Feldmann H
HNO-Klinik, Universität Münster.
Laryngorhinootologie. 1997 Jul;76(7):428-34. doi: 10.1055/s-2007-997457.
Weber's and Rinne's tuning-fork tests were for a long time considered unreliable, as they often seemed to yield inconsistent results. The sources of error were manifold and lay in the fields of physics, physiology, pathophysiology, and psychology. When the problems came to be understood, more sophisticated instruments and techniques were developed.
The prongs of the tuning fork were fitted with clamps to deaden overtones when it was put into vibration (Politzer 1870). By shifting the clamps along the prongs the tone of the tuning fork could be varied in a range up to one octave (Könlg 1878). A knob of hom or metal was fixed to the end of the shaft to ensure a good coupling to the skull when testing bone conduction (Lucae 1886). A small hammer fixed to the shaft and driven by a spring would activate the tuning fork with reproducible strength (Lucae 1899). A wedge-shaped figure drawn on the lateral surface of the clamps would allow one to optically control the amplitude of vibration (Gradenigo 1899).
The time during which a patient hears the tuning fork after it has been struck as compared to that of a normal hearing subject was measured as parameter of hearing acutiy (v. Conta 1864). A number of tuning forks at intervals of one octave each were assembled in sets to cover the whole frequency range of hearing. The most sophisticated example of these sets was the Bezold-Edelmann continuous tone series (1894). It comprised ten tuning forks with sliding clamps, two pipes of the organ type, and a Galton whistle. With this instrumentation it was possible to test the whole range of hearing.
The results of testing the hearing via air conduction and bone conduction measured in duration and calculated as percentage of normal hearing were presented in charts (Hartmann 1885, Gradenigo 1893) which can be considered precursors of modern audiograms. The evolution of these instruments and methods is described in detail and illustrated by exhibits from the museum.
长期以来，韦伯氏和林纳氏音叉试验被认为不可靠，因为其结果常常似乎不一致。误差来源是多方面的，涉及物理、生理、病理生理及心理学领域。当这些问题被认识后，便开发出了更精密的仪器和技术。
音叉的叉臂安装了夹子，以便在音叉振动时消除泛音（波利策，1870年）。通过沿叉臂移动夹子，音叉的音调可在高达一个八度的范围内变化（孔尔格，1878年）。在音叉柄端固定一个角质或金属旋钮，以确保在测试骨传导时能与颅骨良好耦合（卢卡埃，1886年）。一个固定在音叉柄上并由弹簧驱动的小锤子，能以可重复的力度激活音叉（卢卡埃，1899年）。在夹子侧面绘制的楔形图案，可让人通过视觉控制振动幅度（格拉代尼戈，1899年）。
测量患者在音叉被敲击后听到声音的时间，并与听力正常的受试者进行比较，以此作为听力敏锐度的参数（冯·孔塔，1864年）。将一系列每隔一个八度的音叉组装成组，以覆盖整个听力频率范围。这些组中最精密的例子是贝佐尔德 - 埃德尔曼连续音系列（1894年）。它包括十个带有滑动夹子的音叉、两个风琴管类型的管子和一个高尔顿哨子。借助这套仪器，可以测试整个听力范围。
通过气导和骨导测试听力的结果，以持续时间来测量，并计算为正常听力的百分比，呈现在图表中（哈特曼，1885年；格拉代尼戈，1893年），这些图表可被视为现代听力图的前身。本文详细描述了这些仪器和方法的演变，并通过博物馆展品进行说明。
