Table 3.
Summary of Features and Description of Feature Sets (Note: Blocks in gray indicate the features removed for each set)
| Feature Type | Feature | Feature Description | Feature Representation | Feature Sets | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | ||||
| Demographics | Age | Age | Whether younger or older old adult | |||||||||||||
| Demographics | Gender | Gender | Whether female or male | |||||||||||||
| Demographics | Education | Level of Education | Number of years formal education was received | |||||||||||||
| Cognitive Ability | MMSE | Mini-Mental State Examination score |
Whether strong or poor cognitive ability | |||||||||||||
| Functional Imaging (rs-fMRI) | Functional Connectivity Index (FCI) | Average of Fisher transformed correlation coefficients between each pair of ROIs | Degree of functional connectivity—allowing for communication between ROIs— within network | |||||||||||||
| Structural Imaging (T1-weighted Hi-Res) | Normalized whole brain tissue volume (NWBTV) | Normalized whole brain gray and white matter volume | Degree of whole brain atrophy | |||||||||||||
| Structural Imaging (T1-weighted Hi-Res) | Normalized ROIs’ tissue volume (NRTV) | Average of normalized ROIs’ gray matter volumes | Degree of network-based regional brain atrophy | |||||||||||||
| Structural Imaging (DTI) | Mean Diffusivity (MD) | Average of all ROIs’ mean gray matter MD | Amount of diffusivity within gray matter of network | |||||||||||||
| Structural Imaging (DTI) | Number of tracks | Average of the approximate number of tracks connecting each pair of ROIs | Amount of structural connectivity—allowing for communication between ROIs— within network | |||||||||||||
| Structural Imaging (DTI) | Fractional Anisotropy (FA) | Average of all weighted mean FA computed along tracks connecting each pair of ROIs | Amount of white matter integrity within network | |||||||||||||
| Structural Imaging (T2-weighted FLAIR) | Global White Matter Hyperintensities (WMHs) | WMH burden in cerebral cortex | Amount of global (i.e. whole brain) WMH burden or white matter lesions | |||||||||||||
| Structural Imaging (T2-weighted FLAIR) | Local WMHs | Average WMH burden among tracks connecting each pair of ROIs | Amount of WMH burden or white matter lesions within network | |||||||||||||