Transcutaneous electrical nerve stimulation (TENS) is widely used for chronic pain. Recent studies showed frequency-specific microcurrent (FSM) resonant therapy was safe and effective in patients with non-specific chronic low back pain. However, there was no prospective, double-blinded randomized controlled trial to validate the clinical applicability. The goal of this trial is to verify safety and efficacy of FSM using a TENS device, Dragon Waves Resonant Home Care Electronic Nerve Stimulator-DW1330,(Taiwan Resonant Waves Research Co, Taiwan R.O.C), in 60 patients with non-specific low back pain.

Several studies showed that frequency-specific microcurrent (FSM) resonance therapy delivered by transcutaneous electrical nerve stimulation (TENS) device is safe and effective in patients with non-specific low back pain. The regiment of variable-frequency combination (1-10000 Hz or 1-20000 Hz), continuous use for 36-60 mins per day and 30 to 180 days per session has been proven to be safe. To validate the clinical applicability of FSM by using a TENS device, DW-1330 (Taiwan Resonant Waves Research Co., Taiwan R.O.C.), a prospective, randomized, double-blinded trial is proposed. Investigators are going to recruit 60 patients with non-specific low back pain for at least 3 months. Clinical assessments include Numerical Rating Scale (NRS), Oswestry Disability Index (ODI), EuroQol instrument (EQ-5D), Pressure pain threshold (PPT), and Heart rate variability (HRV). The 60 patients were double-blinded, 1:1:1-randomly-distributed into 3 groups using different variable-frequency combinations: (1) Variable-frequency combination 1 (2) Variable-frequency combination 2 (3) Control(Placebo). During the surveillance period, a total of 2 visits and a telephone follow-up is set at Time point = 0, 2(telephone) and 4 week after recruitment. The primary endpoint is the change of NRS. The secondary endpoint is change of Heart rate variability (HRV). The safety evaluated index is the adverse event rate for all 3 groups.

Inclusion Criteria:

1. Age between 20-80 years old, male or female.
2. Cases with normal psychological and communication functions who can cooperate with our study.
3. Cases who are willing to sign permits and cooperate with our study including follow up and examination.
4. Cases with complete clinical data and willing to accept investigation.

Exclusion Criteria:

1. Cases who diagnose pregnancy within 12 months before included.
2. Cases who diagnose with malignant disease.
3. Cases with a history of epilepsy.
4. Cases who diagnose with fracture without fixation.
5. Cases who diagnose with impaired sensation or psychological function.
6. Cases whose skin condition is not feasible to accept treatment.
7. Cases with pacemaker.
8. Cases who allergic to the conductive medium
9. Cases with a major psychiatric disorder such as schizophrenia or bipolar disorder.
10. Cases with severe visual or auditory disorder.
11. Cases who cannot communicate with the Mandarin language.
12. Other mental diseases are not suitable assessed by the PI