Abstract

PUCHE, Aura C. et al. Alteration of Entropy in the Precuneus and Posterior Cingulate Cortex in Alzheimer’s Disease: A Resting-State Functional Magnetic Resonance Study. TecnoL. [online]. 2021, vol.24, n.52, pp.136-157.  Epub Feb 22, 2022. ISSN 0123-7799.  https://doi.org/10.22430/22565337.2118.

The human brain has been described as a complex system. Its study using neurophysiological signals has revealed the presence of linear and non-linear interactions. In this context, entropy metrics have been used to discover brain behavior in the presence and absence of neurological alterations. Entropy mapping is of great interest for the study of progressive neurodegenerative diseases such as Alzheimer’s Disease (AD). The objective of this study was to characterize the dynamics of brain oscillations in AD using entropy and the Amplitude of Low-Frequency Fluctuations (ALFF) of BOLD signals from the default network and the executive control network in patients with AD and healthy individuals. For this purpose, the data was extracted from the Open Access Series of Imaging Studies (OASIS). The results revealed greater discriminatory power in Permutation Entropy (PE) than in ALFF and fractional ALFF metrics. An increase in PE was obtained in regions of the default network and the executive control network in patients. The posterior cingulate cortex and the precuneus exhibited a differential characteristic when PE was evaluated in both groups. There were no findings when the metrics were correlated with clinical scales. The results showed that PE can be used to characterize the brain function in patients with AD and reveals information about non-linear interactions complementary to the characteristics obtained by calculating the ALFF.

Keywords : Functional magnetic resonance imaging; Alzheimer’s disease; Permutation entropy; Medical image processing; Default mode network; Executive network.

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