the cochlea. Here, we employed X-ray phase-contrast tomography and light-sheet fluorescence microscopy and their combination for multiscale and multimodal imaging of cochlear morphology in species that serve as established animal models for auditory research. We provide a systematic reference for morphological parameters relevant for cochlear implant development for rodent and nonhuman primate models. We simulate the spread of light from the emitters of the optical implants within the reconstructed nonhuman primate cochlea, which indicates a spatially narrow optogenetic excitation of spiral ganglion neurons.

In the case of profound sensorineural hearing impairment, cochlear implants (CIs) partially restore hearing by providing auditory information to the brain via electrical stimulation of the spiral ganglion neurons (SGNs). CIs enable speech understanding in the majority of the ∼700,000 users worldwide. However, current clinical CIs are limited by their wide current spread (1) resulting in poor coding of spectral information (2). Recently, cochlear optogenetics was proposed for stimulating the auditory nerve by light (310). As light can be better confined in space, the spread of excitation in the cochlea is lower (3, 911) and, hence, future optical CIs (oCIs) promise improved speech comprehension—especially in noisy background—as well as greater music appreciation.For the technical development of oCIs toward a future medical device, major efforts are currently being undertaken to devise multichannel optical stimulators for the cochlea (10, 1217). As is the case for the electrodes of current CIs, future oCIs will place multiple stimulation channels, here microscale emitters, along the tonotopic axis of the cochlea. Further development of the oCIs requires precise estimates of parameters such as scala tympani size, optimal probe stiffness, and bending radius. Moreover, cochlear optogenetics employs gene transfer to the SGNs for which adeno-associated viruses (AAVs) seem promising candidate vectors (35, 8). AAV delivery has used injection of virus suspension via the round window (4, 8) or directly into Rosenthal’s canal (5, 9, 10). Therefore, the volumes of Rosenthal’s canal and the scalae tympani, vestibuli and media needed to be evaluated in order to estimate the required virus load for injection. Finally, the sensorineural status of the cochlea is highly relevant for future gene therapy and CI stimulation, and hence, quantitative imaging of sensory cells and neurons is an important objective.Here, we employed multiscale X-ray phase-contrast tomography (XPCT) and light-sheet fluorescence microscopy (LSFM) and provide an analysis of cochlear morphology for mice, rats, gerbils, guinea pigs, and marmosets. Each of these animal models offers unique advantages for auditory research. The mouse is readily available for genetic manipulation (e.g., ref. 18). Channelrhodopsin-expressing transgenic lines are available also for rats (19, 20) that offer a larger cochlea and can carry heavier implants than mice (2124). Similarly, gerbils and guinea pigs are established rodent models for auditory research with larger-sized cochleae. Moreover, gerbils, which have low-frequency hearing more similar to humans, have already been employed for cochlear optogenetics (5, 9, 10, 24). Finally, we analyzed the cochlea of the common marmoset, as an established nonhuman primate model for auditory research (e.g., refs. 25, 26). Marmosets possess a rich vocalization repertoire and share a pitch perception mechanism with humans (27). Therefore, we compared cochlear insertion of newly designed oCIs with electrical cochlear implants (eCI) and modeled the optical spread of excitation in the marmoset cochlea.  相似文献   
3.
MR三维颅脑容积成像增强扫描诊断内听道区病变   总被引:1,自引:1,他引:0  
目的探讨MR三维颅脑容积成像(3D-BRAVO)增强扫描诊断内听道区病变的价值。方法对81例内听道区病变患者(116个病灶)行3D-BRAVO增强扫描及常规增强MR检查,对比两种方法诊断内听道区病变的敏感度。结果常规增强扫描发现阳性病灶86个,诊断敏感度71.55%(83/116),漏诊率28.45%(33/116);3D-BRAVO增强扫描检出全部116个阳性病灶,诊断敏感度100%(116/116);3D-BRAVO增强扫描诊断敏感度高于常规增强扫描(Z=-3.74,P<0.001)。结论3D-BRAVO增强扫描可敏感检出内听道区病变,为临床诊疗提供影像学证据。  相似文献   
4.
目前电子耳蜗主流的言语处理策略是基于滤波器组的言语处理算法,该算法通过分频带进行信号处理并把参数传递到对应的电极上。电子耳蜗滤波器组的频带划分不是等分的,而是按一定规律进行并且符合人耳听觉特性的,其中,Bark域的频带划分是重要的参考。本研究基于Bark域的电子耳蜗频带划分方法,探讨Bark域频带划分的特性并结合目前的电子耳蜗滤波器组的频带划分进行分析,进而探讨频带划分中的曲线拟合方法,为电子耳蜗滤波器组中的频带划分提供重要的方法和参数。  相似文献   
5.
Abstract

Objective

Satisfactory musical sound quality remains a challenge for many cochlear implant (CI) users. In particular, questionnaires completed by CI users suggest that reverberation due to room acoustics can negatively impact their music listening experience. The objective of this study was to more specifically characterize of the effect of reverberation on musical sound quality in CI users, normal hearing (NH) non-musicians, and NH musicians using a previously designed assessment method, called Cochlear Implant-MUltiple Stimulus with Hidden Reference and Anchor (CI-MUSHRA).

Methods

In this method, listeners were randomly presented with an anechoic musical segment and five-versions of this segment in which increasing amounts of reverberation were artificially added. Participants listened to the six reverberation versions and provided sound quality ratings between 0 (very poor) and 100 (excellent).

Results

Results demonstrated that on average CI users and NH non-musicians preferred the sound quality of anechoic versions to more reverberant versions. In comparison, NH musicians could be delineated into those who preferred the sound quality of anechoic pieces and those who preferred pieces with some reverberation.

Discussion/Conclusion

This is the first study, to our knowledge, to objectively compare the effects of reverberation on musical sound quality ratings in CI users. These results suggest that musical sound quality for CI users can be improved by non-reverberant listening conditions and musical stimuli in which reverberation is removed.  相似文献   
6.
Objective: To examine usage patterns of hearing aids and cochlear implants in children up to three years of age, how usage changes longitudinally, and factors associated with device usage. Design: Parent report and Parent’s Evaluation of Aural/oral Performance of Children (PEACH) data were obtained at six and twelve months after hearing-aid fitting or cochlear implant switch-on, and again at three years of age. The effect of device use on auditory functional performance was investigated using the PEACH questionnaire. Study sample: Four hundred and thirteen participants from the Longitudinal Outcomes of Children with Hearing Impairment (LOCHI) study were included for analysis. Results: For users of hearing aids, higher usage at three years was associated with higher maternal education, and more severe hearing loss. For users of cochlear implants, higher usage was associated with higher maternal education and the absence of additional disabilities. Higher PEACH scores were associated with higher usage scores. After allowing for the effects of demographic characteristics, device use was not a significant predictor of functional performance. Conclusions: Sixty-two percent of children achieved consistent use (> 75% of waking hours) within the first year of receiving a hearing aid or a cochlear implant, and 71% by three years of age.  相似文献   
7.
Conclusion: Polymer-coated electrodes can reduce surgically-induced trauma associated with the insertion of a cochlear implant (CI) electrode array. Objectives: To evaluate if insertion trauma in CI surgery can be reduced by using electrode arrays coated with 2-methacryloyloxyethyl phosphorylcholine (MPC) polymer. Methods: We analyzed characteristics of the Contour Advance® electrode arrays coated with MPC polymer. To assess surgical trauma during electrode insertion, polymer-coated or uncoated (n = 5 each) animal electrode arrays were implanted in guinea pig cochleae and operability and electrophysiological and histological changes were assessed. Results: Under light and scanning electron microscopy, polymer-coated electrodes did not appear different from uncoated electrodes, and no change was observed after mechanical stressing of the arrays. Electrode insertion was significantly easier when polymer-coated electrodes were used. Auditory brainstem response (ABR) thresholds did not differ between groups, but p1-n1 amplitudes of the coated group were larger compared with the uncoated group at 32 kHz at 28 days after surgery. The survival of outer hair cells and spiral ganglion cells was significantly greater in the polymer-coated group.  相似文献   
8.
Cochlear implant (CI) users usually exhibit marked across-electrode differences in detection thresholds with “focused” modes of stimulation, such as partial-tripolar (pTP) mode. This may reflect differences either in local neural survival or in the distance of the electrodes from the modiolus. To shed light on these two explanations, we compared stimulus-detection thresholds and gap-detection thresholds (GDTs) at comfortably loud levels for at least four electrodes in each of ten Advanced Bionics CI users, using 1031-pps pulse trains. The electrodes selected for each user had a wide range of stimulus-detection thresholds in pTP mode. We also measured across-electrode variations in both stimulus-detection and gap-detection tasks in monopolar (MP) mode. Both stimulus-detection and gap-detection thresholds correlated across modes. However, there was no significant correlation between stimulus-detection and gap-detection thresholds in either mode. Hence, gap-detection thresholds likely tap a source of across-electrode variation additional to, or different from, that revealed by stimulus-detection thresholds. Stimulus-detection thresholds were significantly lower for apical than for basal electrodes in both modes; this was only true for gap detection in pTP mode. Finally, although the across-electrode standard deviation in stimulus-detection thresholds was greater in pTP than in MP mode, the reliability of these differences—assessed by dividing the across-electrode standard deviation by the standard deviation across adaptive runs for each electrode—was similar for the two modes; this metric was also similar across modes for gap detection. Hence across-electrode differences can be revealed using clinically available MP stimulation, with a reliability comparable to that observed with focused stimulation.  相似文献   
9.
Otoacoustic emissions (OAEs) are faint sounds generated by healthy inner ears that provide a window into the study of auditory mechanics. All vertebrate classes exhibit OAEs to varying degrees, yet the biophysical origins are still not well understood. Here, we analyzed both spontaneous (SOAE) and stimulus-frequency (SFOAE) otoacoustic emissions from a bird (barn owl, Tyto alba) and a lizard (green anole, Anolis carolinensis). These species possess highly disparate macromorphologies of the inner ear relative to each other and to mammals, thereby allowing for novel insights into the biomechanical mechanisms underlying OAE generation. All ears exhibited robust OAE activity, and our chief observation was that SFOAE phase accumulation between adjacent SOAE peak frequencies clustered about an integral number of cycles. Being highly similar to published results from human ears, we argue that these data indicate a common underlying generator mechanism of OAEs across all vertebrates, despite the absence of morphological features thought essential to mammalian cochlear mechanics. We suggest that otoacoustic emissions originate from phase coherence in a system of coupled oscillators, which is consistent with the notion of “coherent reflection” but does not explicitly require a mammalian-type traveling wave. Furthermore, comparison between SFOAE delays and auditory nerve fiber responses for the barn owl strengthens the notion that most OAE delay can be attributed to tuning.Numerous fundamental biophysical questions regarding cochlear mechanics remain unanswered, such as the relative dominance between viscous and inertial fluid forces affecting the stimulation of hair cells and the longitudinal coupling between them (1, 2). These aspects, combined with relative experimental inaccessibility, have led to much uncertainty with regard to the micromechanics at work in the organ of Corti, and thereby precisely how auditory information is initially peripherally encoded (i.e., forward transduction). One area in which there is broad agreement, however, is the notion of an “active” ear: A nonlinear amplification mechanism(s) (i.e., reverse transduction) boosts detection of low-level sounds and compresses a wide range of sound intensities into a narrower range of vibration magnitude (3). One manifestation of this process is the existence of otoacoustic emissions (OAEs), sounds measurable noninvasively in the external ear canal using a sensitive microphone (4). Because only healthy ears tend to emit, OAEs have had a significant clinical impact (e.g., pediatric audiology). Emissions can arise spontaneously (SOAEs) or be evoked by an external stimulus. In fact, SOAEs are commonly pointed to as salient evidence for active amplification, especially given their connections to perception such as “rippling” in audiograms (threshold microstructure), indicative of localized changes in detection thresholds (5, 6). SOAEs are, however, idiosyncratic in nature: Not all mammalian species have them, whereas several nonmammalian classes such as lizards exhibit robust activity. Humans have a high incidence of SOAEs, although some (healthy) ears have them but others do not. So, although SOAEs are not required per se for sensitive hearing, they provide a powerful and noninvasive means to study the function of the inner ear.A common thread through vertebrate OAEs studies is that of an active oscillator, typically a stereovillar hair cell, acting as the essential transducer (3, 710). A comprehensive theory for SOAE generation across vertebrates is lacking, however, because knowledge of hair cell physiology has not yet been well connected to the collective behavior of the system as a whole. Vertebrate ears contain anywhere from 50 to 20,000 hair cells, all coupled together to varying degrees. Two different, and seemingly diametric, theoretical approaches explaining SOAEs have emerged. One model class considers the ear as a system of coupled nonlinear oscillators exhibiting a limit cycle (3, 1113). Typically, these models are “local” in that a given oscillator is only directly coupled to its nearest neighbors. The other class focuses predominantly on the mammalian cochlea (1419), where “global” coupling between elements arises from the hydromechanics that give rise to wave mechanics. One salient example is the standing wave model (16), where the peak of the traveling wave and stapes act as the two reflecting boundaries with a nonuniform gain medium in between, somewhat akin to a laser. That study predicted and verified interrelationships between spontaneous and evoked OAEs. Furthermore, acknowledging that nonmammalian ears exhibit different mechanics, Shera (16) proposed that the appearance of “standing waves” need not necessarily depend upon traveling waves along the basilar membrane (BM) but could arise via other mechanisms that create appropriate phase differences (e.g., delays due to tuning). Motivated by the uncertain role of BM traveling waves in nonmammals, our present goal was to exploit the large morphological differences that exist across vertebrate ears (20) to gain quantitative insight into SOAE generation mechanisms.Here we focus on two different nonmammalian species: a bird, the barn owl, and a lizard, the green anole. Both species exhibit robust OAE activity (2125). The barn owl (Tyto alba), is known for its remarkable ability to hunt by auditory cues alone (26). The peripheral auditory morphology, neurophysiology, and psychophysics of this species have been well characterized (2730). Owl auditory nerve fiber (ANF) responses show average frequency tuning but have remarkably high phase-locking capabilities extending out to 10 kHz (31). Furthermore, the tonotopic map along the basilar papilla (in contrast to the mammalian organ of Corti) is nonexponential, with representation of higher frequencies (5–10 kHz) greatly expanded. The role of BM waves is unknown in owls, although data from pigeons are suggestive of their existence in birds (32). The inner ear of lizards is profoundly different from that of both humans and barn owls. In anoles, the short auditory papilla (∼0.5 mm) contains ∼150 hair cells and has no overlying tectorial membrane over the SOAE-producing cells (33). Bundle orientations for hair cells in a given radial cross-section are arranged in a self-opposing fashion. Furthermore, there is ample evidence indicating a lack of a traveling wave on the BM (34, 35). In this study, we systematically explored interrelationships within individual ears between SOAEs and stimulus frequency emissions (SFOAEs), the simplest type of evoked emission via a single low-level stimulus tone (15). In short, we found that important OAE characteristics are shared between the two species and with published data from humans. This we interpret as revealing generic features of the underlying active processes.  相似文献   
10.
Traveling waves in the inner ear exhibit an amplitude peak that shifts with frequency. The peaking is commonly believed to rely on motile processes that amplify the wave by inserting energy. We recorded the vibrations at adjacent positions on the basilar membrane in sensitive gerbil cochleae and tested the putative power amplification in two ways. First, we determined the energy flux of the traveling wave at its peak and compared it to the acoustic power entering the ear, thereby obtaining the net cochlear power gain. For soft sounds, the energy flux at the peak was 1 ± 0.6 dB less than the middle ear input power. For more intense sounds, increasingly smaller fractions of the acoustic power actually reached the peak region. Thus, we found no net power amplification of soft sounds and a strong net attenuation of intense sounds. Second, we analyzed local wave propagation on the basilar membrane. We found that the waves slowed down abruptly when approaching their peak, causing an energy densification that quantitatively matched the amplitude peaking, similar to the growth of sea waves approaching the beach. Thus, we found no local power amplification of soft sounds and strong local attenuation of intense sounds. The most parsimonious interpretation of these findings is that cochlear sensitivity is not realized by amplifying acoustic energy, but by spatially focusing it, and that dynamic compression is realized by adjusting the amount of dissipation to sound intensity.  相似文献   
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