Longitudinal changes in metabolic network activity in early Alzheimer's disease

INTRODUCTIONThe progression of Alzheimer's disease (AD) has been linked to two metabolic networks, the AD-related pattern (ADRP) and the default mode network (DMN). METHODSConverting and clinically stable cognitively normal subjects (n = 47) and individuals with mild cognitive impairment (n = 96) underwent 2-[F-18]fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET) three or more times over 6 years (n(scans) = 705). Expression levels for ADRP and DMN were measured in each subject and time point, and the resulting changes were correlated with cognitive performance. The role of network expression in predicting conversion to dementia was also evaluated. RESULTSLongitudinal increases in ADRP expression were observed in converters, while age-related DMN loss was seen in converters and nonconverters. Cognitive decline correlated with increases in ADRP and declines in DMN, but conversion to dementia was predicted only by baseline ADRP levels. DISCUSSIONThe results point to the potential utility of ADRP as an imaging biomarker of AD progression.

Automated summary

The progression of Alzheimer's disease is associated with two metabolic networks, the AD-related pattern (ADRP) and the default mode network (DMN). The expression levels of ADRP and DMN were measured in individuals with mild cognitive impairment, and it was found that cognitive decline correlated with increases in ADRP and declines in DMN. Baseline ADRP levels were able to predict conversion to dementia.