Speech processors for cochlear prostheses

The authors review considerations in the design of speech processors for cochlear prostheses. To illustrate issues of processor design, two fundamentally different processing strategies are described in terms of the information that they can convey and in terms of how they might perform under various conditions on nerve survival. A summary is presented of clinical tests comparing these strategies in eight implant patients. Key findings from the comparison studies are that (a) one processor (the interleaved pulse processor) is clearly superior for patients with psychophysical signs of poor nerve survival, (b) another processor (the compressed analog processor) may be superior for patients with signs of good survival, and (c) different processing strategies can produce widely different outcomes for individual patients. Future directions in the future development of speech processors for cochlear prostheses are outlined