Subject matter includes a method comprising: applying a first electrical signal to a subject； identifying a proposal to change the first electrical signal to a proposed second electrical signal； calculating at least one parameter of the proposed second electrical signal； and determining whether the calculated at least one parameter violates any rules. If the at least one parameter does violate any of the rules, then the method further comprises iteratively modifying one or more features of the proposed second electrical signal to arrive at a modified second electrical signal that complies with the rules. If the at least one parameter does not violate any of the rules, then the method further comprises applying the proposed second electrical signal to the subject.
