Energetic analysis for self-powered cochlear implants

Electrical Signal Modeling in Cochlear Implants. Study of Temperature and Humidity Effects

The present paper discusses the climatic effects of humidity and temperature on cochlear implant functioning and the quality of the electrical sound signal. MATLAB Simulink simulations were prepared, offering insights into signal behavior under such climatic parameter changes. A simulation setup of the cochlear implant was developed, where a source type selection was used to change between a voice recording and a “chirp” sound. In addition, a DC blocking filter was applied to the input signal. A simulation code, with the application of the climatic influence via the air attenuation function, was developed. Thereby, the attenuation of temperature and humidity in the sound atmospheric circulation of the input signal, at T = 0 °C and RH = 0% and at T = 36 °C and RH = 40% was graphically represented. The results of the electrical pulse generator for each of the eight channels, with the IIR filter, Gaussian noise, temperature variation, humidity influence, and control of denoise block activity, were thus obtained.

Optimization of kinetic energy harvesters design for fully implantable Cochlear Implants

Fully implantable Cochlear Implants (CIs) would represent a tremendous advancement in terms of quality of life, comfort and cosmetics, for patients with profound sensorineural deafness. One of the main challenges involved in the development of such implants consists of finding a power supply means which does not require recharging. To this aim an inertial Energy Harvester (EH), exploiting the kinetic energy produced by vertical movements of the head during walking, has been investigated. Compared to existing devices, the EH needs to exploit very low frequency vibrations (<2.5 Hz) with small amplitude (<9 m/s(2)). In order to maximize the power transduced, an optimization method has been developed, which is the objective of this paper. The method consists in calculating the dynamical behavior of the EH using discrete transforms of experimentally measured acceleration profiles. It is shown that the quick integration of the second order dynamical equation allows the use of computationally intensive optimization techniques, such as Genetic Algorithms (GAs). The robustness of the solution is also evaluated.