Table 2.
Analyses with White Matter Hyperintensities (WMH) as the Brain Structure Variable
| C | B | A–C | A–C.B | A–B | A–B.C | B–C | B–C.A |
|---|---|---|---|---|---|---|---|
| Cook et al. (2002), N = 43, Ages 60 to 93 | |||||||
| Trail Making B | Peri-ventricular WMH | .57 | .53 | .47 | .42 | .33 | .09 |
| Deep WMH | .57 | .53 | .22 | .07 | .30 | .22 | |
| Shipley Abstraction | Peri-ventricular WMH | −.57 | −.53 | .47 | .42 | −.33 | −.09 |
| Deep WMH | −.57 | −.55 | .22 | .15 | −.21 | −.11 | |
| Gunning-Dixon & Raz (2003), N = 139, Ages 50 to 81 | |||||||
| Working Memory (Verbal) | Frontal WMH | −.27 | −.22 | .40 | .37 | −.22 | −.13 |
| Temporal WMH | −.27 | −.23 | .48 | .46 | −.19 | −.07 | |
| WCST (Perseverations) | Frontal WMH | .27 | .16 | .40 | .33 | .34 | .26 |
| Temporal WMH | .27 | .25 | .48 | .47 | .17 | .05 | |
| Gootjes et al. (2007), N = 36, Ages 50 to 81 | |||||||
| Dichotic listening | Deep WMH | −.59 | −.57 | .67 | .66 | −.41 | −.03 |
| Charlton et al. (2010), N = 104, Ages 50 to 93 | |||||||
| Immediate memory | WMH | −.57 | −.55 | .48 | .46 | −.30 | −.04 |
| Rabbitt et al. (2007), N = 65, Ages 64 to 85 | |||||||
| Culture Fair IQ | WMH | −.41 | −.40 | .38 | .37 | −.18 | −.03 |
| AH4-1 IQ | WMH | −.41 | −.36 | .38 | .32 | −.27 | −.14 |
| AH4-2 IQ | WMH | −.48 | −.47 | .38 | .37 | −.20 | −.02 |
| WAIS Vocabulary | WMH | −.21 | −.12 | .38 | .34 | −.28 | −.22 |
| Mill Hill A Vocabulary | WMH | −.16 | −.13 | .38 | .37 | −.13 | −.08 |
| Mill Hill B Vocabulary | WMH | −.16 | −.09 | .38 | .36 | −.21 | −.16 |
| Forward Digit Span | WMH | −.21 | −.15 | .38 | .35 | −.21 | −.14 |
| Backward Digit Span | WMH | −.19 | −.07 | .38 | .33 | −.34 | −.30 |
| Word Span | WMH | −.17 | −.09 | .38 | .35 | −.24 | −.19 |
| Memory for People | WMH | −.29 | −.20 | .38 | .32 | −.31 | −.23 |
| Memory for Objects in a Circle | WMH | −.52 | −.46 | .38 | .28 | −.34 | −.18 |
| Visual Search | WMH | −.31 | −.19 | .38 | .29 | −.38 | −.30 |
| Letter-Digit Substitution | WMH | −.33 | −.19 | .38 | .26 | −.44 | −.36 |
| Phonemic fluency | WMH | −.22 | −.16 | .38 | .35 | −.22 | −.15 |
| Category fluency | WMH | −.35 | −.24 | .38 | .28 | −.38 | −.29 |
| Brixton | WMH | .37 | .34 | .38 | .35 | .22 | .09 |
| Rey-Osterrieth Figure | WMH | −.56 | −.51 | .38 | .28 | −.33 | −.15 |
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.