1982 Volume 25 Issue 2 Pages 75-78
Implantable microphone for total implantation of the cochlear prosthesis was developed by utilizing a piezoelectric ceramic element. As the ceramic element generates electric potential in response to the mechanical distortion of its bimorph structure, it can be used as a pick-up of the vibration of the tympanic membrane by touching it to the head of the malleus. The tympanic membrane works a diaphragm of microphone, and there is no need to implant a diaphragm. Therefore, by this method it is possible to design a miniaturized microphone for implantation. The ceramic element is good at durability and can easily be coated with biocompatible material with least reduction of its performance.
Sensitivity and frequency response of this implantable microphone were studied with three human temporal bones preserved in 10% formaldehyde solution. The results showed that their best sensitivities in the three specimens ranged from-5 dB to -63dB re V/Pa for 1kHz, which warranted the possibility of this method in practical use.