In this paper, the voice signal processing module has been designed using the micro processor for the use of fully implantable middle ear devices (F-IMEHD). The voice signal processing module for F-IMEHD should be designed to compensate for the hearing loss of hearing impaired person and have the flexibility for compensating various hearing threshold level. So, the voice signal processing module has been designed and implemented to present the various frequency characteristics using the low-power micro processor, MSP430F169. The different voice signal path to the inner ear entrance was considered so that two voice signal would be combined in-phase using an all pass filter with a constant time-delay to improve the vibration of the ossicles.

A bi-directional and multi-channel wireless telemetry capsule, 11 mm in diameter, is presented that can transmit video images from inside the human body and receive a control signal from an external control unit. The proposed telemetry capsule includes transmitting and receiving antennas, a demodulator, decoder, four LEDs, and CMOS image sensor, along with their driving circuits. The receiver demodulates the received signal radiated from the external control unit. Next, the decoder receives the stream of control signals and interprets five of the binary digits as an address code. Thereafter, the remaining signal is interpreted as four bits of binary data. Consequently, the proposed telemetry module can demodulate external signals so as to control the behavior of the camera and four LEDs during the transmission of video images. The proposed telemetry capsule can simultaneously transmit a video signal and receive a control signal determining the behavior of the capsule itself. As a result, the total power consumption of the telemetry capsule can be reduced by turning off the camera power during dead time and separately controlling the LEDs for proper illumination of the intestine.

A differential electromagnetic transducer (DET) was implemented using micro electro mechanical system (MEMS) technology for use in an implantable middle ear (IME) system. The DET is designed to have good vibration efficiency and structure that can't be interfered by the external environmental magnetic field. In order to preserve the uniform vibration performance, the MEMS technology was introduced to manufacture the elastic membrane using polyimide that is softer than silicon. Using the finite element analysis (FEA), vibration characteristics are simulated and designed so that the resonance frequency of the membrane is closed to that of the middle ear. The results of the vibration experiments of the developed DET showed excellent results. We implemented the IME system using a DET and implanted it into a dog. This showed the IME system performed well in a living body.

An electroretinogram (ERG) represents the global responses of the retina to a visual stimulus and shows accumulated responses of each layer of the retina relative to the signal processing mechanisms occurring within the retina. Thus, investigating the reaction types of each ERG wave provides information required for diagnosis and for identifying the signal processing mechanisms in the retina. In this study, an ERG signal is generated by simulating the volume conductor field response for each retina layer, which are then summed algebraically. The retina model used for the simulation is Shah's Computer Retina model, which is the most reliable model developed so far. When the generated ERG is compared with a typical clinical ERG it exhibits a close similarity. Based on changing the parameters of the ERG model, a diagnostic investigation is performed with a variation in the ERG waveform.

In this paper, for the fully-implantable middle ear hearing devices (F-IMEHD), a transcutaneous recharging system that has the function of the bi-directional signal transmission with the implant module in a body as well as recharging battery has been designed and implemented. The electromagnetic coupling method using two coils has been adopted for the transfer of electrical power to recharge internal battery of the implant module. To increase the efficiency of power transfer, the switching frequency of recharging system is determined by the consideration of the resonance of LC tank circuits. The bidirectional signal transmission between the recharging system and the implant module has been designed through the on-off keying modulation of switching signal in the recharging system and the impedance variation of LC tank circuit in the implant module. Through the demonstration of the implemented system, it has been verified that the proposed system has the performance of bidirectional signal transmission with the implant module of F-IMEHDs as well as the battery recharging.

An infrared (IR) transcutaneous remote control was designed for use in the totally implantable middle ear system. Considering the IR reflection, absorption and scattering effect of the skin, the required IR radiant intensity is calculated. After we have implemented the designed control, the transcutaneous operation experiment was carried out using a porcine skin.

A new type of electromagnetic vibration transducer for use in an IME (implantable middle ear) system is presented and evaluated by in-vitro experiment. Because the new designed transducer includes two magnets glued together with the same pole facing inside the coil, it can reduce the interference from an environmental magnetic field. And the proposed transducer exhibits a high vibration efficiency and wide frequency response. Using dead human's temporal bone, in-vitro experiments were carried out and the results showed that the proposed vibration transducer will be properly used to implantable middle ear for mild to severe hearing loss patients.