Is There a Relationship between Throbbing Pain and Arterial Pulsations?

Abstract

Pain can have a throbbing quality, especially when it is severe and disabling. It is widely held that this throbbing quality is a primary sensation of one's own arterial pulsations, arising directly from the activation of localized pain-sensory neurons by closely apposed blood vessels. We examined this presumption more closely by simultaneously recording the subjective report of the throbbing rhythm and the arterial pulse in human subjects of either sex with throbbing dental pain – a prevalent condition whose pulsatile quality is widely regarded a primary sensation. Contrary to the generally accepted view, which would predict a direct correspondence between the two, we found that the throbbing rate (44 bpm ± 3 SEM) was much slower than the arterial pulsation rate (73 bpm ± 2 SEM, p<0.001), and that the two rhythms exhibited no underlying synchrony. Moreover, the beat-to-beat variation in arterial and throbbing events observed distinct fractal properties, indicating that the physiological mechanisms underlying these rhythmic events are distinct. Confirmation of the generality of this observation in other pain conditions would support an alternative hypothesis, that the throbbing quality is not a primary sensation but rather an emergent property, or perception, whose “pacemaker” lies within the central nervous system. Future studies leading to an improved understanding of the neurobiological basis of clinically relevant pain qualities, such as throbbing, will also enhance our ability to measure and therapeutically target severe and disabling pain.

Classification, Mechanism, Biochemistry, and Genetics of Headache

“…Direct observations of this relationship were examined in a systematic way for migraine pain 14 and acute dental pain. 15 In both cases, the general psychophysical characteristic of the throbbing rhythm was too slow to be related to systole, at around 40À50 beats per minute, whereas arterial pulse in these subjects was in the usual physiological range, from 70 to 80 beats per minute. 14 Moreover, these "bedside" observations of people with migraine pain were confirmed and extended in a population of subjects with dental pain, whose simultaneous recordings of arterial pulse and psychophysical reports of their throbbing rhythm were further examined to formally exclude any possible relationship between these two rhythms.…”

“…14 Moreover, these "bedside" observations of people with migraine pain were confirmed and extended in a population of subjects with dental pain, whose simultaneous recordings of arterial pulse and psychophysical reports of their throbbing rhythm were further examined to formally exclude any possible relationship between these two rhythms. 15 A further explanation of the throbbing percept still remains to be elucidated. However, the exclusion of heart rate as a correlate of throbbing events also excludes the pulsations of cerebrospinal fluid and intracranial pressure, as these pulsations do correspond to heart rate, and the statistical properties of throbbing of both migraine and dental pain both exclude the possibility that throbbing refers to pulsations of CSF pressure.…”

Hierarchical nonlinear dynamics of human attention

“…The pulsating (throbbing) pain is typical, for example, for patients with chronic migraine (Ahn, 2012;Goadsby, 2013). In general, recent experiments indicate that the throbbing quality is not a primary sensation but rather an emergent property of neural networks within the central nervous system (Mirza et al, 2012). In fact, the dynamics of such networks reminds the dynamics of central pattern generators (see (Yuste et al, 2005)).…”

Does throbbing pain have a brain signature?

“…In fact, our recent studies of the throbbing rhythm in patients with migraine [1] and dental pain [34] formally excluded any association between the rhythm of throbbing pain and the timing of any rhythms that could be derived from hemodynamic activity, such as venous flow or cerebrospinal fluid pressure. However, we were unable to offer any evidence for an alternative source for this rhythm.…”