In disparate experiments, the researchers verified that ULF currents blocked sensory neuron ectopic activity, a significant driver of neuropathic pain, effectively.
Fremont, CA : Chronic pain, classified as persistent pain that lasts longer than three to six months, remains an area of considerable unmet medical need. A novel treatment that uses electrodes to provide alternating pulses of ultralow-frequency (ULF) current could help address this need. In a pilot trial, the treatment improved pain ratings by as much as 90 percent after 15 days of use. Unlike prevailing clinical neuromodulation techniques, this ULF approach also avoids tissue damage and other side effects.
Neuromodulation, the use of electrical currents to block the transmission of pain signals between neurons, has been utilised as a non-pharmacological treatment for chronic pain for decades. Prevailing technologies, however, can be invasive, have restricted efficiency, and cause side effects. Spinal cord stimulation, for instance, utilises an implanted device to produce pulsed electrical signals in the region of the spinal cord. The treatment has had restricted clinical success, only working for some patients and alleviating pain for short periods. It can also result in paraesthesia, a sensation of numbness, tingling, or burning. Previous research has also discovered the application of direct current (DC), which can effectively block the conduction of action capability (which transmit pain signals). Still, it leads to tissue damage and electrode degradation if looked after.
Notably, as the slowly cycling current waveform has a period of more than 10s, far longer than the millisecond time constant of neuronal action potentials, it efficiently mimics DC conditions but with an alternating polarity that avoids potential tissue or electrode damage. Using computational modelling, the researchers determined that the mechanism of instant conduction block at the plateau phases of the ULF waveform was similar to that produced by DC.
The team tested the efficacy of epidural ULF therapy in 20 patients with chronic lower back pain. Eighteen patients received the full treatment during five clinical visits over 15 days, with two withdrawing early due to surgical site infections. The therapy was well tolerated, with none of the patients complaining of muscle weakness or paraesthesia, marking a remarkable feat in the treatment of chronic pains.