Table 1.
Comparison of Qualitative Study Design Characteristics for All Existing Twin Reports Using MRI in Typically Developing Populations
| Study | Population | Substructures measured? |
Morphological measures? |
Voxel-level measures? |
Brain and behavior? |
Multivariate analyses? |
SEM-based statistics? |
Longitudinal design? |
|---|---|---|---|---|---|---|---|---|
| Reveley, 1984 | Adult | Y2 | N | N | N | N | Y | N |
| Oppenheim, 1989 | Adult | Y2 | Y2 | N | N | N | N | N |
| Steinmetz, 1994 | Adult | N | Y | N | N | N | N | N |
| Steinmetz, 1995 | Adult | Y | N | N | Y7 | N | N | N |
| Bartley, 1997 | Adult | Y | Y | N | N | N | Y | N |
| Biondi, 1998 | Adult | Y | Y | N | N | N | N | N |
| Bonan, 1998 | Adult | Y | Y | N | N | N | N | N |
| Carmelli 1998 | Adult | N | N | N | N | N | Y | N |
| Haidekker, 1998 | Adult | N | Y | N | N | N | N | N |
| Tramo, 1998 | Adult | Y | N | N | Y | N | N | N |
| Carmelli, 1999 | Adult | N | N | N | Y | N | N | N |
| Lohman, 1999 | Adult | N | Y | N | N | N6 | N | N |
| Le Goualher, 2000 | Adult | N | Y | N | N | N | N | N |
| Pennington, 2000 | Pediatric1 | Y | N | N | Y | Y | N | N |
| Pfefferbaum, 2000 | Adult | Y2 | N | N | N | Y3 | Y | N |
| Posthuma 2000 | Adult | N | N | N | N | Y | Y | N |
| Barré, 2001 | Adult | N | N | N | N | Y | Y | N |
| Pfefferbaum, 2001 | Adult | Y2 | N | N | N | N | Y | N |
| Sullivan, 2001 | Adult | Y | N | N | N | N | Y | N |
| Thompson, 2001 | Adult | N | N | Y | Y | N | N | N |
| Carmelli 2002a | Adult | Y | N | N | Y | N | Y | N |
| Carmelli 2002b | Adult | N5 | N | N | Y | N | Y | N |
| Eckert, 2002 | Pediatric | Y | N | N | N | N | N | N |
| Geschwind, 2002 | Adult | Y | N | N | Y7 | N | Y | N |
| Hulshoff Pol, 2002 | Adult | Y2 | N | N | N | N | Y | N |
| Posthuma 2002 | Adult | N | N | N | Y | Y | Y | N |
| Reed, 2002 | Adult | Y2 | N | N | N | N | N | N |
| White, 2002 | Adult | Y | N | N | N | N | N | N |
| Wright, 2002 | Adult | Y | N | N | N | Y3* | Y | N |
| Scamvougeras, 2003 | Adult | Y2 | N | N | N | N | N | N |
| Styner, 2003 | Adult | Y | Y | N | N | N | N | N |
| Mohr, 2004 | Adult | N | Y | N | N | N | N | N |
| Pfefferbaum, 2004 | Adult | Y2 | Y2 | N | N | Y | Y | Y4 |
| Wallace et al., 2006 | Pediatric | Y | N | N | N | N | Y | N |
| Hulshoff Pol, 2006 | Adult | Y | N | Y | Y | N | Y | N |
| Schmitt et al., 2007 | Pediatric | Y | N | N | N | Y | Y | N |
Note: ‘Substructures measured’ is an indication of whether parcellation data for ROIs are reported for structures other than total brain, intracranial volume, or hemispheric volumes. A ‘Y’ for brain and behavior is indicative that the study not only measured psychometric and imaging variables, but also attempted to describe brain-behavioral relationships. In contrast, the ‘Multivariate Analyses’ column identifies studies that model relationships between neuroanatomic variables.
Greater than 70% of the twin sample was reading disabled
Only midsagittal structures (lateral ventricles and/or corpus callosum) were measured
Bivariate, or bivariate with post-hoc principal component analysis (3*)
Two timepoints
White matter hyperintensities were the only neuroanatomic variable reported
PCA used, but to assess global, rather than structure-specific, eigenvalues
Handedness only