ABNORMAL BRAIN STRUCTURAL AND FUNCTIONAL NETWORKS IN ELDERLY FEMALE PATIENTS WITH MILD COGNITIVE IMPAIRMENT

Abstract Background Mild cognitive impairment (MCI) is a transitional state between normal aging and Alzheimer's Disease (AD). As characterized by memory loss, amnestic MCI(aMCI) has a higher risk of developing into AD and is the target population for early diagnosis of AD. However, female aMCI patients have a faster cognitive decline and are more likely to develop AD. Aims & Objectives We analyzed the brain functional and structural network topological properties of elderly women with mild cognitive impairment for the first time, aiming to find the changes of brain network in female aMCI population and provide neuroimaging evidence for early non-invasive accurate diagnosis and treatment of female aMCI population. Method 38 elderly women with aMCI and 37 age-matched Healthy controls (HC) were recruited. Inclusion criteria: female; 60-79 years old; Geriatric Depression Scale-30 items(GDS-30) score no more than 15, Activities of Daily Living (ADL) with a cutoff score <23, no dementia. The aMCI group also met Peterson aMCI research diagnostic criteria. A battery of neuropsychological assessments and magnetic resonance imaging data were collected for both groups. Brain functional and structural networks were constructed to calculate the corresponding global and local topological property indexes of the network. With years of education as a covariate, two-sample t test was used to compare the differences in general demographic data, cognitive function scores and network topological attributes between the two groups. Results For global topological properties, no significant difference was found in the clustering coefficient (Cp), shortest path length (Lp), small world coefficient (Sigma), global network efficiency (Eg) and local network efficiency (Eloc) between groups(P >0.05). For local topological properties of brain functional network, aMCI group showed decreased betweenness centrality (Bc) in the left angular gyrus of the inferior parietal margin and the left supramarginal gyrus, increased degree centrality (Dc) in the left cuneus. On the left orbital superior frontal gyrus, left middle occipital gyrus and left precuneus, node clustering coefficient (NCp) and node local efficiency (NLe) were increased in aMCI group. However,on the right orbital inferior frontal gyrus, NCp and NLe were decreased compared with the HC group. As to local topological properties of brain structural network, the aMCI group showed increased Dc, node efficiency (Ne) and decreased node shortest path length (NLp) in the right superior parietal gyrus and left paracentral lobule compared with the HC group. On the right pallidum, aMCI group showed significantly decrease in Bc, Ne and increased in NLp. Besides, aMCI group showed increased Bc on bilateral orbital superior frontal gyrus and left middle occipital gyrus, and decreased Bc of right insula. Discussion & Conclusion No statistically significant changes were found in global topological properties of brain functional and structural network in elderly female patients with aMCI. While the local topological properties change in the superior frontal gyrus, middle occipital gyrus and cuneus. These abnormal changes may provide neuroimaging evidence for the early diagnosis of cognitive decline in elderly women.