Cerebral circulation - cognition and behavior最新文献

Introduction

Reduced cerebral blood flow has been associated with cognitive decline and incident dementia, with oxidative stress and reduced beta-amyloid clearance as possible mechanisms for neurodegeneration. Transcranial doppler sonography is a non-invasive tool for measuring cerebrovascular hemodynamics, including mean cerebral blood flow velocity. A systematic review and meta-analysis was performed to study mean cerebral blood flow velocity in the middle cerebral artery in persons with mild cognitive impairment and dementia compared to cognitively normal elderly.

Methods

We searched Pubmed, Embase, Cochrane Library, Epistemonikos, PsychINFO, and CINAHL according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. In total, 33439 titles and abstracts were screened, 86 articles were reviewed in full text, and 35 were included.

Results

Mean cerebral blood flow velocity in the middle cerebral artery was significantly lower in Alzheimer's disease (mean difference = 8.42; 95% confidence interval, -10.56 to -6.28), vascular dementia (mean difference = 11.75; 95% confidence interval, -14.68 to -8.82) and mild cognitive impairment (mean difference = 4.19; 95% confidence interval, -5.52 to -2.85) compared to cognitively normal elderly, see figures 1 – 3. Reduction in blood flow was equally pronounced in Alzheimer's disease and vascular dementia (mean difference = 2.79; 95% confidence interval, -0.78 to 6.35).

Discussion

Cerebral blood flow velocity is reduced in Alzheimer's disease, vascular dementia and MCI, with more pronounced disturbances in dementia.

Blood pressure variability (BPV) impacts brain health by influencing brain structure and cerebrovascular pathologies, though the mechanisms are poorly understood. Changes in the cerebrovasculature may lead to late-onset depression, cognitive impairment, and dementia, however the relationship between BPV with depression and anxiety remains unclear, due to methodological differences and inconsistencies in past research. This review aims to clarify the association between BPV with depression and anxiety in adults to inform understandings of the mechanisms implicating BPV in cognitive health. A systematic search from inception through to January 2024 was performed on Embase, PubMed, PsycINFO, and Web of Science. Studies that assessed BPV quantified by beat-to-beat, 24-hour, or visit-to-visit were eligible if the standardised assessment of depression and/or anxiety were reported as a linear association, or mean differences across control and affect groups. A total of 14 articles reporting on 13 samples and N = 5055 persons met the inclusion criteria (median female proportion = 61 %, range 0 % - 76 %). A meta-analysis was not possible due to methodological heterogeneity in BPV measurements and metrics across studies. Mixed results were observed across depression studies with inconsistencies and variation in the direction, strength of association, and BPV metric. There was weak evidence from only three studies to support a linear association between systolic coefficient of variation and anxiety. Collectively, the findings contribute to understanding the association between BPV and brain health, suggesting that any relationship between BPV and brain structures critical for cognitive function are independent of depression and only modestly implicate anxiety.