Abstract
Alzheimer’s disease (AD), which most commonly occurs in the elder, is a chronic neurodegenerative disease with no agreed drugs or treatment protocols at present. Amnestic mild cognitive impairment (aMCI), earlier than AD onset and later than subjective cognitive decline (SCD) onset, has a serious probability of converting into AD. The SCD, which can last for decades, subjectively complains of decline impairment in memory. Distinct altered patterns of default mode network (DMN) subnetworks connected to the whole brain are perceived as prominent hallmarks of the early stages of AD. Nevertheless, the aberrant phase position connectivity (PPC) connected to the whole brain in DMN subnetworks remains unknown. Here, we hypothesized that there exist distinct variations of PPC in DMN subnetworks connected to the whole brain for patients with SCD and aMCI, which might be acted as discriminatory neuroimaging biomarkers. We recruited 27 healthy controls (HC), 20 SCD and 28 aMCI subjects, respectively, to explore aberrant patterns of PPC in DMN subnetworks connected to the whole brain. In anterior DMN (aDMN), SCD group exhibited aberrant PPC in the regions of right superior cerebellum lobule (SCL), right superior frontal gyrus of medial part (SFGMP), and left fusiform gyrus (FG) in comparison of HC group, by contrast, no prominent difference was found in aMCI group. It is important to note that aMCI group showed increased PPC in the right SFGMP in comparison with SCD group. For posterior DMN (pDMN), SCD group showed decreased PPC in the left superior parietal lobule (SPL) and right superior frontal gyrus (SFG) compared to HC group. It is noteworthy that aMCI group showed decreased PPC in the left middle frontal gyrus of orbital part (MFGOP) and right SFG compared to HC group, yet increased PPC was found in the left superior temporal gyrus of temporal pole (STGTP). Additionally, aMCI group exhibited decreased PPC in the left MFGOP compared to SCD group. Collectively, our results have shown that the aberrant regions of PPC observed in DMN are related to cognitive function, and it might also be served as impressible neuroimaging biomarkers for timely intervention before AD occurs.
Highlights
Alzheimer’s disease (AD), which occurs more commonly in the elder, is a chronic neurodegenerative disease of impaired cognitive and memory (Ren et al, 2019; Wessels et al, 2019)
The studies we have performed indicated that eight prominent clusters, comprising of right superior cerebellum lobule (SCL), right rectus (REC), left fusiform gyrus (FG), left inferior frontal gyrus of triangular part (IFGTP), left middle temporal gyrus (MTG), right middle frontal gyrus (MFG), left MFG and right superior frontal gyrus of medial part (SFGMP), were revealed according to one-way ANOVA analysis
Patients with Subjective cognitive decline (SCD) exhibited aberrant phase position connectivity (PPC) in the clusters of right SCL, right SFGMP and left FG as compared with healthy controls (HC) group, by contrast, no significant difference was found in patients with Amnestic mild cognitive impairment (aMCI) resulted from two-sample T-test
Summary
Alzheimer’s disease (AD), which occurs more commonly in the elder, is a chronic neurodegenerative disease of impaired cognitive and memory (Ren et al, 2019; Wessels et al, 2019). There are no agreed drugs or treatment protocols for patients with AD. The timely detection and treatment of the early stages of AD is an urgent and realistic issue, which can improve symptoms of illness and alleviate the progression of the disease (Yang et al, 2019). Amnestic mild cognitive impairment (aMCI), as the phase close to AD, has a 10–15% probability of converting into AD per annum (Yang et al, 2017). From the above, we aim to adopt aMCI and SCD phases which may evolve into AD to explore the neural mechanism of the early stage of AD
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