The functional connectivity of basal forebrain is associated with superior memory performance in older adults: a case-control study.

BACKGROUND: Aging is related with memory deterioration. However, some older adults demonstrate superior performance compared to age- and education-matched adults, who are referred to as superagers. To explore the neural mechanisms that mediate their unusually successful memory is important not only for the ameliorate the effects of aging in brain, but also for the prevention of neurodegenerative diseases, including Alzheimer's disease. This case-control study is aimed to investigate the effects of volume and function of basal forebrain cholinergic neurons on the cognition of superagers. METHODS: The morphometric and resting-state functional MRI analysis, including 34 superagers and 48 typical older adults, were conducted. We compared the basal forebrain gray matter density and related resting-state functional connectivity (FC) in the two groups. To investigate the relationship of FC with cognition, we measure the correlation of significant altered FC and individual cognitive domain. RESULTS: No significant differences of gray matter density was observed between superagers and typical older adults. The superagers had stronger cortical FC of Ch1-3 with left putamen and insular cortex. The strength of FC positively correlated with global cognition, memory and executive function. CONCLUSIONS: These findings demonstrated that the stronger FC of basal forebrain correlated with specific cognitive difference in global cognition and domains of memory and executive function in superagers.

N6-methyladenine-modified DNA was decreased in Alzheimer's disease patients.

BACKGROUND: In recent years, the prevalence of Alzheimer's disease (AD) has increased, which places a great burden on society and families and creates considerable challenges for medical services. N6-methyladenine (m6A) deoxyribonucleic acid (DNA) adenine methylation is a novel biomarker and is abundant in the brain, but less common in AD. We support to analyze the relationship between DNA m6A and cognition in patients with AD and normal controls (NCs) in China. AIM: To analyze the relationship between the novel m6A DNA and cognition in patients with AD and NCs in China. METHODS: A total of 179 AD patients (mean age 71.60 ± 9.89 years; males: 91; females: 88) and 147 NCs (mean age 69.59 ± 11.22 years; males: 77; females: 70) who were age- and sex-matched were included in our study. All subjects underwent neuropsychological scale assessment and magnetic resonance imaging examination. Apolipoprotein E (APOE) genotypes were measured through agarose gel electrophoresis. Global m6A levels were evaluated by a MethylFlash m6A DNA Methylation ELISA Kit (colorimetric). Global m6A levels in total DNA from ten AD patients with 18F-AV-45 (florbetapir) positron emission tomography (PET) positivity and ten NCs with PET negativity were analyzed by dot blotting to determine the results. RESULTS: Our ELISA results showed that the global m6A DNA levels in peripheral blood were different between patients with AD and NCs (P = 0.002; < 0.05). And ten AD patients who were PET positive and ten NCs who were PET negative also showed the same results through dot blotting. There were significant differences between the two groups, which indicated that the leukocyte m6A DNA levels were different (P = 0.005; < 0.05). The m6A level was approximately 8.33% lower in AD patients than in NCs (mean 0.011 ± 0.006 vs 0.012 ± 0.005). A significant correlation was found between the Montreal Cognitive Assessment score and the peripheral blood m6A level in the tested population (r = 0.143, P = 0.01; < 0.05). However, no relationship was found with APOE ε4 (P = 0.633, > 0.05). Further studies should be performed to validate these findings. CONCLUSION: Our results show that reduced global m6A DNA methylation levels are significantly lower in AD patients than in NCs by approximately 8.33% in China.

[Characteristics and influencing factors of non-motor symptoms in Parkinson's disease].

OBJECTIVE: To assess the characteristics and influencing factors of non-motor symptoms (NMS) in patients with Parkinson's disease (PD). METHODS: A total of 111 patients with PD and 46 healthy controls (HC) matched with age, gender, education status and occupation were investigated by NMS questionnaire. They were all outpatients of Beijing hospital. The distribution of NMS items was analyzed between two groups. And their clinical characteristics were also collected to assess the dominant influencing factors for the prevalence of NMS. RESULTS: There was significant difference in the prevalence of NMS between two groups (P < 0.01). Each PD patient had an average of 12 NMS throughout the disease stages and the number of NMS was increasing with the degree of disease severity. UPDRS-III (united Parkinson's disease rating scale), daily dose of levodopa and age showed a positive correlation with NMS-T (NMS Total) and they accounted for 26.9% of the variance of NMS-T. Daily dose of levodopa, Hoehn-Yahr stage, UPDRS-III and NMS-T showed a positive correlation with UPDRS-II and they accounted for 70.3% variance of UPDRS-II. CONCLUSION: NMS are more commonly seen in PD patients than in controls. NMS is present throughout every stages of PD and its number increases with the degree of disease severity and age. The quality of life is impaired significantly by NMS in PD patients.

Impairment in the Intention Formation and Execution Phases of Prospective Memory in Parkinson's Disease.

Objective: Patients with Parkinson's disease have prospective memory impairments. However, little is known about distinct phases of prospective memory in these patients. This study was designed to elucidate the specific phase(s) of prospective memory that are impaired in patients with Parkinson's disease. Methods: The study included 31 Parkinson's disease patients and 27 healthy controls. The four phases of prospective memory (intention formation, retention, initiation, and execution) were examined in a complex prospective memory task. In this task, the participants were asked to form a sophisticated plan for performing six subtasks to obtain the highest score, and then execute the plan following a cue embedded in a questionnaire. Global cognitive function and relevant cognitive abilities, including attention, short-term memory, working memory, and inhibition, were also evaluated during the retention phase of the prospective memory task. Results: Intention formation was impaired in Parkinson's disease patients (p < 0.001 vs. healthy controls). This impairment could not be attributed to deficits in other cognitive functions. The score of intention execution was also lower in Parkinson's disease patients (p = 0.004 vs. healthy controls). Such a difference was related to working memory deficits in Parkinson's disease. The intention retention and initiation were intact in Parkinson's disease patients. The score of intention execution correlated negatively with disease severity and disease duration. Conclusions: Prospective memory in Parkinson's disease patients is impaired at the phase of intention formation. The worsening performance of intention execution in Parkinson's disease may be related to working memory deficits. In addition, prospective memory impairment might progress with increasing disease duration and severity.