Fixed-Site High-Frequency Transcutaneous Electrical Nerve Stimulation Decreases Both Chronic Pain and Periodic Leg Movements--Evidence for Decreased Central Excitation and Enhanced Central Inhibition?

Periodic leg movements (PLMs) are repetitive movements occurring every five to 90 seconds. PLMs are associated with restless leg syndrome (RLS) and are elevated in chronic pain. Although the neurologic generator for PLMs is unknown, evidence points to increased central nervous system (CNS) excitability. Consistent with this mechanism, prescription opioids are used to treat RLS. Fixed-site high-frequency trans-cutaneous electrical nerve stimulation (FS-TENS) is an emerging form of TENS in which the stimulator is designed for a predetermined location rather than co-localization with the patient's pain. FS-TENS is believed to relieve chronic pain by decreasing central sensitization and enhancing descending inhibition through opioidergic pathways. We evaluated a real-world database of FS-TENS device use for chronic pain. The device and companion smartphone app collect dosage, demographics, pain characteristics, and sleep data (actigraphy). Responders had a [greater than or equal to]15% reduction in composite pain from baseline to 10 weeks (average pain intensity and interference with sleep, activity, mood; 11-point NRS). Participants with RLS or baseline PLM/h