Intermittent vibrations attenuate fluctuations in pressure pain (2014)

Undergraduate: Nathan Ahlgrim

Faculty Advisor: Mark Hollins
Department: Psychology & Neuroscience

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The effects of chronic pain are debilitating and long-lasting, which make traditional tools like pharmaceuticals impractical and ineffective. One alternative treatment is vibratory stimulation to promote pain gating ¿ decreased pain in the presence of innocuous tactile stimuli. However, evidence concerning the parameters to maximize pain modulation is contradictory. Earlier work has shown that vibration can even increase pain in those who sensitize rapidly to repetitive heat stimuli, suggesting that the application of vibration to increasing pain can exacerbate the change (Hollins, Harper & Maixner, 2011). The present study changed the force of a pressure stimulus to elicit large changes in pain and selectively applied vibration while subjects reported their pain as increasing or decreasing. Although the vibration condition did not cause a change in overall pain, the presence of vibration attenuated the pain fluctuations. A similar phenomenon was found when runs were grouped by order: earlier runs created smaller increases and decreases of pain. These findings suggest that offset analgesia is related to vibratory pain gating and sensitization. The lack of difference in pain between vibration paradigms suggests that vibratory hyperalgesia is a result of a central process unrelated to changes in pain intensity. Nevertheless, the change in fluctuations found with vibration and sensitization may provide a new parameter for effective vibratory pain modulation.