Figure 3:

Energy efficiency and theoretical battery life are optimized by lengthening the pulse width to the value of the chronaxie and using a single directional segmented contact. A. Moderately long pulses (specifically, the chronaxie) optimize energy efficiency, while charge increases linearly with pulse width. B. Energy is reduced substantially by dose-equivalent stimulation (same spread in the intended direction) with one segmented contact. Theoretical battery improvements when switching to a single contact are slightly greater at short pulse widths due to poor efficiency with short pulses. C. For a given spread in the intended direction, single contact stimulation at a moderately long pulse width maximizes theoretical battery life.