Scientists Use Light and Sound to Reduce Pain

By Pat Anson, Editor

British researchers have found that pain can be significantly reduced if the brain if “tuned in” to a particular frequency, a discovery that could potentially lead to new visual and sound therapies to treat chronic and acute pain.

"This is very exciting because it provides a potentially new, simple and safe therapy that can now be trialed in patients,” said Professor Anthony Jones, director of the University of Manchester Pain Consortium. “The potential is for this to be another treatment for chronic pain.”

Jones and his colleagues say nerve cells in different parts of the brain communicate with each other using different frequencies.  

Nerves in the front of the brain associated with a placebo analgesic effect are tuned in at 9-12 cycles per second, and apparently use that frequency to influence how other parts of the brain process pain.

To test their theory, researchers had 64 healthy volunteers wear goggles and headphones, and exposed them to different flashing lights and sounds while heat pain was induced with a laser on the back of their arms.

The volunteers who were exposed to an alpha frequency at 9-12 cycles felt significantly less pain than those who were exposed to other light and sound levels.

“This study provides new evidence that visual and auditory entrainment in the alpha range can influence the perception of acute pain independently of arousal and negative emotional influences,” the researchers said. “Overall, visual entrainment produced a larger effect than auditory entrainment in the mid- and lower alpha frequencies. This provides further evidence that external stimulation can modulate pain perception and requires further study to ascertain its relevance to clinical pain states.”

Further studies are needed to test the effectiveness of alpha wave therapy in patients with different pain conditions. Researchers say the simplicity and low cost of the technology should facilitate more clinical studies.

"It is interesting that similar results were obtained with visual and auditory stimulation, which will provide some flexibility when taking this technology into patient studies,” said Dr. Chris Brown, a lecturer in Psychology at The University of Liverpool who was involved in the research. “This might be particularly useful for patients having difficulty sleeping because of recurrent pain at night."

The study, which was self-funded as part of a PhD project, is being published in the European Journal of Pain.