An electrical stimulation system is disclosed, which comprises a processor configured and arranged to (i) obtain a biosignal of patient, (ii) alter at least one stimulation parameter of the electrical stimulation system in response to the biosignal, and (iii) deliver an electrical stimulation current to one or more selected electrodes of the electrical stimulation system using the at least one stimulation parameter. In some embodiments, a power spectrum is determined from the biosignal. In some embodiments, the biosignal comprises at least two different biosignals measured at the same or different locations on the patient and a coherence, correlation, or association between the two biosignals is determined.
