Decreasing stimulation charge by delaying the discharge phase - comparison of efficacy for various stimulation waveforms

For chronic stimulation of nerve fibers, only charge balanced waveforms should be used. However, if the charge recuperation phase comes right after the stimulation phase, it might abolish activation of the nerve fibers that are close to the threshold level. Delaying the charge recuperation phase may eliminate this abolition effect, and thus reduce the charge required to activate nerve fibers. The objective of this in vivo study, was to determine to which extent the required stimulation charge might be decreased by delaying the discharge phase, depending on the pulse duration and the way the discharge is performed. The results demonstrated that delaying the discharge phase allows to gain more charge for shorter pulses. The difference in the gain between the waveforms with passive and active discharge is less striking. The delayed discharge does not affect much stimulation selectivity.