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. Author manuscript; available in PMC: 2017 Sep 1.
Published in final edited form as: Neurobiol Aging. 2016 Jun 6;45:169–177. doi: 10.1016/j.neurobiolaging.2016.05.023

Table 3.

Associations of Pathologic Indices and R2 with Rate of Cognitive Decline

Model Outcome (Cognitive Domain) Variable Slope Estimate SE p
Global Cognition Time (reference) −0.0527 0.0095 0.0009
Alzheimer’s Pathology −0.0544 0.0077 <0.0001
Gross Infarcts −0.0258 0.0100 0.0099
Lewy Bodies −0.0268 0.0108 0.013
Composite R2 0.053 0.0084 <0.0001
Episodic Memory Time (reference) −0.0450 0.0112 <0.0001
Alzheimer’s Pathology −0.0636 0.0091 <0.0001
Gross Infarcts −0.0299 0.0117 0.011
Lewy Bodies −0.0106 0.0127 0.40
Composite R2 0.054 0.0092 <0.0001
Semantic Memory Time (reference) −0.0390 0.0106 0.0012
Alzheimer’s Pathology −0.0629 0.0086 <0.0001
Gross Infarcts −0.0199 0.0110 0.069
Lewy Bodies −0.0117 0.0117 0.32
Composite R2(+) 0.060 0.0087 <0.0001
Composite R2(−) −0.020 0.0061 <0.0001
Working Memory Time (reference) −0.0538 0.0837 <0.0001
Alzheimer’s Pathology −0.0338 0.0073 <0.0001
Gross Infarcts −0.0258 0.0097 0.0079
Lewy Bodies −0.0145 0.0103 0.16
Composite R2 0.038 0.0069 <0.0001
Perceptual Speed Time (reference) −0.0979 0.0110 <0.0001
Alzheimer’s Pathology −0.0375 0.0087 <0.0001
Gross Infarcts −0.0149 0.0114 0.19
Lewy Bodies −0.0391 0.0121 0.0013
Composite R2 0.038 0.0079 <0.0001

For each cognitive domain, a random effects model included terms for time before death, demographic measures, all pathologic indices, and R2 variables, as well as slope terms (interactions with time). Estimated coefficients for these slope (rate-of-change) terms are shown in the table. The positive slope estimates for the R2 variables indicate that smaller values of R2 (slower transverse relaxation) are associated with more negative (faster) rates of cognitive decline, the exception being the second R2(−) variable for semantic memory. SE = standard error.