Cochlear implant stimuli use charge-balanced biphasic pulses at around 20 pulses per second.

Evidence

The stimulus was a train of charge-balanced biphasic pulses presented at a rate of 19.9 pulses per second (pps) (He et al. 2010 ), with 50 or 60 μs phase duration, and 2.1 μs interphase gap presented repeatedly via monopolar stimulation mode. A phase duration of 60 μs was used only when the subject could not reach the MCL with 50 μs. — Dijk, Pim van, Physiology, Psychoacoustics and…, 1461