Keywords: Hearing-loss

Abstract: The use of cochlear implants as an aid to neurosensory deafness is becoming an established procedure. The transmission of a processed speech signal is accomplished either transcutaneously via radiofrequency (sensitive to eletomagnetic interference) or percutaneously by connector coupling (major risk of infection). To oveacome these disadvantages, an infrared (IR) system for transmission through the tympanic membrane was devised and tested. The transmitter/ receiver consisted ofan IR light emitting diode (LED; 920nm) and a photovoltaic cell. The LED was placed inside the auditory canal of four dogs and the photovoltaic cell in the tympanic cavity over the cochlear promontory. A sinusoidal signal modulation was applied to the LED. The emitted signal was detected undistorted after crossing the tympanic membrane, with an average absorbance of 20%. The authors conclude that the tympanic membrane may be used as a translucent sealed interface to transmit data in the audio range to the middle and inner ears, with small power loss, good frequency response, and immunity lo interference.