Article Figures & Data
Figures
- Figure 1.
Relative frequency (%) of participant's baseline PIB DVR. We predefined the number of clusters to two to determine a sensitive cutoff value between low and high baseline PIB levels, which was determined based on the point where the two clusters met but did not overlap. K-means clustering analyses yielded one cluster centered at the 1.54 baseline PIB DVR (N = 10), including participants with a >1.30 PIB DVR and another cluster centered at the 1.03 baseline PIB DVR (N = 61), including participants with a <1.30 PIB DVR. The 1.30 threshold was based on this approach; the threshold for PIB positivity was 1.07, as previously reported.
- Figure 2.
Quadratic relationship between baseline PIB level and PIB slope. Participants had two (black), three (green), or four (pink) PIB PET scans. We performed linear and quadratic correlations to determine the best fit of the data.
- Figure 3.
Relationship between PIB measures and AV-1451 uptake in Braak stages I–II, III–IV, and V–VI ROIs in PIB− individuals. Participants (N = 27) were identified as PIB− (blue) and PIB+ converters (purple) based on a standard threshold of 1.07 PIB DVR. A, Correlation between baseline PIB DVR and AV-1451 uptake in Braak stages I–II in PIB− participants. B, Correlation between PIB DVR slope and AV-1451 uptake in Braak stages I–II in PIB− participants. C, Correlation between baseline PIB DVR and AV-1451 uptake in Braak stages III–IV in PIB− participants. D, Correlation between PIB DVR slope and AV-1451 uptake in Braak stages III–IV in PIB− participants. E, Correlation between baseline PIB DVR and AV-1451 uptake in Braak stages V–VI in PIB− participants. F, Correlation between PIB DVR slope and AV-1451 uptake in Braak stages V–VI in PIB− participants.
- Figure 4.
AV-1451 uptake in Braak stages I–II, III–IV, and V–VI regions. Participants were identified as PIB− (blue), PIB+ converters (purple), and PIB+ based on a standard threshold of 1.07 PIB DVR. Dotted lines in each panel indicate the threshold for classification as meeting that Braak stage. A, AV-1451 SUVR uptake in Braak stages I–II regions, with most participants being classified as stages I–II (Braak stage I/II mean SUVR, >1.129). B, AV-1451 SUVR uptake in Braak stages III–IV regions, with five participants being classified as stages III–IV (Braak stage III/IV mean SUVR, >1.304). C, AV-1451 SUVR uptake in Braak stages V–VI regions, with no participants being classified as stage V–VI (Braak stage V/VI mean SUVR, >1.873).
- Figure 5.
Relationship between PIB measures and change in episodic memory performance over time. Participants were identified as PIB− (<1.07 PIB DVR at all time points; N = 38; blue), individuals who converted to PIB+ (PIB+ converter; N = 13; purple), and those who remained PIB+ (at all time points; N = 20; red). A, Correlation between baseline PIB DVR and ΔEpisodic Memory Composite in PIB− participants (N = 51). B, Correlation between PIB DVR slope and ΔEpisodic Memory Composite in PIB− participants. C, Correlation between baseline PIB DVR and ΔEpisodic Memory Composite in PIB participants with a <1.30 baseline value (N = 61). D, Correlation between PIB DVR slope and ΔEpisodic Memory Composite in PIB participants with a <1.30 baseline value. E, Correlation between baseline PIB DVR and ΔEpisodic Memory Composite in all participants (N = 71). F, Correlation between PIB DVR slope and ΔEpisodic Memory Composite in all participants.
Tables
Variables All older adults (N = 71) <1.30 PIB older adults (N = 61) <1.07 PIB older adults (N = 51) All with AV-1451 (N = 37) <1.30 PIB with AV-1451 (N = 33) <1.07 PIB with AV-1451 (N = 27) Range PIB+ (all time points), N (%) 20 (28) 10 (16) 0 (0) 10 (27) 6 (18) 0 (0) PIB+ converters (PIB− to PIB+), N (%) 13 (18) 13 (21) 0 (0) 7 (19) 7 (21) 0 (0) PIB follow-up (years) 4.5 (2.2) 4.8 (2.4) 4.5 (2.2) 4.8 (2.4) 5.3 (2.5) 4.8 (2.4) 1.1–9.3 Cognitive testing follow-up (years) 5.7 (2.3) 6.1 (2.4) 5.9 (2.4) 5.2 (2.3) 5.6 (2.5) 5.2 (2.4) 1.8–10.8 Age (years) 75.4 (5.4) 75.1 (5.6) 75.1 (5.5) 75.5 (4.4) 75.4 (4.6) 75.6 (4.9) 61–88 Male sex, % 35 36 36 41 39 41 Years of education 17 (1.7) 17 (1.7) 17.1 (1.8) 17 (1.8) 17.2 (1.8) 17.3 (1.8) 13–20 % APOE ε4 carriers 30 22 22 32 24 22 Baseline MMSE 28.9 (1.3) 29.0 (1.2) 29.1 (1.2) 28.9 (1.4) 29.1 (1.2) 29.0 (1.3) 25–30 Baseline PIB 1.10 (0.19) 1.04 (0.07) 1.02 (0.03) 1.09 (0.17) 1.04 (0.07) 1.01 (0.03) 0.96–1.69 ΔPIB 0.02 (0.02) 0.01 (0.02) 0.008 (0.01) 0.02 (0.02) 0.01 (0.02) 0.008 (0.01) −0.009 to 0.08 ΔEpisodic Memory Composite −0.01 (0.10) −0.002 (0.09) 0.01 (0.09) 0.005 (0.10) 0.012 (0.10) 0.025 (0.11) −0.20 to 0.27 AV-1451 SUVR in Braak stages I–II 1.30 (0.21) 1.26 (0.18) 1.27 (0.19) 0.94–1.88 AV-1451 SUVR in Braak stages III–IV 1.22 (0.11) 1.20 (0.09) 1.20 (0.09) 1.03–1.48 AV-1451 SUVR in Braak stages V–VI 1.18 (0.09) 1.17 (0.09) 1.17 (0.09) 1.01–1.33 Values are given as the mean (SD), unless otherwise noted. MMSE, Mini Mental State Exam. All participants had no contradictions to MRI; were living independently in the community; scored ≥25 on the MMSE; scored within age, education, and gender norms; and had no neurological or psychiatric illness, major medical illnesses, or medications that affect cognition. All participants provided blood samples that were analyzed for APOE polymorphisms using a standard protocol. Participants were dichotomized into carriers and noncarriers of the APOE ε4 allele. AV-1451 scans were collected within 3 months of the participant's last PIB scan.
