Good vibes for the brain - Placebo versus real vibration in patients with chronic neck pain: A randomized cross-over study

Abstract

BackgroundNeck muscle vibration decreases pain and improves sensorimotor impairments in patients with chronic neck pain. However, the impact of placebo on these effects are still unclear. ObjectiveThe aim was to evaluate the effect of neck muscle vibration compared to placebo neck muscle vibration in patients with chronic neck pain. MethodsTwenty-three people with chronic neck pain participated in this double-blinded, randomized crossover study. After baseline assessment at day 1, patients received either neck muscle vibration or placebo neck muscle vibration at day 2. At day 3, patients underwent the other treatment. The primary outcomes assessed at each day were active cervical joint position sense acuity, resting pain, and pressure pain threshold. ResultsCervical joint position sense revealed a significant time effect (F1, 22 = 4.366, p = 0.016, η2 = 0.902). Post-hoc testing revealed significant increases in cervical joint position sense after neck muscle vibration (p = 0.023; d = 0.602) but not after placebo vibration. Resting pain (F1, 22 = 7.550, p = 0.003, η2 = 0.418) displayed significant time effects for neck muscle vibration and placebo vibration. Pressure pain threshold demonstrated a significant time to condition effect (F1, 22 = 6.146; p = 0.008, η2 = 0.369). Post-hoc tests revealed that only neck muscle vibration significantly increased pressure pain threshold (p = 0.043, d = 0.516). ConclusionThe study demonstrates the efficacy of neck muscle vibration to decrease neck pain and improve cervical joint position sense in patients with chronic neck pain. Nevertheless, the influence of placebo effects should not be underestimated as they may contribute to these effects, indicated by similar decreases in resting pain.