Table 2.

Experimental pain response following TENS, by session

		Session 1 Mean Δ (95%CI)		p	Session 2 Mean Δ (95%CI)		p	Session 3 Mean Δ (95%CI)		p	Session 4 Mean Δ (95%CI)		p
PPT	Young	0.46	(0.08,0.84)		0.34	(−0.05,0.74)		0.21	(−0.14,0.56)		0.19	(−0.19,0.57)
	Middle	0.19	(−0.19,0.57)	0.436	0.14	(−0.22,0.50)	0.362	0.08	(−0.27,0.42)	0.588	0.20	(−0.16,0.56)	0.028*
	Older	0.52	(0.14,0.90)		0.51	(0.15,0.87)		0.32	(−0.01,0.66)		0.82	(0.45,1.20)
	Total	0.39	(0.17,0.61)	0.001	0.33	(0.12,0.55)	0.003	0.20	(0.01,0.40)	0.044	0.41	(0.19,0.62)	<0.001
TS	Young	4.76	(−3.99,13.52)		−2.77	(−11.30,5.77)		0.17	(−6.80,7.14)		0.13	(−5.57,5.82)
	Middle	6.44	(−2.10,14.95)	0.571	0.32	(−7.75,8.38)	0.870	−3.35	(−3.82,10.52)	0.463	−3.74	(−8.97,1.49)	0.556
	Older	0.45	(−7.62,8.52)		−0.94	(−9.23,7.34)		−2.79	(−3.99,9.57)		0.83	(−4.54,6.21)
	Total	3.89	(−0.99,8.76)	0.116	−1.13	(−5.92,3.66)	0.638	−0.13	(−4.16,3.90)	0.948	−0.93	(−4.07,2.21)	0.427
AS	Young	−27.14	(−0.96,−53.32)		−33.12	(−6.58,−59.66)		−14.97	(0.26,−30.20)		−8.81	(7.94,−25.56)
	Middle	−29.70	(−4.86,−54.54)	0.925	−39.73	(−15.26,−64.19)	0.600	−7.08	(8.15,−22.31)	0.562	0.58	(16.88,−15.72)	0.112
	Older	−34.20	(−9.31,−58.99)		−22.35	(−4.86,−54.54)		−3.93	(18.37,−10.52)		−24.14	(−7.39,−40.88)
	Total	−30.33	(−15.73,−44.93)	<0.001	−31.73	(−17.20,−46.27)	<0.001	−8.66	(−0.02,−17.31)	0.049	−10.78	(−1.21,−20.37)	0.028

Mean Δ, mean change after TENS (95% CI of change reported in parentheses); p Age groups, significance value of age by time interaction; p Total, significance of time main effect (before and after TENS);

^*PPT change in older group only.