TABLE 2.
Statistical comparisons of neuroimaging metrics between FTD patients versus healthy controls and post hoc comparisons among subject subgroups.
| One‐way ANOVA (omnibus test, main effect: “diagnosis”) | ||||
|---|---|---|---|---|
| Left hemisphere | Right hemisphere | |||
| F‐value (DOF), p‐value | Significant pairwise contrasts (post hoc) [p‐value] | F‐value (DOF), p‐value | Significant pairwise contrasts (post hoc) [p‐value] | |
| Cortical thickness | ||||
| Broca's area | F(6, 286) = 23.90, p < .001* |
‐ HC vs. ALSnci [p adj = .003] ‐ HC vs. ALSFTD_C9– [p adj < .001] ‐ HC vs. ALSFTD_C9+ [p adj < .001] ‐ HC vs. bvFTD [p adj < .001] ‐ HC vs. nfvPPA [p adj < .001] ‐ HC vs. svPPA [p adj = .012] ‐ ALSnci vs. ALSFTD_C9– [p adj = .023] ‐ ALSnci vs. ALSFTD_C9+ [p adj < .001] ‐ ALSnci vs. bvFTD [p adj = .032] ‐ ALSnci vs. nfvPPA [p adj < .001] |
F(6, 286) = 23.87, p < .001* |
‐ HC vs. ALSnci [p adj = .002] ‐ HC vs. ALSFTD_C9– [p adj < .001] ‐ HC vs. ALSFTD_C9+ [p adj < .001] ‐ HC vs. bvFTD [p adj < .001] ‐ HC vs. nfvPPA [p adj < .001] ‐ HC vs. svPPA [p adj = .03] ‐ ALSnci vs. ALSFTD_C9– [p adj = .014] ‐ ALSnci vs. ALSFTD_C9+ [p adj < .001] ‐ ALSnci vs. bvFTD [p adj = .010] ‐ ALSnci vs. nfvPPA [p adj < .001] |
| Wernicke's area | F(6, 286) = 13.22, p < .001* |
‐ HC vs. ALSFTD_C9– [p adj = .005] ‐ HC vs. ALSFTD_C9+ [p adj < .001] ‐ HC vs. nfvPPA [p adj < .001] ‐ ALSnci vs. ALSFTD_C9+ [p adj = .006] ‐ ALSFTD_C9– vs. nfvPPA [p adj = .035] ‐ bvFTD vs. nfvPPA [p adj = .033] |
F(6, 286) = 9.10, p < .001* |
‐ HC vs. ALSnci [p adj = .023] ‐ HC vs. ALSFTD_C9– [p adj = .010] ‐ HC vs. ALSFTD_C9+ [p adj < .001] ‐ HC vs. bvFTD [p adj = .020] ‐ HC vs. nfvPPA [p adj = .004] ‐ ALSnci vs. ALSFTD_C9+ [p adj = .007] |
| Structural connectivity: Frontal aslant tract (FAT) | ||||
| FA | F(6, 271) = 6.05, p < .001* |
‐ HC vs. ALSFTD_C9+ [p adj = .030] ‐ HC vs. nfvPPA [p adj = .012] ‐ ALSnci vs. nfvPPA [p adj = .036] |
F(6, 271) = 5.78, p < .001* |
‐ HC vs. ALSFTD_C9+ [p adj = .023] |
| RD | F(6, 271) = 12.99, p < .001* |
‐ HC vs. ALSFTD_C9– [p adj < .001] ‐ HC vs. ALSFTD_C9+ [p adj = .023] ‐ HC vs. nfvPPA [p adj < .001] ‐ ALSnci vs. ALSFTD_C9– [p adj = .017] ‐ ALSnci vs. nfvPPA [p adj = .017] ‐ nfvPPA vs. bvFTD [p adj < .001] |
F(6, 271) = 11.95, p < .001* |
‐ HC vs. ALSFTD_C9– [p adj < .001] ‐ HC vs. ALSFTD_C9+ [p adj = .011] ‐ HC vs. bvFTD [p adj = .0281] ‐ HC vs. nfvPPA [p adj < .001] ‐ ALSnci vs. ALSFTD_C9– [p adj = .016] ‐ ALSnci vs. nfvPPA [p adj = .002] |
| Structural connectivity: Arcuate fascicle (AF) | ||||
| FA | F(6, 282) = 5.50, p < .001* | ‐ HC vs. ALSFTD_C9+ [p adj = .006] | F(6, 282) = 2.38, p = .03* | – |
| RD | F(6, 271) = 21.85, p < .001* |
‐ HC vs. ALSFTD_C9– [p adj = .003] ‐ HC vs. ALSFTD_C9+ [p adj < .001] ‐ HC vs. nfvPPA [p adj < .001] ‐ HC vs. svPPA [p adj = .012] ‐ ALSnci vs. ALSFTD_C9+ [p adj = .032] ‐ ALSnci vs. nfvPPA [p adj < .001] ‐ ALSnci vs. svPPA [p adj = .001] ‐ ALSFTD_C9– vs. nfvPPA [p adj < .001] ‐ ALSFTD_C9+ vs. nfvPPA [p adj = .013] ‐ bvFTD vs. nfvPPA [p adj = .008] |
F(6, 282) = 9.89, p < .001* |
‐ HC vs. ALSFTD_C9– [p adj < .001] ‐ HC vs. ALSFTD_C9+ [p adj < .001] ‐ HC vs. nfvPPA [p adj < .001] |
| Structural connectivity: Inferior occipitofrontal fascicle (IFO) | ||||
| FA | F(6, 281) = 0.76, p = .60 | NA | F(6, 280) = 1.13, p = .35 | NA |
| RD | F(6, 281) = 9.35, p < .001* |
‐ HC vs. ALSFTD_C9– [p adj = .028] ‐ HC vs. ALSFTD_C9+ [p adj = .018] ‐ HC vs. svPPA [p adj = .003] ‐ ALSnci vs. svPPA [p adj = .026] |
F(6, 280) = 14.48, p < .001* |
‐ HC vs. ALSFTD_C9– [p adj = .001] ‐ HC vs. ALSFTD_C9+ [p adj = .005] ‐ HC vs. bvFTD [p adj = .030] ‐ HC vs. nfvPPA [p adj = .010] ‐ HC vs. svPPA [p adj = .003] ‐ ALSnci vs. svPPA [p adj = .005] |
| Structural connectivity: Inferior longitudinal fascicle (ILF) | ||||
| FA | F(6, 278) = 0.70, p = .65 | NA | F(6, 272) = 0.85, p = .53 | NA |
| RD | F(6, 278) = 9.34, p < .001* |
‐ HC vs. svPPA [p adj < .001] ‐ ALSnci vs. svPPA [p adj < .001] ‐ ALSFTD_C9– vs. svPPA [p adj < .001] ‐ ALSFTD_C9+ vs. svPPA [p adj < .001] ‐ bvFTD vs. svPPA [p adj < .001] ‐ nfvPPA vs. svPPA [p adj < .001] |
F(6, 272) = 10.76, p < .001* |
‐ HC vs. ALSFTD_C9– [p adj = .045] ‐ HC vs. nfvPPA [p adj = .046] ‐ HC vs. svPPA [p adj < .001] ‐ ALSnci vs. svPPA [p adj < .001] ‐ ALSFTD_C9– vs. svPPA [p adj = .007] ‐ ALSFTD_C9+ vs. svPPA [p adj = .012] ‐ bvFTD vs. svPPA [p adj = .031] |
| Structural connectivity: Superior longitudinal fascicle (SLF) | ||||
| FA | F(6, 282) = 8.40, p = .04* |
‐ HC vs. nfvPPA [p adj < .001] ‐ ALSnci vs. nfvPPA [p adj < .001] ‐ ALSFTD_C9– vs. nfvPPA [p adj = .002] |
F(6, 281) = 8.77, p < .001* |
‐ HC vs. ALSFTD_C9+ [p adj < .001] ‐ ALSnci vs. ALSFTD_C9+ [p adj < .001] ‐ ALSFTD_C9– vs. ALSFTD_C9+ [p adj < .001] ‐ ALSFTD_C9+ vs. bvFTD [p adj = .050] ‐ ALSFTD_C9+ vs. nfvPPA [p adj = .023] |
| RD | F(6, 282) = 2.24, p < .001* | – | F(6, 281) = 3.57, p = .002* | – |
| Structural connectivity: Uncinate fascicle (UF) | ||||
| FA | F(6, 270) = 1.08, p = .37 | NA | F(6, 273) = 3.16, p = .005* | – |
| RD | F(6, 270) = 12.02, p < .001* |
‐ HC vs. ALSFTD_C9– [p adj < .001] ‐ HC vs. nfvPPA [p adj = .029] ‐ HC vs. svPPA [p adj < .001] ‐ ALSnci vs. ALSFTD_C9– [p adj = .010] ‐ ALSnci vs. svPPA [p adj < .001] ‐ ALSFTD_C9– vs. svPPA [p adj = .041] ‐ ALSFTD_C9+ vs. svPPA [p adj = .003] ‐ bvFTD vs. svPPA [p adj = .029] |
F(6, 273) = 21.43, p < .001* |
‐ HC vs. ALSFTD_C9– [p adj < .001] ‐ HC vs. bvFTD [p adj < .001] ‐ HC vs. svPPA [p adj < .001] ‐ ALSnci vs. ALSFTD_C9– [p adj < .001] ‐ ALSnci vs. bvFTD [p adj = .006] ‐ ALSnci vs. svPPA [p adj < .001] ‐ ALSFTD_C9– vs. svPPA [p adj < .001] ‐ ALSFTD_C9+ vs. svPPA [p adj < .001] ‐ bvFTD vs. svPPA [p adj < .001] ‐ nfvPPA vs. svPPA [p adj < .001] |
| Functional connectivity | ||||
| Broca–Wernicke FC | F(6, 261) = 1.71, p = .12 | NA | F(6, 261) = 1.22, p = .30 | NA |
| Aslant tract FC | F(6, 261) = 3.41, p = .003* | ‐ HC vs. ALSnci [p adj = .001] | F(6, 261) = 1.54, p = .17 | NA |
Note: The symbol “–” represents that post hoc testing yielded no significant pairwise comparisons despite the overall significant ANOVA omnibus test.
Abbreviations: adj, adjusted; AI, artificial intelligence; ALS, amyotrophic lateral sclerosis; ALSFTDC9–(+), (non)carriers of the hexanucleotide repeat expansion in C9orf72; ALSnci, noncognitively impaired ALS; ANOVA, analysis of variance; bvFTD, behavioral variant FTD; DOF, degrees of freedom; DWI, diffusion‐weighted imaging; FA, fractional anisotropy; FC, functional connectivity; FTD, frontotemporal dementia; HC, healthy control; HSD, honest significant difference; NA, not applicable (here, ANOVA omnibus test was not significant and therefore post hoc testing was not justified); nfvPPA, nonfluent variant PPA; PPA, primary progressive aphasia; RD, radial diffusivity; rs‐fMRI, resting‐state functional magnetic resonance imaging; svPPA, semantic variant PPA; T1w, T1‐weighted.
*Significant at an alpha level of p ≤ .05.