PT - JOURNAL ARTICLE AU - Pike, Kerryn AU - Villemagne, Victor AU - Jones, Gareth AU - Ackermann, Uwe AU - O'Keefe, Graeme AU - Ames, David AU - Ellis, Kathryn AU - Masters, Colin AU - Rowe, Christopher TI - Beta-amyloid imaging and memory in a large cohort of elderly individuals DP - 2008 May 01 TA - Journal of Nuclear Medicine PG - 33P--33P VI - 49 IP - supplement 1 4099 - http://jnm.snmjournals.org/content/49/supplement_1/33P.4.short 4100 - http://jnm.snmjournals.org/content/49/supplement_1/33P.4.full SO - J Nucl Med2008 May 01; 49 AB - 132 Objectives: We previously reported a correlation between beta-amyloid burden and episodic memory in nondemented individuals but not in Alzheimer’s disease (AD). We revisited this issue using twice as many participants and a new normal range for cognitive performance that excluded apparently normal subjects with positive PiB-PET scans. Methods: 83 healthy controls (HC), 53 mild cognitive impairment (MCI), and 51 AD participants were studied. Beta-amyloid burden was quantified using PiB-PET imaging to calculate a neocortical standardized uptake value normalized to cerebellum. Composite episodic memory and nonmemory scores were calculated using 53 PiB negative healthy controls as the reference. Results: There were strong correlations between amyloid burden and both memory (r=-.66, p<.001) and nonmemory (r=-.45, p<.001) performance across all groups. When groups were analysed separately, the relationship between memory and amyloid burden remained significant in the MCI (r=-.59, p<.001) and HC groups (r=-.22, p=0.049). In contrast, there was no relationship between memory and amyloid burden in AD (r=.04). Nonmemory scores did not correlate with amyloid burden for any group. The relationship between memory and amyloid burden in nondemented individuals remained significant when PiB negative cases were removed (r=-.46, p<.001). Conclusions: The strong relationship between episodic memory impairment (the earliest cognitive change in AD) and PiB uptake in nondemented individuals supports the proposal that PiB-PET can detect AD prior to development of dementia.