This is a prospective, multi-center, non-significant risk IDE study of evoked waveforms resulting from stimulation of the dorsal column using a closed-loop system. comprised of Medtronic hardware or off the shelf hardware, which uses recorded waveforms to adjust stimulation amplitude.

Inclusion Criteria:

1. 22 years of age or older
2. Candidate for or undergoing Medtronic SCS device trial for labeled indication*
3. Willing and able to provide signed and dated informed consent
4. Capable of comprehending and consenting in English
5. Willing and able to comply with all study procedures and visits *Candidate for or undergoing Medtronic SCS device trial for labeled indication means that a clinical decision has already been made between a physician and the patient to undergo Medtronic SCS trialing to treat the patient's chronic pain. This decision is to be made prior to discussing with the patient whether to enroll in the study.

Exclusion Criteria:

1. Implanted electrical cardiac device (e.g., pacemaker, defibrillator)
2. Currently enrolled or planning to enroll in an interventional clinical study that could potentially confound the study results (co-enrollment in an interventional study is only allowed when documented pre-approval is obtained from the Medtronic study manager or designee)
3. Currently diagnosed with a disease that may confound ability to evoke compound action potentials, e.g. multiple sclerosis, as determined by the investigator
4. Pregnant or is of child-bearing potential and unwilling to use a medically acceptable form of birth control during the study
5. Has untreated major psychiatric comorbidity, as determined by the investigator or designee
6. Trialed with a permanent implant lead and extension ("buried lead trial")