Table 1.

Sample characteristics

	Group				p-value

	HCS (N = 21)		aMCI (N = 15)

	Mean	SD	Mean	SD
Age (y)	70.5	4.0	74.2	9.6	0.14
Gender (male, n)	14		11		0.67^a
Education (y)	14.7	3.1	14.8	4.0	0.78
MMSE score (/30)	29.7	0.6	28.6	1.2	0.001
APOE ε4 carrier (n)	4		5		0.33^a
PiB(+) status (n)	5		7		0.11^a
Local PiB retention (in PCC)	1.3	0.38	1.6	0.7	0.61
Global cortical PiB retention	1.2	0.21	1.5	0.4	0.12

Diagnostic groups did not differ for age, gender, education, APOE carrier status, PiB status, or local and global PiB uptake ratios but for MMSE score. PiB uptake ratios were calculated by dividing uptake in the posterior cingulate cortex (local) and the entire cerebral cortex (global cortical) by cerebellar PiB uptake as a reference. Group comparisons were either performed by Mann-Whitney U test or χ² statistics depending on the scale of measure. Significant p-values are indicated in bold letters (p < 0.05).

Key: aMCI, amnestic mild cognitive impairment; APOE, apolipoprotein E; HCS, healthy control subjects; MMSE, Mini Mental State Examination; PCC, posterior cingulate cortex; PiB, Pittsburg compound B; SD, standard deviation.

Indicates χ².