Image: A new study suggests measuring brain wave frequency can indicate pain predilection (Photo courtesy of 123rf).
The frequency of alpha brain waves can be used as a measure of an individual’s vulnerability to developing and experiencing pain, according to a new study.
Researchers at the University of Maryland Medical Center (UMM; Baltimore, USA) and the University of Birmingham (UB; United Kingdom) conducted a study in 21 volunteer subjects in order to investigate the relationship between the peak frequency of alpha brain wave activity and sensorimotor cortex and pain intensity, as manifested by electroencephalography (EEG). For the study, the researchers used the capsaicin-heat pain (C-HP) pain model, which is known to induce spinal central sensitization in primates.
All participants were induced into a state of prolonged pain for about an hour using capsaicin paste--an ingredient found in hot chili peppers--rubbed into their left forearm and heated, resulting in thermal hyperalgesia, a common symptom in chronic pain. EEG recordings revealed that those who had a slower frequency of alpha brain waves before the pain reported being in much more pain than those who had a faster frequency of alpha brain waves; and if alpha frequency increased during the experience of pain, the subjects reported to be in less pain than when alpha pain decreased. The study was published on February 28, 2018, in Neuroimage.
“What was very surprising was that prior to the pain…alpha frequency could predict how much pain individuals would experience,” said lead author Andrew Furman, MD, of the UMM department of neural and pain sciences. “This would suggest that it could be that the slowing of alpha activity in the chronic pain patients isn't because of the pain, but rather these individuals had slow alpha frequency to begin with, and as such were more prone or vulnerable to developing pain.”
Brainwaves are produced by synchronized electrical pulses from masses of neurons communicating with each other, with speed measured in Hertz. Infra-Low brainwaves are thought to be basic cortical rhythms that underlie higher brain functions; Delta waves are slow, loud brainwaves generated in deepest meditation and dreamless sleep; Theta brainwaves occur most often in sleep, but are also dominant in deep meditation; Alpha brainwaves are the resting state for the brain; Beta brainwaves dominate the normal waking state of consciousness; and Gamma brainwaves are thought to modulate perception and consciousness.
University of Maryland Medical Center
University of Birmingham