Brain β-Amyloid and Atrophy in Individuals at Increased Risk of Cognitive Decline

Article Figures & Data

Download figure
Open in new tab
Download powerpoint
FIGURE.
Associations between increases in ¹¹C PIB uptake and reductions in GM volume in subjects with PIB+ findings at increased risk of cognitive decline. In subjects classified as positive for ¹¹C PIB uptake, significant associations are found between increases in composite ¹¹C PIB uptake and reductions in GM volume in the right temporal lobe (A and B) and increases in ¹¹C PIB uptake in the precuneus and reductions in GM volume in the left prefrontal lobe (C). D, The significant negative correlation between composite ¹¹C PIB uptake and GM volume in the right temporal lobe in the PIB+ sample (closed circles). No correlation is found in the PIB− sample (open circles). The R and P values were calculated using the average GM volumes extracted at P < .001.

Table 1:

Sample demographics and clinical characteristics^{^a}

Characteristics	All	PIB−	PIB+	PIB− vs PIB+
No. (% women)	40 (48%)	24 (50%)	16 (44%)	χ²₁ = 0.15, P = .70
Age (yr)	71 ± 5	70 ± 6	72 ± 4	t₃₈ = −1.19, P = .24
APOE ϵ4 carriers (%)	12 (31)	4 (17)	8 (53)	χ²₁ = 5.83, P = .02
Body mass index (kg/m²)	27 ± 3	28 ± 3	26 ± 2	t₃₈ = 2.14, P = .04
Systolic blood pressure (mm Hg)	137 ± 15	138 ± 15	136 ± 15	t₃₈ = 0.31, P = .76
Diastolic blood pressure (mm Hg)	81 ± 8	80 ± 8	82 ± 9	t₃₈ = −0.65, P = .52
Total serum cholesterol level (mmol/L)	5.2 ± 1	4.9 ± 1	5.5 ± 1	t₃₈ = 1.69, P = .10
Education (yr)	9 (2)	9 (2.75)	8 (2)	U = 158, P= .36
Physical activity ≥ twice per week (%)	63	52	80	χ²₁ = 3.02, P = .08
Mini-Mental State Examination	27 (2)	27 (2)	27 (3)	U = 158, P = .35
Total composite z score	0.03 ± 0.5	0.06 ± 0.6	−0.01 ± 0.5	F_1,37 = 0.018, P = .90
Memory z score	−0.05 ± 0.6	−0.10 ± 0.5	0.06 ± 0.7	F_1,37 = 2.42, P = .13
Executive function z score	0.04 ± 0.6	0.20 ± 0.6	−0.10 ± 0.4	F_1,37 = 1.94, P = .17
Processing speed z score	0.2 (0.9)	0.4 (1)	0.2 (1)	F_1,37 = 0.03, P = .86
Dementia risk score	7.5 (3.75)	8 (3.75)	7 (2)	U = 161, P = .39
Fazekas score	1 (2)	1 (2)	2 (1.75)	U = 144, P = .18

Table 2:

Summary of associations between ¹¹C PIB uptake and brain regional GM volume

¹¹C PIB Uptake Measure	Correlation with GM Volume; Region; Peak X, Y, Z Coordinates; Cluster Size; z Score; P Value
Composite	Negative correlation, right temporal lobe (29, 14, −30), 1170 mm³, z = 4.0, P = .04
Precuneus	Negative correlation, left prefrontal lobe (−38, 32, 4), 262 mm³, z = 3.8, P = .02
Prefrontal cortex	Negative correlation, right temporal lobe (29, 12, −30), 1390 mm³, z = 3.7, P = .06