The Allocation of Engineering Resources

UCSF's small engineering group was already heavily committed: designing and producing new patient electrodes, a percutaneous connector system, a matching 4-channel trans-cutaneous transmitter-receiver, and matching compact portable speech processor -- to be used by the few research patients after they had completed 3-6 months of tests using the per-cutaneous system.

In addition to this, a "clinical version of this implant" was being developed and produced "under-the-gun" by the same engineering group for distribution to a substantial number of hospitals around the U.S. and in Britain!  This system was similar to the system that was to, and did, replace the few research patients' percutaneous system.  M White later learned from Mike Hirshorn, and others, that this "clinical implant-system" had been promised by R. Schindler to other clinics well before our formal NIH-sponsored, cochlear-implant group had a chance to build, let-alone test, any "truly new" speech processing systems.

The "clinical system" had been promised to otolaryngologists around the U.S. within the first year of the inception of our NIH human-implant grant.*   Mike Hirshorn had found that U.S. otolaryngologists were relatively uninterested in other cochlear implant systems at the time because they had been promised UCSF devices by R Shindler.  This allocation of engineering resources had a major impact on the research at UCSF.  It should be noted that many of the researchers in the UCSF group did NOT consider the multichannel analog system, described here, as "truly new."  [Reasons: (1) R Michelson and R Schindler had implanted patients with such scala tympani multichannel analog systems long before (and after) the start of our NIH grant (1978).**  (2) Don Eddington was already formally testing a similar analog system in Utah. (3) We felt that Helmholtz and Bekesy, had they had the electronic technology, would have naturally proposed such a system based-on their beautiful understanding of the cochlea.]  

*  In this investigators opinion, it is quite possible that the rivalry between the UCSF and the House Institute surgical staff was at least partially responsible for the many extra tasks that the engineering group was assigned.

** It should be noted that almost all early multichannel analog systems used unisolated, voltage-controlled stimulators.  To create a truly multi-channel system required that each channel's stimulator be electrically isolated from the other channels.  It should be noted that the electrode contact impedances were far larger than the tissue and perilymph impedances in multichannel implants (see //TBD).  As a consequence, defining such systems using unisolated channels as "multichannel" is questionable at best.  In contrast, Don Eddington's real-time multichannel analog system did use channel-isolated, current-controlled stimulators -- as did UCSF's 8-channel non-real-time speech processing laboratory system. UCSF's portable, take-home device had isolated channels, but used voltage drivers. Whereas, UCSF's table-top real-time systems had isolated current sources (as well as isolated voltage sources as an option, for comparison purposes). See pp. 166 of Merzenich, 1983 for a diagram of one commonly-used configuration of UCSF's table-top real-time 4-channel analog processor. An aside:  I remember hearing that Dr. Hall and Dr. James Flanagan from Bell Labs designed and built one or more optically-isolated current sources in the 1960s for cochlear implant research that they had conducted with Blair Simmons.  When I was doing the same thing 10 years later for animal experiments, I certainly felt in good company!