Being Adaptive to Pain Enhances Sham Acupuncture Analgesia: A Crossover Healthy Human Study

Table 2 Pain sensitivity measured before each acupuncture session (mean ± SD).

Sessions	Outcome measures before acupuncture	Sites	PA (n = 9)	PNA (n = 13)	t₂₀	p-Value	Adjusted significance^#
Before real acupuncture	PPT (kPa)	Left arm	231.30 ± 81.11	189.06 ± 79.15	1.22	0.24	0.03
		Right arm	266.78 ± 82.40	198.85 ± 75.66	2.00	0.06	0.02
		Right leg	389.26 ± 150.68	347.38 ± 135.11	0.68	0.50	0.05
	SUPRA (NRS)	Left arm	6.56 ± 1.57	5.96 ± 1.38	0.94	0.36	0.03
		Right arm	6.78 ± 1.33	5.58 ± 1.59	1.86	0.08	0.02
		Right leg	6.94 ± 1.42	6.31 ± 1.69	0.92	0.37	0.05
	PIN (NRS)	Left arm	4.17 ± 1.97	3.46 ± 1.45	0.97	0.34	0.02
		Right arm	3.83 ± 2.18	3.77 ± 1.48	0.08	0.94	0.05
		Right leg	3.67 ± 2.18	3.58 ± 1.19	0.11	0.91	0.03
	Skin temperature (°C)	Point LI 10	33.58 ± 1.71	32.49 ± 1.52	1.54	0.14	0.02
		Point LI 4	31.81 ± 2.98	31.86 ± 2.71	−0.04	0.97	0.05
		Thumb	30.90 ± 4.02	29.91 ± 4.39	0.53	0.60	0.03
Before sham acupuncture	PPT (kPa)	Left arm	205.48 ± 74.02	216.51 ± 97.55	−0.29	0.78	0.02
		Right arm	236.59 ± 84.83	241.21 ± 96.81	−0.12	0.91	0.05
		Right leg	348.96 ± 142.84	361.09 ± 134.77	−0.20	0.84	0.03
	SUPRA (NRS)	Left arm	6.06 ± 1.18	6.19 ± 1.20	−0.26	0.79	0.05
		Right arm	6.67 ± 0.97	6.23 ± 1.26	0.88	0.39	0.03
		Right leg	6.89 ± 1.52	6.31 ± 1.38	0.93	0.36	0.02
	PIN (NRS)	Left arm	4.06 ± 1.91	3.35 ± 1.82	0.88	0.39	0.02
		Right arm	3.33 ± 2.00	3.62 ± 1.70	−0.36	0.73	0.03
		Right leg	3.39 ± 2.26	3.35 ± 1.77	0.05	0.96	0.05
	Skin temperature (°C)	Point LI 10	33.38 ±1.15	33.68 ± 1.45	−0.53	0.60	0.03
		Point LI 4	32.43 ± 2.25	32.65 ± 1.51	−0.28	0.79	0.05
		Thumb	32.59 ± 1.99	31.91 ± 2.73	0.64	0.53	0.02

^# Holm-Bonferroni-adjusted significance.
p values lower than the adjusted significance are considered significant; NRS = numerical rating scale 0–5–10, 0 meaning no sensation at all, 5 being just painful, and 10 the worst pain possible; PA = pain adaptive; PIN = pain rating to pinprick; PNA = pain nonadaptive; PPT = pressure pain threshold; RA = real acupuncture; SA = sham acupuncture; SD = standard deviation; SUPRA = pain rating to suprathreshold pressure stimulus.

ISSN: 3059-4049