Table 3.

Analyses with DTI White Matter Integrity as the Brain Structure Variable

C	B	A–C	A–C.B	A–B	A–B.C	B–C	B–C.A
Charlton et al. (2008), N = 118, Ages 50 to 90
Working Memory	Mean diffusivity	−.35	−.18	.77	.73	−.36	−.15
Flexibility	Mean diffusivity	−.54	−.60	.77	.79	−.39	.05
Speed	Mean diffusivity	−.55	−.53	.77	.77	−.43	−.02
Fluid Intelligence	Mean diffusivity	−.42	−.48	.77	.79	−.29	.05
Charlton et al. (2009), N = 106, Ages 50 to 90
Theory of Mind	Mean diffusivity	−.30	−.29	.78	.78	−.24	−.01
Charlton et al. (2010), N = 104, Ages 50 to 90
Episodic memory	Mean diffusivity	−.57	−.69	.78	.84	−.38	−.12
Carlesimo et al. (2010), N = 76, Ages 20 to 80
Word memory, delayed	L. Hippocampal diffusivity	−.42	−.57	.75	.79	−.23	.14
	R. Hippocampal diffusivity	−.42	−.45	.70	.71	−.27	.04
	L. Hippocampal FA	−.42	−.73	−.60	−.77	−.08	−.46
	R. Hippocampal FA	−.42	−.74	−.67	−.80	.02	−.39
Rey Visual Figure Memory	L. Hippocampal diffusivity	−.52	−.91	.75	.91	−.16	.41
	R. Hippocampal diffusivity	−.52	−.73	.70	.81	−.21	.25
	L. Hippocampal FA	−.52	−.63	−.60	−.69	.19	−.18
	R. Hippocampal FA	−.52	−.75	−.67	−.80	.16	−.30

Note: All of the B–C combinations within a given study presumably involved the same research participants. It is likely that there was at least some overlap in the samples reported in different articles by the same research team. However, the degree of overlap was not always stated, and because results were not reported separately for the new and old participants, the data were not suitable for meta-analyses.

Entries in bold represent combinations that were most consistent with the mediation model in that the reduction in A–C after control of B was larger than both the reduction of A–B after control of C and the reduction of B–C after control of A.

NA indicates that the estimates could not be computed because the relevant correlations were not available.