Scientists have managed to release the body’s most powerful painkillers by running an electrical current through the brain. The breakthrough has provided hope for sufferers of chronic migraine after it was found to reduce the pain of a headache by up to 37 per cent.
The technique, known as deep brain stimulation, or transcranial direct current stimulation (tDCS), alters the speed at which the brain’s neurons fire. This, in turn, can relieve pain. The painkillers released by the brain were endogenous opioids – the human body’s most powerful, euphoria-inducing painkillers that are very similar to opiates such as morphine.
The new research, conducted at the University of Michigan, found that just a very small current – of two milliamps – was enough to have the effect.
Thirteen patients with chronic migraine – defined as least 15 attacks a month – had electrodes were placed above the motor cortex – the part of the brain responsible for voluntary movement.
After 10 sessions over four weeks, the average person’s pain threshold had increased by 37 per cent after four weeks.
The effects were cumulative and kicked in after about four weeks of treatment, said Alexandre DaSilva, assistant professor at the U-M School of Dentistry and lead author of the study, which appears in the journal Headache.
‘This suggests that repetitive sessions are necessary to revert ingrained changes in the brain related to chronic migraine suffering,’ he said, adding that study participants had an average history of almost 30 years of migraine attacks.
By boosting the release of natural painkillers, it’s hoped chronic migraine sufferers would be less reliant on medication, therefore reducing the side effects and the risk of addiction.
Other studies have shown that stimulation of this part of the brain reduces chronic pain. However, this study provided the first known mechanistic evidence that tDCS of the motor cortex might work as an ongoing preventive therapy in complex, chronic migraine cases, where attacks are more frequent and resilient to conventional treatments, DaSilva said.
While the results are encouraging, any clinical application is a long way off, DaSilva said.
‘This is a preliminary report,’ he said. ‘With further research, noninvasive motor cortex stimulation can be in the future of adjuvant therapy for chronic migraine and other chronic pain disorders by recruiting our own brain analgesic resources.’
The research, performed in conjunction with scientists from Harvard University and the City College of the City University of New York, also tracked the electric current flow through the brain to learn how the therapy affected different regions.
This was done using a high-resolution computational model. They correctly predicted that the electric current would go where directed by the electrodes placed on the subject’s head, but the current also flowed through other critical regions of the brain associated with how we perceive and modulate pain.
‘Previously, it was thought that the electric current would only go into the most superficial areas of the cortex,’ DaSilva said. ‘We found that pain-related areas very deep in the brain could be targeted.’