A particularly prevalent pattern of brain activity known as alpha waves strongly relates to the body’s susceptibility or resilience to pain, according to researchers at the University of Birmingham in the United Kingdom and the University of Maryland School of Dentistry (UMSOD).
Alpha waves oscillate between 8 and 14 Hz, with the peak frequency varying between individuals. The researchers demonstrated how a measurement of an individual’s alpha wave frequency can be used as a reliable pain indicator. Also, the researchers said, these alpha waves could be used to help clinicians understand how susceptible a patient is to experience severe pain following surgery.
“Understanding a patient’s pain sensitivity could be really important in, for example, deciding whether an elective procedure is the best option or planning post-surgery rehabilitation,” said Dr. David Seminowicz of the UMSOD. “Pain management drugs or techniques such as mindfulness meditation can also be used before surgery to help minimize pain.”
“Severe pain following surgery is often also a good indicator of whether or not a patient is likely to go on to develop chronic pain. Understanding whether or not a person is at high risk of developing these symptoms will help patients and clinicians make better informed choices about the best course of treatment,” said Dr. Ali Mazaheri of the University of Birmingham’s School of Psychology and Centre for Human Brain Health.
Alpha waves are just one type of electrical activity going on continually in the brain, the researchers said. They’re thought to be most present when a person is awake, but maybe idle. In human sensory systems, their presence signals that a particular part of the system has “closed down” for processing, the researchers said. When the waves are reduced, that system is ready to start working again.
For most people, these oscillations occur continuously in the brain at frequencies of between 8 and 14 Hz. Previous studies carried out by the researchers showed that people with alpha waves occurring at the higher end of this scale were more resilient to pain, while those at the lower end were more susceptible.
In their latest study, the researchers wanted to find out whether, by taking an initial measurement of the subject’s alpha waves, it was possible to predict their reaction to pain. The researchers tested 61 healthy subjects, both men and women, aged 21 to 41.
Alpha waves were measured in each subject using electroencephalography, and each subject was exposed to two different pain episodes. In the first, a cream including capsaicin, which is the active ingredient in chili peppers, was applied to produce sensitized skin. In the second, participants underwent repeated applications of heat. After eight weeks, the subjects returned to repeat the experiment.
The results showed that measuring alpha waves did produce a reliable indication of a person’s susceptibility or resilience to pain, the researchers said. These results were reliable both in the initial assessment and in the eight-week follow-up, they added.
In Birmingham, these principles already are being tested in partnership with clinicians at the Heartlands and Queen Elizabeth Hospitals. Mazaheri is leading a study investigating the use of alpha waves and the pain experience of lung cancer patients undergoing lung biopsies.
“We know that lung surgery is a particularly painful procedure, with between 40% and 60% of patients going on to develop debilitating pain after surgery,” said Mazaheri. “By predicting which patients are likely to develop this pain, we can start to explore other options, such as radiotherapy, or make sure that intensive rehabilitation programs are in place to support those patients through recovery.”
The researchers are now actively seeking funding to continue this work.
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