Can we use interleaved high-rate multi-channel stimulation without creating
problematic inter-channel interactions?

Quotes from the Early Literature:

• Early Neurophysiological Evidence was extremely positive (too positive!): excerpt from p. 334 of "Cochlear Implant: The Interface Problem," Merzenich & White, 1977: Chapter in Functional Electrical Stimulation Vol. 3, 321-340.  This figure also illustrates the inter-pulse-intervals that UCSF tested.  Such short inter-pulse intervals were tested because we believed that they could be potentially useful for speech processors . 

• Psychophysical Evidence was initially too positive also:  See Eddington DK, Dobelle WH, Mladefovsky MG, et al: Auditory prostheses research with multiple channel intracochlear stimulation in man. Ann Otol Rhinol Laryngol, 1978 vol. 87 (supplement 53: pp 5-38)

• However in "Multichannel Cochlear Implants: Channel Interactions and Processor Design," White, Merzenich, & Gardi, 1984, the authors found that channel interactions can occur during non-simultaneous stimulation of 2 or more channels.  Excerpt 1 is a plot of data from a patient that exhibited the largest and longest-time-constant interactions to non-simultaneous stimulation.  Note that the 2 electrodes were monopolar and they were separated by only 2 mm.

• Fortunately such interactions are far less severe than interactions that occur during simultaneous stimulation.

• Furthermore, interactions due to non-simultaneous stimulation occur only with some subjects, some electrode geometries, and when inter-electrode distances are relatively small:  see excerpt 2,  excerpt 3, and excerpt 4 from White, Merzenich, and Gardi (1984). 

• The authors go on to summarize some of these results on p. 501.