常见的听觉滤波器

听觉滤波器在理解听觉形成机制、听觉系统建模、语音压缩和语音识别等很多方面都有着很重要的应用.本文系统地综述了几种常见的听觉滤波器,包括它们的定义、幅频曲线,以及各自在模拟基底膜的非线性、频率选择特性及滤波特性上的优缺点.在此基础上,本文也对这些听觉滤波器进行了比较,阐述了它们之间的区别和联系.     

正常豚鼠cAP调谐曲线短纯音前掩蔽法与同时掩蔽法的对照研究

本文介绍用国产声刺器实现前掩蔽法测试ｃＡＰ调谐曲线的方法，并与同时掩蔽法测试的正常豚鼠１０耳ｃＡＰ调谐曲线的参数进行比较。探测音用２ｋＨｚ、４ｋＨｚ相位交替的滤波短声。掩蔽用上升、下降时间为１０ｍｓ，平台时程为５０ｍｓ的短纯音，纯音平台尾部比探测音中心点超前１５ｍｓ。实验表明，前掩蔽法ｃＡＰ－ＴＣ的Ｑ（１０ｄＢ）值比同时掩蔽法的Ｑ（１０ｄＢ）值大，前者特征频率所需掩蔽声级比后者小，两者有显著差异。     

基于噪声调制的电子耳蜗听觉仿真模型的建立

听觉仿真实验模拟耳聋患者植入电子耳蜗后的实际电听觉效果,能快速的检验电子耳蜗语音处理算法的有效性.听觉仿真模型的建立可以采用正弦调制和噪声调制两种方式,本文讨论了基于噪声调制的模型建立方法,并以SPEAK算法为例,建立了该算法的噪声调制听觉仿真模型,在此基础上设计了听觉仿真实验并对模型进行了验证.仿真实验的结果证明了该类模型的合理性与有效性,为初步评估电子耳蜗语音处理算法提供了一种新的方法.     

基于中耳与耳蜗集成有限元模型的耳声传递模拟

建立外耳道、中耳和简化耳蜗集成的有限元模型,包含中耳和耳蜗结构、耳道和中耳腔内的空气以及耳蜗内的液体.采用声-结构耦合动力学分析,计算声音由外耳道向内耳的传递过程,获得了鼓膜、镫骨足板的位移、中耳的声压增益、前庭阶的压力分布,同时也模拟了基底膜自蜗底至顶端的频率选择特性.计算结果与相关文献的实验结果具有较好的一致性,说明本模型对中耳传声功能模拟的准确性.结果表明,改进的耳蜗模型可为耳蜗运动功能模拟的探索提供更充分和合理的信息.     

耳蜗基底膜振动模型的建立与应用

人的耳蜗是一个非凡的感觉器件。它可以分辨出强度差别极其微小和频率非常相近的不同的声音。本文首先通过介绍耳蜗基底膜与听觉结构的生理和解剖特性,然后从数学和物理学的角度分析耳蜗基底膜的结构特性,从而建立了耳蜗基底膜的振动模型。最后应用该模型分析,结果发现本文所建立的耳蜗基底膜振动模型得出的结果与临床解剖和生理实验的结果十分吻合。     

413例眩晕病人脑干听觉诱发电位和耳蜗电图的分析

对413例眩晕病人作脑干听觉诱发电位(BAEP)检测。其中98例伴耳蜗症状的病人进一步做耳蜗电图(ECochG)检测。异常检出数分别为BAEP 83例,ECochG 71例。讨论听觉诱发电位在眩晕病蜗性病变和蜗后性病变的定位诊断及临床意义。     

基于Bark域的电子耳蜗频带划分分析和拟合研究

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。     

基于频率调谐的非侵入性神经调制手段在精神疾病中的应用

大脑中不同节律的神经振荡与认知、注意、记忆、情绪等功能,及多种神经精神疾病的临床症状密切相关.通过外部施加节律性刺激可以调制神经活动.大脑内特定频率的神经振荡被外界节律性刺激调制而产生相位锁定的现象称为神经振荡-外界节律同步化.这种同步化现象为非侵入性神经调制提供了新思路.目前,基于频率调谐的非侵入性神经调制方法已被应用于精神疾病干预,通过调控神经活动可缓解精神疾病患者的症状.对基于频率调谐的非侵入性神经调制方法及其临床应用进行总结将有助于促进其技术发展及进一步的应用推广.本文首先介绍了神经振荡-外界节律同步化的潜在机制,然后总结了当前基于频率调谐的非侵入性神经调制方法,接着梳理了其在精神疾病领域的应用,最后对其未来的发展方向进行了展望.基于频率调谐的非侵入性神经调制手段不仅有助于理解神经振荡与精神疾病的关系,发现精神疾病的神经标志物,而且为精神疾病的非侵入性神经调控提供了新的方法和思路.     

彩色超声成像中回归型滤波器的设计与实现

壁滤波是彩色超声血流成像系统中的一项关键技术。我们介绍了超声多普勒血流信号的产生原理及壁信号的抑制方法;其次比较了几种壁滤波器的优缺点,并且得到了回归型滤波器在低速血流信号中的有效应用;然后利用回归型滤波器对血流信号进行处理。结果表明,这是一种简单有效的壁滤波器设计实现方法,性能优于传统的壁滤波器。     

发生检验结果错误的种类与频率

为探讨发生检验结果错误的种类与频率,以寻找最主要的误差来源,从而制订相应的对策。我们选择急症科、内科、儿科为被调查科室,其调查14568份检验结果,其错误分布频率为:分析前占70.2%,分析中占14.3%。分析后占15.5%。     

Auditory deprivation and health in the elderly

Age-related hearing loss is a common disorder with important consequences for quality of life. We performed a systematic review of the evidence investigating the effect of age-related hearing loss on cognition and quality of life in the elderly, and evaluated the effect of interventions for hearing loss.There is a large body of evidence associating hearing loss with detriment to physical and mental health, cognition, independence, social interaction and quality of life in the elderly. Hearing rehabilitation programmes, hearing aids and cochlear implants show beneficial effects in restoring communicative ability in this group and subsequently improve quality of life. Furthermore, much of the benefit seen is comparable to that in younger adults.However, both identifying those at need of such interventions and implementing them effectively are sub-optimal. Treatment approaches that better address the difficulties within this group need to be developed and the role significant others have to play in hearing rehabilitation should be explored.     

影像系统MTF算法实现及分析

调制传输函数可对线性影像系统的频率传输特性进行描述.利用调制传输函数计算空间分辨率与线对卡方法相比,虽然测量方法复杂,但是利用调制传输函数对系统性能进行评价会更客观、更全面.利用编写的调制传输函数计算程序对CT和MRI的频率传输特性进行计算,并与线对卡检测结果进行了比较和讨论.证明利用调制传输函数分析系统的频率特性更全面及MTF程序的有效性.     

The effect of cochlear nerve lesion on the release of glutamate,aspartate, and GABA from cat cochlear nucleus,in vitro

Summary Pool studies of glutamate and aspartate have suggested a transmitter role for these amino acids in cochlear nerve endings. As further evidence. the K⁺-evoked release of glutamate, aspartate and GABA was measured in cat cochlear nucleus slices in vitro and compared to the release following a cochlear nerve lesion. Using [³H]glutamine as precursor, the K⁺-evoked release of glutamate and -aminobutyric acid (GABA) was respectively 4.1 and 7.2 times the spontaneous release. Using [¹⁴C]glutamate as a marker, the K⁺-evoked release of glutamate and GABA was respectively 7.1 and 2.8 times the basal release. All K⁺-evoked releases were Ca⁺⁺-dependent. Nine days after unilateral lesion of the cochlear nerve in the cat, the glutamate release decreased by about 75% on the lesioned side compared to the intact one, whereas the GABA release was not decreased. The labelled tissue glutamate, either synthesized from [³H]glutamine or labelled with [¹⁴C]glutamate, was also markedly decreased on the lesioned side. In comparison, the evoked release of aspartate, newly synthesized from [¹⁴C]glutamate, remained low and was only decreased by about 45% after cochlear nerve lesions. Comparing cat with rat cochlear nucleus, the glutamate release was similar in both animals, whereas the GABA release was much higher in the rat.It is concluded that glutamate and to a lesser extent aspartate are likely to be released from cochlear nerve terminals, supporting a transmitter role in these nerve fibres for both amino acids.     

氢清除法局部血流仪研制及氢清除曲线微机自动分析

应用新型电子器件及单片计算机,研制出一种高性能的氢清除法局部血流量测定仪;并设计了相应的计算机处理程序,自动采集氢清除曲线,用最小二乘法拟合曲线,根据拟合曲线计算出局部血流量。用该系统测定了大鼠纹状体脑血流量,拟合曲线与氢清除曲线基本上完全重合,拟合参数正确无误。血流仪设计合理,工作稳定、可靠。用微机自动对氢清除曲线进行数据采集、分析,提高了测量结果的准确性,并可及时得出实验结果。     

The immunohistochemical distribution of protein kinase C isozymes is altered in the canine brain and basilar artery after subarachnoid hemorrhage

The effects of subarachnoid hemorrhage on immunoreactivities of protein kinase C isozymes (, β, γ) were studied in canine brain and basilar artery. Mild and severe constriction of the basilar artery was shown 2 days and 7 days after hemorrhage, respectively. In control brain tissues, the isozymes showed distinct distributions and following hemorrhage, reactive astrocytes with protein kinase C staining emerged in the surface of the pons and hippocampus. The control basilar artery showed protein kinase C staining and its staining was decreased on day 7, consistent with the result of immunoblot. Our results demonstrated that subarachnoid hemorrhage induces gliosis with heavy protein kinase C staining and down-regulation of protein kinase C in the artery.     

The topographical relationships and anastomosis of the nerves in the human internal auditory canal

Introduction The anatomy of the nerves in the human internal auditory canal (IAC) has been reported by a number of authors, and there are some differences among the viewpoints of the literatures. With the development of the microsurgery and endoscopic surgery in the IAC, the study of the topographical relationship of the nerves in the human IAC becomes more and more important. The purpose of this study was to investigate the anastomosis and topographical relationship of the nerves in the human IAC. Methods In this study, we dissected 30 human temporal bones from 15 heads, and examined the topographical relationship and the anastomosis of the nerves in human IAC. Results (1) In 11 out of 30 cases (37%), the facial nerve is anterosuperior to the vestibulocochlear nerve through the whole IAC; and for the remaining 19 cases (63%), the facial nerve rotates anteroinferiorly at an angle ranging from 30° to 90°, which is in the same direction as that of the cochlear. (2) Vestibulofacial nerve anastomosis occurs in 25 cases (83%), of which 67% appears near the porus acusticus, and of which 33% appears between the lateral and intermedial portion of IAC. The diameter was about 0.5–1 mm. (3) Vestibulocochlear anastomosis occurs in 24 cases (80%) among which, some brush-like nerve fiber bundles of the cochlear nerve were seen to enter the acculus proprius directly in 13 cases. Transverse vestibulocochlear anastomosis in the fundus of internal acoustic meatus occurred in 15 cases, including two cases with more anastomosis. No vestibulocochlear nerve anastomosis was found in six cases in this study. Conclusions Our study shows that the Vestibulofacial nerve anastomosis and the vestibulocochlear nerve anastomosis do exist, and some variations appear due to individual differences. The appearance of the facial and vestibulocochlearnerves is variable but follows certain consistent patterns.     

脑电信号频带分离及频带相对强度分析方法研究

脑电信号中不同的背景节律和背景节律的抑制反映了病人的不同生理状态。本研究引入频带相对强度比的概念来评价病人的脑电背景节律状态,利用经验模态分解方法（EMD）实现脑电信号各频带的有效分离,并利用Gabor变换实现各频带信号的相对强度的计算,并在同一窗口显示脑电信号各频带节律的相对强度比,因而可以直观反映脑电信号中各背景节律的分布情况,为医生提供更丰富的临床信息。实验结果表明了所提出算法的有效性和可行性。     

三维建模的猫听皮质定位与主要分区的研究

目的研究猫听皮质的定位与主要分区的三维可视化。方法利用生物素葡聚糖胺(BDA)进行顺行追踪,建立猫听皮质区域的原始数据库,通过3D软件Amira进行重构。结果建立了猫大脑半球及其听皮质区域的数据库,将听皮质分为AⅠ、AAF、P、VP、AⅡ五区,重建了大脑半球及其主要听皮质分区的数字化解剖模型。结论将组织学技术与计算机图像处理技术相结合,可以从三维的角度来研究和重建听皮质的分区结构。