Table 4.
Algorithm for preclinical Alzheimer's disease diagnosis.
| Approach | Preclinical AD biomarkers | Preclinical AD diagnosis |
|---|---|---|
| Pre-symptomatic genetic risk factors of familial AD | Familial AD genes: APP, PSEN1, PSEN2 | Definite preclinical AD |
| Combination of sporadic AD risk factor genes (APOE4), CSF biomarkers, and neuroimaging biomarkers | APOE4, TOMM40: Yes CSF: low Aβ42, high tau and p-tau Neuroimaging: high Aβ by PET, neurodegeneration by low 18FDG-PET |
Highly probable preclinical AD |
| Combination of sporadic AD risk factor genes (APOE4), CSF biomarkers, and neuroimaging biomarkers | APOE4: No CSF: low Aβ42, high tau and p-tau Neuroimaging: high Aβ by PET, neurodegeneration by low 18FDG-PET |
Probable preclinical AD |
| Combination of sporadic AD risk factor genes from Alzgen data base, CSF biomarkers, and neuroimaging biomarkers | Susceptible gene: Alzgene database CSF: low Aβ42, high tau and p-tau Neuroimaging: high Aβ by PET, neurodegeneration by low 18FDG-PET, deposition of tau in cortical region by 18F-T807-PET |
Probable preclinical AD |
| Combination of sporadic AD risk factor genes (APOE4), CSF biomarkers, and neuroimaging biomarkers | APOE4: No CSF: low Aβ42, high tau and p-tau Neuroimaging: high Aβ by PET, no neurodegeneration by 18FDG-PET, deposition of tau in cortical region by 18F-T807-PET |
Suspected preclinical AD |
| Combination of sporadic AD risk factor genes (APOE4), CSF biomarkers, and neuroimaging biomarkers | APOE4: No CSF: no Aβ42, high tau and p-tau Neuroimaging: low or no Aβ by PET, neurodegeneration by low 18FDG-PET |
Suspected preclinical non-AD pathophysiology |
Alzgene (http://www.alzgene.org/); Aβ, amyloid beta; APOE, apolipoprotein; CSF, cerebrospinal fluid; FDG, fluoro-2-deoxy-D-glucose; 18F-T807-PET, Fluorinated tau PET ligand; PET, positron emission tomography; TOMM40, translocate of outer mitochondrial membrane 40.