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P2‐340: Diffusion Tensor Imaging Study in the Detection of White Matter Degeneration in Subjective Cognitive Decline
Author(s) -
Li Xuanyu,
Liu Zhenyu,
Tang Zhenchao,
Han Ying
Publication year - 2016
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1016/j.jalz.2016.06.1470
Subject(s) - fractional anisotropy , diffusion mri , white matter , cognitive decline , audiology , cognitive impairment , biomarker , psychology , cognition , medicine , oncology , disease , pathology , cardiology , neuroscience , magnetic resonance imaging , dementia , radiology , biochemistry , chemistry
Background: Subjective cognitive decline (SCD) refers to the selfexperiencedworsening of the cognitive capacity in elderlies,who still perform within normal range on standardized neuropsychological tests (Jessen et al., 2014). Abnormal functional connectivity within default mode network (DMN), which is important for many higher cognitive functions such as episodicmemory and self-referential process, has been observed inSCDbyusing the resting state fMRI.DMN can be further segregated into several sub-networks. It is unclear, whether the functional connectivity within these sub-networks is impaired in the SCD subjects. Methods: 17 SCD subjects and 28 healthy controls (HC) underwent the standardized neuropsychological tests and the resting state fMRImeasurements. The preprocessing of the fMRI images was accomplished by SPM12 by using standard procedure including DARTEL normalization and field map correction. Then, the decomposed independent components (ICs) corresponding to all interested DMN sub-networks of a particular subject were extracted by using a spatial constrained independent component analysis (ICA) with the predefined spatial references of the DMN sub-networks. Group differences between the SCD and HC subjects in each individual IC were carried out by using the two-sample t tests implemented in SPM12. Results: Both groups were not different in the demographic data and neuropsychological performance. Using the spatial constrained ICA technique, three independent components of DMN subnetworks were extracted for each subject, including the midline core network, the dorsal medial prefrontal subnetwork, and the medial temporal lobe subnetwork. Compared to the HC group, the SCD group showed decreased functional connectivity between the dorsal medial prefrontal subnetwork and the right hippocampus, but an increased functional connectivity between themidline core network and the superiormedial frontal cortex (pFWE<0.05; Figure 1). Conclusions: The finding of decreased functional connectivity within the DMN in the right hippocampus in SCD subjects is consistent with a previous resting state functional connectivity study, andmay indicate subtle disruption of the episodic memory system. SCD subjects showed increased connectivity between the midline core subsystem of DMN network and the superior medial frontal cortex,which is a componentof the self-referential system. This result may correspond to self-awareness of cognitive deficits in the SCD subjects.