Recording of the Movement of the Human Basilar Membrane

Abstract

The vibrations of the human basilar membrane have been thoroughly studied by von Békésy. He used visual observation of moving silver particles on the membrane. In our preliminary experiments, we used fresh human temporal bones. The basilar membrane was exposed in the apical turn using microsurgical instruments with illumination provided by fiber optics. The cochlear fluid was moved through the round window, similar to the Békésy experiments. The movement of the basilar membrane was recorded electro-optically, using special cochlear probes described in a paper by Jako, Hickman, and Adkins at the 72nd Meeting of the Acoustical Society. Recent developments in photosensor technology, and accurate alignment of the fiber optics with the photosensors, have permitted continuing improvements in probe resolution. This technique allows instrument recording of time, phase, and frequency relations of motions at various places along the membrane while it is stimulated by sine waves, pulses, and speech. [Supported by a grant from the American Otological Society and the volunteer efforts of the participants.]