Table 1.

Participant demographics

	Threshold derivation study		Threshold validation study
	Young adults	Older adults	Older adults
n	18	154	50
Male (%)	8 (44%)	69 (45%)	33 (66%)
Age at PET	23.7 (2.9)	76.0 (6.2)	69.8 (9.6)
Education	13.2 (6.2)	16.1 (2.5)	15.7 (2.9)
MMSE	–	28.9 (1.2)	21.6 (6.8)
ApoE4 (%)	7 (47%)a	45 (31%)b	13 (27%)c
CDR	–	–	1.2 (0.8)
Time from PET to death (years)	–	–	3.1 (1.8)
PiB index DVR	1.01 (.03)	1.12 (.20)	1.14 (.29)d
PiB+ (%), DVR cut-off 1.08	0 (0%)	57 (37%)	18 (40%)d
PiB+ (%), DVR cut-off 1.20	0 (0%)	34 (22%)	13 (29%)d
Clinical diagnosis at PET	Normal (18)	Normal (154)	FTDe (28), AD (11), MCI (7), AD/SIVD (1), DLB (1), normal (2)
Primary neuropathological diagnosis	–	–	FTLDf (25), AD (6), CVD (6), AD/CVD (3), AD/DLB (3), AD/FTLD (4), TPD (1), AGD (1), no pathological findings (1)
CERAD (absent, sparse, moderate, frequent)	–	–	18, 8, 4, 20

Shown are mean (SD) unless specified otherwise.

^aThree subjects were not genotyped.

^bEight subjects were not genotyped.

^cTwo subjects were not genotyped.

^dDVR data missing for five subjects.

^eClinical syndromes included: corticobasal syndrome (CBS; 8), behavioural-variant FTD (6), FTD and amyotrophic lateral sclerosis (5), non-fluent variant primary progressive aphasia (nfvPPA; 5), nfvPPA/CBS (1), semantic variant PPA (3).

^fFTLD neuropathological subtypes: FTLD-TDP (12), corticobasal degeneration (7), Pick’s disease (3), progressive supranuclear palsy (2), FTLD with non-specific 4-repeat tauopathy (1).

AD = Alzheimer’s disease; AGD = argyrophillic grain disease; ApoE = apolipoprotein E; CDR = Clinical Dementia Rating; CVD = cerebrovascular disease; MCI = mild cognitive impairment; DLB = dementia with Lewy bodies; FTD = frontotemporal dementia; FTLD = frontotemporal lobar degeneration; MMSE = Mini-Mental State Examination; SIVD = subcortical ischaemic vascular disease; TPD = tangle-predominant dementia.