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
