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1857304 
Journal Article 
Review 
Basics of energy supply to completely implantable hearing aids for sensorineural hearing loss 
Baumann, JW; Leysieffer, H 
1998 
Yes 
HNO
ISSN: 0017-6192
EISSN: 1433-0458 
46 
2 
121-128 
German 
9556710 
WOS:000072436500007 
A fully implantable hearing aid consists of a sound receptor (microphone), an electronic amplifier including active audio-signal processing, an electromechanical transducer (actuator) for stimulating the ear by vibration, and an energy source. The energy source may be either a primary cell or a rechargeable (secondary) cell. As the energy requirements of an implantable hearing aid are dependent on the operating principle of the actuator, the operating principles of electromagnetic and piezoelectric transducers were examined with respect to their relative power consumption. The analysis showed that the energy requirements of an implantable hearing aid are significantly increased when an electromagnetic transducer is used. The power consumption of a piezoelectric transducer was found to be less than that of the electronic components alone. The energy needed to run a fully implantable hearing aid under these conditions would be 38 mWH per day. Primary cells cannot provide the energy needed for a minimum operation time of 5 years (70 WH), and therefore rechargeable cells must be used. A theoretical appraisal was carried out on nickel-cadmium, nickel-metal hydride, and lithium-ion cells to determine their suitability as well as to assess the risks associated with their use in an implant. Safety measures were drawn up from the results. Ni-MH cells were found to be the most suitable for use as an energy source for implantable hearing-aids because they are more robust than Li ion cells and their storage capacity is double that of Ni-Cd cells of similar size. 
cochlea-amplifier implant; ear; electromechanical transducer; hearing aid; hearing improvement; hearing loss; implant; implantable hearing aid; implantable microphone; implantable rechargeable battery; inner ear stimulator; mastoid; medical device; middle ear; ossicles; ossicular chain; piezoelectric transducer; sensorineural hearing loss; TICA; transcutaneous energy transmission; Tuebingen implant