A method of operating an implantable neuromodulator includes calculating an index for each of a plurality of modulation parameter sets, wherein each modulation parameter set includes a respective plurality of modulation parameters from which the respective index is calculated, serially conveying electrical modulation energy to a patient in accordance with each of the plurality of modulation parameter sets, causing the patient to perceive paresthesia in response to the conveyance of the electrical modulation energy to the tissue in accordance with one of the plurality of modulation parameter sets, identifying the calculated index for that one modulation parameter set as a perception threshold index based on the perceived paresthesia, and storing the identified perception threshold index. The method may also include determining a new modulation parameter set based on the identified perception threshold index, and conveying electrical modulation energy to the tissue in accordance with the new modulation parameter set.
