. 2014 Feb 1;32(2):93–100. doi: 10.1089/pho.2013.3616

Table 3.

Comparison of the t30 − t0 Results Between and Within Subject Groups

	RLT (n=57)	Within-group p value	ELT (n=48)	Within-group p value	Controls (n=23)	Within-group p value	Between- group p value
Skin complexion (subjective)^a	−1.29±1.98	<0.001	−1.72±2.35	<0.001			0.064
Skin feeling (subjective)^a	−1.01±2.30	<0.001	−1.65±2.17	<0.001			0.167
Skin roughness (R_a)^a	−1.79±2.46	<0.001	−1.58±2.22	<0.001	0.95±1.45	0.003	0.003
Collagen intensity score^b	5.75±4.54	<0.001	6.40±5.17	<0.001	−0.26±5.09	0.84	<0.001
Expert wrinkle assessment^c		<0.001		<0.001		<0.001	<0.001
Better	40/69%		36/75%		1/4%
Equal	8/14%		7/15%		5/22%
Worse	10/17%		5/10%		17/74%

^{^a}

Values represent means±SD of the difference t30 − t0; negative numbers indicate improvement.

^{^b}

Values represent means±SD of the difference t30 − t0; positive numbers indicate improvement.

^{^c}

Majority vote of three blinded expert reviewers, χ² test for comparisons between groups, binomial test for within-group comparisons.

Analysis of covariance for the between-group comparison, one sample Wilcoxon-test for the within-group comparisons.

RLT, red light technology; ELT, energizing light technology.