Association of Source of Memory Complaints and Increased Risk of Cognitive Impairment and Cognitive Decline： A Community-Based Study

Background： Memory complaint is common in the elderly. Recently, it was shown that self-report memory complaint was predictive of cognitive decline. This study aimed to investigate the predictive value of the source of memory complaints on the risk of cognitive impairment and cognitive decline in a community-based cohort. Methods： Data on memory complaints and cognitive function were collected among 1840 Chinese participants （aged ≥55 years old） in an urban community at baseline interview and 5-year follow-up. Incident cognitive impairment was identified based on education-adjusted Mini-Mental State Examination score. Logistic regression model was used to estimate the association between the source of memory complaints and risk of cognitive impairment conversion and cognitive decline, after adjusting for covariates. Results： A total of 1840 participants were included into this study including 1713 normal participants and 127 cognitive impairment participants in 2009. Among 1713 normal participants in 2009, 130 participants were converted to cognitive impairment alter 5 years of follow-up. In 2014, 606 participants were identified as cognitive decline. Both self- and informant-reported memory complaints were associated with an increased risk of cognitive impairment （odds ratio [OR] - 1.60, 95% confidence interval [CI]： 1.04 2.48） and cognitive decline （OR = 1.30, 95% CI： 1.01-1.68）. Furthermore, this association was more significant in males （OR = 2.10, 95% CI： 1.04-4.24 for cognitive impairment and OR - 1.87, 95% CI：1.20-2.99 for cognitive decline） and in higher education level （OR - 1.79, 95% CI： 1.02-3.15 for cognitive impairment and OR = 1.40, 95% CI：1.02-1.91 for cognitive decline）. Conclusions： Both self- and informant-reported memory complaints were associated with an increased risk of cognitive impairment conversion and cognitive decline, especially in persons with male gender and high educational background.

Aberrant functional connectivity network in subjective memory complaint individuals relates to pathological biomarkers

Background:Individuals with subjective memory complaints(SMC)feature a higher risk of cognitive decline and clinical progression of Alzheimer’s disease(AD).However,the pathological mechanism underlying SMC remains unclear.We aimed to assess the intrinsic connectivity network and its relationship with AD-related pathologies in SMC individuals.Methods:We included 44 SMC individuals and 40 normal controls who underwent both resting-state functional MRI and positron emission tomography(PET).Based on graph theory approaches,we detected local and global functional connectivity across the whole brain by using degree centrality(DC)and eigenvector centrality(EC)respectively.Additionally,we analyzed amyloid deposition and tauopathy via florbetapir-PET imaging and cerebrospinal fluid(CSF)data.The voxel-wise two-sample T-test analysis was used to examine between-group differences in the intrinsic functional network and cerebral amyloid deposition.Then,we correlated these network metrics with pathological results.Results:The SMC individuals showed higher DC in the bilateral hippocampus(HP)and left fusiform gyrus and lower DC in the inferior parietal region than controls.Across all subjects,the DC of the bilateral HP and left fusiform gyrus was positively associated with total tau and phosphorylated tau181.However,no significant between-group difference existed in EC and cerebral amyloid deposition.Conclusion:We found impaired local,but not global,intrinsic connectivity networks in SMC individuals.Given the relationships between DC value and tau level,we hypothesized that functional changes in SMC individuals might relate to pathological biomarkers.