Experiments in comparative hearing: Georg von Békésy and beyond

Georg von Békésy was one of the first comparative auditory researchers. He not only studied basilar membrane (BM) movements in a range of mammals of widely different sizes, he also worked on the chicken basilar papilla and the frog middle ear. We show that, in mammals, at least, his data do not differ from those that could be collected using modern techniques but with the same, very loud sounds. There is in all cases a major difference to frequency maps collected using low-level sounds. In contrast, the same cannot be said of his chicken data, perhaps due to the different roles played by the BM in mammals and birds. In lizards, the BM is not tuned and it is perhaps good that Békésy did not begin with those species and get discouraged in his seminal comparative work.     

Békésy测听的临床应用

报告对20耳正常耳和由不同病因导致听力损害的123耳进行Bekesy测听的结果,证实Jerger对测听描记曲线进行分型基本符合临床表现,尤对判断蜗内性聋及蜗后性聋具有重要的定位价值;对蜗内性聋加掩蔽测试更能表现重振特性。     

Békésy自动描记听力计使用法

一、Békésy自动描记听力计自动描记听力计是以它的发明者Békésy的名字命名的。这种仪器利用一个频率范围从100—10000Hz的拍频振荡器发出脉冲的或连续的纯音讯号,脉冲音讯号持续200ms,中断200ms(亦有“开”260ms,“关”260ms,上升下降时间40ms)。讯号频率的转换用一个电动马达来控制,它可以在100—10000Hz(或8000Hz)的频率范围内以从低到高的形式来增加讯号的频率。即扫频方式。电动马达也可以被阻断而由检查者来操纵频率的转换装置,以便对听力计频率范围内的任何单一频率进行连续测试,即固定频率的方式。纯音讯号的强度由受试者操纵的衰减器马达手控开关来控制。衰减器马达使测试讯号的强度均匀而平稳的增加,当病人听到声音的时候,他按压手控开关,使衰减器马达倒转而引起讯号的强度减低。当病人听不到声音的时候,将手控开关放松,则衰减器马达使讯号的强度重新     

Simultaneous cancellation of air and bone conduction tones at two frequencies: extension of the famous experiment by von Békésy

Cancellation experiments between air conduction (AC) and bone conduction (BC) tones were conducted at two frequencies (0.7 and 1.1 kHz) and three levels (40, 50, and 60 dB HL) in three subjects. The tests were divided into three categories: (1) single tone cancellation, (2) simultaneous cancellation of two tones, and (3) cancellation of one tone while a disturbing tone was present. In total, each subject performed twelve cancellation tasks. The hypothesis is that the AC and BC sound transmission behaves as linear systems and they both excite the basilar membrane in the cochlea similarly. The cancellation results are presented as the deviations from this hypothesis; except for a few larger deviations, the intrasubject deviations were generally less than 0.5 dB and 5 degrees. The results from all three test categories indicate that the hypothesis of linear transmission systems and similarity of cochlear stimulation by AC and BC holds. However, due to the subjects' limited ability to conduct optimal cancellation and to imperfect methodology and equipment, the small deviations from perfectly linear cancellation that were observed do neither conclusively prove nor refute the possibility of small differences in the cochlear processing of AC and BC sound. Nonetheless, it is clear that if such differences in the processing of the two stimuli exist, they are small in magnitude.     

Long-term measurements using home audiometry with Békésy’s technique

Objective: To examine the efficacy of fixed-frequency Békésy’s home audiometry to assess hearing fluctuation and treatment outcomes in patients with subjectively fluctuating hearing loss. Design: SMAPH, a software audiometry program for Windows, was installed and calibrated on laptop computers. Békésy’s audiometry was carried out daily in the patients’ homes, using sound-attenuating earphones. Study sample: Seventeen patients with previously or currently subjectively fluctuating hearing loss. Five patients received of treatment for their conditions during the measurement period. Results: Measurement periods ranged from 6 to 60 days. Varying degrees of compliance were seen, some patients measuring less than 50% of the days, others measuring every day. Based on their long-term measurements the patients were classified into three groups: patients with stable recordings, with fluctuating low-frequency hearing loss, or with fluctuating high-frequency hearing loss. In the patients with stable recordings, significant test–retest differences were seen below 10?dB at frequencies 0.125–8?kHz. Conclusions: Home audiometry with Békésy’s technique can be used to evaluate disease activity and to monitor hearing results after therapy.     

Determination of Recruitment with von Békésy's Audiometer Above the Threshold

Examinations were made in order to determine the recruitment above the threshold by means of Von Békésy's audiometer. The sound of this was adjusted by the patient to the different pure tones 250, 500, 1000, 2000, 4000 cps (40 dB above the thresholds) given to the opposite ear at the same frequencies similarly to the loudness balance test. The sound intensity of the Von Békésy audiometer was altered by the patients within a certain intensity range and registered automatically. The magnitude of the intensity range depends on the capacity of loudness perception. In cases of recruitment the patient is able to observe smaller differencies of the loudness than normal persons therefore the intensity ranges are also smaller in such cases. We have achieved better results by this method than by the threshold measurements according Von Békésy applied usually.

RéSUMé

Des examinations ont été entreprises avec l'audiomètre de Von Békésy pour déterminer la regression au-dessus du seuil. Le principe de la méthode est que le malade ajuste le ton de l'audiomètre de Von Békésy au pur ton donné à fréquence identique 40 dB au-dessus du seuil dans l'oreille contralatéral. Au cours du test le malade change le ton de l'audiomètre de Von Békésy entre certaines valeurs d'intensité. L'amplitude de cette différence d'intensité dépend de la perception de sonorité du malade. En cas de régression la perception de petites différences de sonorité est plus prononcée et pour cela les excursions sont aussi plus petites. La preuve a été obtenu dans des sujets à ouie normale et dans des malades avec surdité de perception.     

Correspondence amongst microstructure patterns observed in otoacoustic emissions and Békésy audiometry.

Similar patterns of microstructure have been reported in normal ears for Békésy threshold recordings and various forms of otoacoustic emissions (OAE). It has been suggested that they have a common origin associated with the amplifying function of the outer hair cell system and wave interactions occurring within cochlear mechanics. Fine-frequency Békésy audiometry was conducted in ten normal ears and its microstructure was compared with that recorded using two OAq techniques: stimulus frequency (SFOAE) and distortion product (DPOAE). All sweeps encompassed the frequency range from 992 to 2000 Hz in 16-Hz steps. The same probe was used for all Békésy and OAE recordings to eliminate transducer effects. SFOAEs were obtained with stimulus intensities of 0, 3, 6 and 9 dB. DPOAEs were obtained for 2F1-F2 with primary levels (L1/L2) of 40/30, 45/35, 50/40 and 55/45 dB. Reliable microstructure was recorded in all ears. Mean values of microstructure peak spacing ranged from 5.6 to 9.3 per cent amongst methods, consistent with published data. Microstructure was similar within each OAE method for different stimulus intensities for each subject. However, comparisons between Békésy and OAEs, or between OAE methods, did not show the strong correspondence that would be expected if there were a simple common origin to the microstructure. There was weak support for the expected correspondence between Békésy and SFOAE, but no support for any correspondence between Békésy and DPOAE. It is concluded that the various forms of microstructure cannot be explained by a simple common origin.     

纯音听力计与自描(Békésy)听力计测定的听阈对比

听阈测定中,工具的不同是阈值变化的主要原因之一。目前,通用的测听工具是纯音听力计和自描听力计。作者从115例、年龄为25～63岁的男性船厂工人的听闹测定中,进行了这二种听力计的阈值对比。采用的纯音听力计的Madsen OB 60,耳机为配有MX-41/AR外垫的TDH-39M型。自描听力计为Demlar 120型,耳机为配有上述外垫的TDH-49 P型。二种听力计分别按ISOR 389(1964)和ANSI S 3.6(1969)标准校定,但经同一仿真耳校正,其精确度与稳定性均优于±1分贝。衰减范围:纯音听力计从+10分贝起以5分     

应用骨导听觉脑干电反应方法验证Békésy蜗管行波学说

1952年 Békésy提出蜗管行波学说 ,即根据蜗管内流体力学特性 ,行波起源于耳蜗底转基底膜张力最大的部位。本文通过骨导听觉脑干电反应 ( ABRs)方法对耳蜗内行波的传播时程进行研究 :1测定 11名正常听力志愿者 ( 18～ 2 6岁 )的平均骨导阈值 ;2对 2 0名 16～ 2 6岁的正常听力健康人测定气导和骨导 ABR潜伏期 ;3测定高频通过白噪声 (高通带滤波噪声 )掩蔽下6名听力正常志愿者 ( 2 2～ 65岁 )骨导 ABR:先在无掩蔽条件下测定 波潜伏期 ,给声同时用不同频带宽度高通带滤波噪声掩蔽 ,其下限频率依次为 :7.7k Hz,6.4 k Hz,5.3k Hz,4 .4 k …     

Confirmation of G. von Békésy's theory of paradoxical wave propagation along the cochlear partition by means of bone-conducted auditory brainstem responses

In order to investigate the propagation time of the traveling wave in the cochlea after bone-conduction stimulation of the inner ear, bone-conducted auditory brainstem responses (ABRs) were recorded in 6 normally hearing subjects after masking the basal cochlear region using high-pass filtered noise. As in air-conducted ABRs, Jewett V wave latency is delayed corresponding to the propagation time of the traveling wave front traversing the desynchronized hair cell region. These results support the theory of paradoxical wave propagation proposed by von Békésy in 1952, who postulated that wave motion always starts from the stiffest part of the basilar membrane, independent of the location of the vibrating force. In addition, we also found a latency delay of the Jewett V wave of bone-conducted ABRs in 8 patients with high-frequency hearing loss which corresponded to the severity of their hearing impairment.     

Georg von Békésy教授传略

Georg von Békésy(1899~1972)是匈牙利的生物物理学家,1899年6月3日出生于匈牙利布达佩斯,父亲Alexander von Békésy是匈牙利外交家,母亲Paula Mazaly也是匈牙利人,Georg在3个孩子中排行第一.Georg von Békésy一生致力于听力研究,成就辉煌.他因对听觉系统研究的重大贡献,获得1961年的诺贝尔生理学或医学奖.