Preclinical stages of Alzheimer's disease have been proposed.
Parameters:
(1) dementia
(2) subtle cognitive decline, with episodic memory composite score in the lowest 10th percentile
(3) amyloid, as indicated by CSF amyloid beta(1-42) < 459 pg/mL
(4) neuronal injury, indicated by CSF t-tau > 339 pg/mL or p-tau > 67 pg/mL
Dementia |
CDR Designation |
none |
CDR 0 |
very mild |
CDR 0.5 |
mild |
CDR 1 |
moderate |
CDR 2 |
severe |
CDR 3 |
Dementia |
Subtle Cognitive Decline |
Amyloid |
Neuronal Injury |
Diagnosis |
CDR 0 |
absent |
absent |
absent |
normal |
CDR 0 |
absent |
present |
absent |
Preclinical Stage 1 |
CDR 0 |
absent |
present |
present |
Preclinical Stage 2 |
CDR 0 |
present |
present |
present |
Preclinical Stage 3 |
CDR 0 |
variable |
absent |
present |
SNAP |
CDR 0 |
present |
variable |
absent |
unclassified |
where:
• SNAP = suspected non-Alzheimer pathophysiology
The diagnosis of Alzheimer's disease involved:
(1) CDR > 0
(2) memory with score > 0.5
(3) at least one other domain with score > 0.5
(4) clinician diagnosis of Alzheimer's disease