micro- and nanotechnology for neurotology, 2006, p.74

[...]... splitting sound into its frequency sub-bands without the need for analog-to-digital conversion and subsequent digital processing Since all bands are mechanically filtered in parallel, there is low latency in the output signals The simplicity of the device, high channel capability, low power requirements, and small form factor (less than 1 cm) make it a good candidate for a completely implantable bionic... 3 So  and d sB 2i X cos G /mc Vb c Sc  , 2 h Xc  X 2 i X 2Xc [c Miles /Hoy where the subscripts o and c denote the Ormia and conventional concepts shown on the left and right of figure 3, respectively So and Sc are the sensitivities of the microphones in volts/Pascal, i = Ί–1, c is the sound speed, ⌽ is the angle of incident sound, ␻c and ␻o are the resonant frequencies of the conventional and ormia... electrodes in the cochlea, and properly stimulating them, is the most likely means for restoring tonal sense An alternate approach to cochlear implants and speech coding is the ambitious goal of building an artificial co- 96 Audiol Neurotol 2006;11:95–103 chlea that truly mimics the behavior of the natural cochlea Such a device could be used for research aid for understanding cochleas (e.g., for developing mathematical... ceramics and metals, characteristically exhibit large Micromechanical Resonator Array for an Implantable Bionic Ear Easy integration with electronics Good sensitivity and dynamic range Young’s modulus and low damping [Petersen, 1982] This results in large natural frequencies (for example, a silicon cantilever, 1 mm ! 5 ␮m, resonating at about 5 kHz) and high quality factors These are desirable qualities for. .. microfabrication efforts required a special annealing step to reduce residual stress and straighten out the resonators (for microinjection molded cantilevers) Nevertheless, many engineered polymers exist that have been demonstrated as useful in critical applications, for example, polyester and polyimide Because natural frequency is so directly related to length (for a cantilever) it is easy to design multiband devices... growth factors may possibly work for the same purpose There are anecdotal reports of such trials, but no published reports at this time Acknowledgements Thanks are due to Scott S Corbett, III, for his careful review and editing of the manuscript This work was supported in part by NIH SBIR Grants DC005331 and DC04614 References Arcand B, Friedrich CR: An Articulated Package for a Cochlear Prosthesis Ann... serve as a basis for novel microphone design The principles used for developing conventional directional microphones will be described along with a discussion of the evolution and performance possibilities of the current Ormia-inspired microphones Because these new microphone designs are made possible by the use of new fabrication technologies, some of the challenges and opportunities for future advances... be constructed if it was fashioned out of a stiffened plate and supported by carefully designed hinges as shown in figure 4 [Miles et al., 2001; Tan et al., 2002] In this design, Biologically-Inspired Microphone for Hearing Aids Differential Microphone Acoustic Performance In this section, predicted results for the sensitivity and noise performance of the Ormia differential microphone (fig 4) are compared... conditions of long-term pulsatile stimulation and Ir for its strength [Spelman, 1982] Silicone rubber is used for its low toxicity, durability during long-term exposure to aqueous salt solutions and mechanical flexibility [Colas and Curtis, 2004] Substrates Cochlear electrode arrays have used silicone rubber (dimethylsiloxanes) carriers, Pt-Ir electrode contacts, and Pt-Ir wires that are insulated with fluoropolymers... nearly always has significant detrimental effects on microphone performance Myriad approaches have been developed to reduce the effects of stress on silicon microphones including the use of corrugations and stress relieving supports [see for example Scheeper et al., 1994; Bergqvist and Rudolf, 1994; Zhang and Wise, 1994; Jennan, 1990; Cunningham and Bernstein, 1997; Spiering et al., 1993] By incorporating . of seven invited papers, showcases potential applications of micro- and nanotechnologies to audiology and neurotology. Spelman reviews the development of cochlear implants and dis- cusses future. 2004, pp 658–669. Spelman FA, Clopton BM, et al: Cochlear Implant with Shape Memory Material and Method for Implanting the Same. U.S. Patent offi ce, Mi- croHelix, 1998. Spelman FA, P ngst. protocols can be perfected, this ap- proach may provide promise to provide more indepen- dent channels of information than can be provided by scala tympani arrays. Still, sorting the tonotopic arrange- ment