Perception of sound through direct oscillation of the stapes using a piezoelectric ceramic bimorph

An ossicular vibrator of original design made from a piezoelectric ceramic bimorph was described. To test its effectiveness, the vibrator was temporarily implanted during tympanoplasty in four selected patients who had suffered extensive damage to the middle ear. By use of a special applicator, the vibrator was connected to either the stapes or the columella and was then excited by pure tone and speech signals. The subjects could hear well with the vibrator and distinguish speech signals. Thus a vibration threshold curve and a vibratory speech discrimination score were obtained. Comparing these with the results of conventional audiometry, the vibrator proved to be a highly efficient sound-conducting device. This study furthermore calls attention to some practical applications of this device, particularly to the possibility of implanting the vibrator as part of an implantable hearing aid.