Microstructural brain changes track cognitive decline in mild cognitive impairment

Emilie T. Reas; Donald J. Hagler, Jr; Nathan S. White; Joshua M. Kuperman; Hauke Bartsch; Christina E. Wierenga; Douglas Galasko; James B. Brewer; Anders M. Dale; Linda K. McEvoy

NeuroImage: Clinical (Jan 2018)

Microstructural brain changes track cognitive decline in mild cognitive impairment

Emilie T. Reas,
Donald J. Hagler, Jr,
Nathan S. White,
Joshua M. Kuperman,
Hauke Bartsch,
Christina E. Wierenga,
Douglas Galasko,
James B. Brewer,
Anders M. Dale,
Linda K. McEvoy

Affiliations

Emilie T. Reas: Department of Neurosciences, University of California, San Diego, La Jolla, CA, USA; Center for Multimodal Imaging and Genetics, University of California, San Diego, La Jolla, CA, USA; Corresponding author at: Center for Multimodal Imaging and Genetics (CMIG), 9500 Gilman Dr., Mail Code 0841, La Jolla, CA 92093-0841, USA
Donald J. Hagler, Jr: Center for Multimodal Imaging and Genetics, University of California, San Diego, La Jolla, CA, USA; Department of Radiology, University of California, San Diego, La Jolla, CA, USA
Nathan S. White: Center for Multimodal Imaging and Genetics, University of California, San Diego, La Jolla, CA, USA; Department of Radiology, University of California, San Diego, La Jolla, CA, USA
Joshua M. Kuperman: Center for Multimodal Imaging and Genetics, University of California, San Diego, La Jolla, CA, USA; Department of Radiology, University of California, San Diego, La Jolla, CA, USA
Hauke Bartsch: Center for Multimodal Imaging and Genetics, University of California, San Diego, La Jolla, CA, USA
Christina E. Wierenga: Department of Psychiatry, University of California, San Diego, La Jolla, CA, USA; Department of Veterans Affairs, San Diego Healthcare system, La Jolla, CA, USA
Douglas Galasko: Department of Radiology, University of California, San Diego, La Jolla, CA, USA
James B. Brewer: Department of Neurosciences, University of California, San Diego, La Jolla, CA, USA; Department of Radiology, University of California, San Diego, La Jolla, CA, USA
Anders M. Dale: Department of Neurosciences, University of California, San Diego, La Jolla, CA, USA; Center for Multimodal Imaging and Genetics, University of California, San Diego, La Jolla, CA, USA; Department of Radiology, University of California, San Diego, La Jolla, CA, USA
Linda K. McEvoy: Center for Multimodal Imaging and Genetics, University of California, San Diego, La Jolla, CA, USA; Department of Radiology, University of California, San Diego, La Jolla, CA, USA; Department of Family Medicine and Public Health, University of California, San Diego, La Jolla, CA, USA

Journal volume & issue: Vol. 20
pp. 883 – 891

Abstract

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Improved characterization of the microstructural brain changes occurring in the early stages of Alzheimer's disease may permit more timely disease detection. This study examined how longitudinal change in brain microstructure relates to cognitive decline in aging and prodromal Alzheimer's disease. At baseline and two-year follow-up, 29 healthy controls and 21 individuals with mild cognitive impairment or mild Alzheimer's disease underwent neuropsychological evaluation and restriction spectrum imaging (RSI). Microstructural change in the hippocampus, entorhinal cortex, and white matter tracts previously shown to be vulnerable to Alzheimer's disease, was compared between healthy controls and impaired participants. Partial correlations and stepwise linear regressions examined whether baseline RSI metrics predicted subsequent cognitive decline, or change in RSI metrics correlated with cognitive change. In medial temporal gray and white matter, restricted isotropic diffusion and crossing fibers were lower, and free water diffusion was higher, in impaired participants. Restricted isotropic diffusion in the hippocampus declined more rapidly for cognitively impaired participants. Baseline hippocampal restricted isotropic diffusion predicted cognitive decline, and change in hippocampal and entorhinal restricted isotropic diffusion correlated with cognitive decline. Within controls, changes in white matter restricted oriented diffusion and crossing fibers correlated with memory decline. In contrast, there were no correlations between rates of cortical atrophy and cognitive decline in the full sample or within controls. Changes in medial temporal lobe microarchitecture were associated with cognitive decline in prodromal Alzheimer's disease, and these changes were distinct from microstructural changes in normal cognitive aging. RSI metrics of brain microstructure may hold value for predicting cognitive decline in aging and for monitoring the course of Alzheimer's disease. Keywords: MRI, Diffusion imaging, Alzheimer's disease, Memory, Aging, Mild cognitive impairment, Cognitive decline

Published in NeuroImage: Clinical

ISSN: 2213-1582 (Online)
Publisher: Elsevier
Country of publisher: Netherlands
LCC subjects: Medicine: Medicine (General): Computer applications to medicine. Medical informatics; Medicine: Internal medicine: Neurosciences. Biological psychiatry. Neuropsychiatry: Neurology. Diseases of the nervous system
Website: http://www.journals.elsevier.com/neuroimage-clinical/

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