A simple, non-invasive technique providing low-level electrical stimulation of the brain produces significant pain-reducing effects in humans, a new study has found.
According pain researchers at Stanford University, with further research and development, transcranial electrostimulation (TES) could provide a valuable, non-drug approach to reducing pain and the need for pain medications.
In the study, ultraviolet light was used to create a small, painful area of sunburn on the upper thigh in healthy volunteers.
The researchers used this technique, a standard model used to test the pain-relieving effects of drugs, to evaluate the effects of TES on pain responses.
In TES, a mild electrical current is delivered through electrodes placed around the patient's head. Two different stimulation frequencies were tested: 60 and 100 hertz (Hz).
The subjects felt only a mild tingling sensation during electrical stimulation.
The pain-relieving effects of TES were evaluated by means of sensory testing, with hot temperature and mechanical force applied to the sunburned skin and to undamaged skin.
The results showed that TES significantly reduced pain responses in both sunburned skin and non-burned skin in a frequency-dependent manner.
Only 60 Hz TES was effective, while 100 Hz TES had little or no pain-relieving effect.
"The effects of TES on both heat and mechanical pain suggest that it may be able to diminish the exaggerated responses of the central nervous system to painful stimuli, which play an important role in the development and maintenance of many pain states," lead author Dr. Vladimir Nekhendzy stated.
"However, there is a possibility that TES could provide lasting benefits to patients receiving multiple treatments," Nekhendzy added.
Dr. Felipe Fregni of Harvard University wrote although confirmatory research is needed, the new study "adds important data for the development of non-invasive cortical stimulation as an analgesic method".
"The possibility of non-pharmaceutical approaches to pain relief is very exciting," Dr. Steven L. Shafer of Columbia University, Editor-in-Chief of Anaesthesia and Analgesia, said.
"The next step is to move beyond these volunteer trials to see if transcranial electrostimulation is effective in patients suffering from chronic pain," he added.
The findings have been published in the November issue of Anaesthesia and Analgesia, official journal of the International Anesthesia Research Society (IARS).