The relationship between blood pressure and cognitive function

Studying the neuropsychological sequelae of SARS-CoV-2: lessons learned from 35 years of neuroHIV research

The virology of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) and the human immune response to the virus are under vigorous investigation. There are now several reports describing neurological symptoms in individuals who develop coronavirus disease 2019 (COVID-19), the syndrome associated with SARS-CoV-2 infection. The prevalence, incidence, and clinical course of these symptoms will become clearer in the coming months and years through epidemiological studies. However, the long-term neurological and cognitive consequence of SARS-CoV-2 infection will remain conjectural for some time and will likely require the creation of cohort studies that include uninfected individuals. Considering the early evidence for neurological involvement in COVID-19 it may prove helpful to compare SARS-CoV-2 with another endemic and neurovirulent virus, human immunodeficiency virus-1 (HIV-1), when designing such cohort studies and when making predictions about neuropsychological outcomes. In this paper, similarities and differences between SARS-CoV-2 and HIV-1 are reviewed, including routes of neuroinvasion, putative mechanisms of neurovirulence, and factors involved in possible long-term neuropsychological sequelae. Application of the knowledge gained from over three decades of neuroHIV research is discussed, with a focus on alerting researchers and clinicians to the challenges in determining the cause of neurocognitive deficits among long-term survivors.

Associations between Hypertension, Treatment, and Cognitive Function in the Irish Longitudinal Study on Ageing

Epidemiological studies have produced conflicting results regarding the associations between the use of different hypertensive drugs and cognition. Data from the Irish Longitudinal Study on Ageing (TILDA), a nationwide prospective longitudinal study of adults aged 50 or more years, was used to explore the associations between hypertensive status, categories of antihypertensive and cognitive function controlling for age, education, and other demographic and lifestyle factors. The study sample included 8173 participants. ANCOVAs and multivariate regressions were used to assess the cross-sectional and longitudinal associations between cognitive function and hypertension status and the different categories of hypertensive medication. Hypertension was not associated with decline in global cognitive and executive functions and were fully explained by age and education. Different hypertensive medications were not associated with cognitive function. Consistent with previous studies, changes in cognition can largely be explained by age and education. The use of antihypertensive medications is neither harmful nor protective for cognition.

Is there a relationship between blood pressure values and dementia?

The relationship between arterial hypertension and cognitive decline, two among the conditions with higher prevalence in the elderly population, has gained significant interest, in the scientific community, during the last few years, stemming from the numerous epidemiologic, experimental, and therapeutic evidences suggesting a non-casual correlation between the two conditions. In fact, the brain, for its substantial metabolic and functional complexity, is more susceptible to the harmful effect of high blood pressure than the other target organs. Chronic ischaemic impairment, microvascular damage, and neurodegenerative phenomena are the likely pathophysiologic basis for the correlation between hypertension and cognitive decline. Vascular dementia and Alzheimer’s disease, the two prominent forms of senile dementia, seem to represent the end result of the chronic exposure, during the lifetime, to harmful stimuli, among which the most relevant are the cardiovascular risk factors, at least from an epidemiological perspective. Evidences from interventional studies, although limited, seems to support the concept that to limit the spread of senile dementia, the early optimization of the control of cardiovascular risk factors, first and foremost hypertension, is crucial. The occurrence of a variable degree of mental decline, till overt dementia, in the hypertensive patient, represents the final step of a pathophysiologic process that began many years before. There is, then, the clear opportunity to control the pathophysiologic mechanisms leading to cognitive decline in the hypertensive patient.

The association between allostatic load and cognitive function: A systematic and meta-analytic review

Previous research suggests that high allostatic load (AL), a biological indicator of physiological dysregulation due to chronic stress, is associated with poor cognitive functioning. To date, no studies have systematically reviewed the literature to evaluate the strength and consistency of this relationship. The objective of this study was to conduct a systematic and meta-analytic review of studies that have investigated the association between AL and performance on standardized cognitive tests among adults aged 18 years and older. A total of 18 studies were retained for review. Meta-analyses revealed a significant cross-sectional association between higher AL and poor global cognition (r = -0.08, p <  0.001) and executive function (r = -0.07, p =  0.02), but not memory (r = -0.07, p =  0.10). Due to variation in statistical methods used, longitudinal meta-analyses were not performed. Qualitative review of the literature suggests that AL algorithm, physiological systems and individual biomarkers included in the AL index, and sample age may be key moderators of the AL-cognition relationship. Although the magnitude of reported associations is small, findings support AL as a robust indicator of cognitive function among adults. Study limitations and future directions are discussed.

Post-traumatic stress disorder: A differential diagnostic consideration for COVID-19 survivors

Objective: SARS-CoV-2 infection and its oft-associated illness COVID-19 may lead to neuropsychological deficits, either through direct mechanisms (i.e., neurovirulance) or indirect mechanisms, most notably complications caused by the virus (e.g., stroke) or medical procedures (e.g., intubation). The history of past human coronavirus outbreaks resulting in similar health emergencies suggests there will be a substantial prevalence of post-traumatic stress disorder (PTSD) among COVID-19 survivors. To prepare neuropsychologists for the difficult task of differentiating PTSD-related from neuropathology-related deficits in the oncoming wave of COVID-19 survivors, we integrate research across a spectrum of related areas.Methods: Several areas of literature were reviewed: psychiatric, neurologic, and neuropathological outcomes of SARS and MERS patients; neurological outcomes in COVID-19 survivors; PTSD associated with procedures common to COVID-19 patients; and differentiating neuropsychological deficits due to PTSD from those due to acquired brain injuries in other patient groups.Conclusions: Heightened risk of PTSD occurred in MERS and SARS survivors. While data concerning COVID-19 is lacking, PTSD is known to occur in patient groups who undergo similar hospital courses, including ICU survivors, patients who are intubated and mechanically ventilated, and those that experience delirium. Research with patients who develop PTSD in the context of mild traumatic brain injury further suggests that PTSD may account for some or all of a patient's subjective cognitive complaints and neuropsychological test performance. Recommendations are provided for assessing PTSD in the context of COVID-19.

Cerebrovascular function in hypertension: Does high blood pressure make you old?

The majority of individuals over an age of 60 have hypertension. Elevated blood pressure and older age are associated with very similar changes in brain structure and function. We review the parallel brain changes associated with increasing age and blood pressure. This review focuses on joint associations of aging and elevated blood pressure with neuropsychological function, regional cerebral blood flow responses to cognitive and metabolic challenges, white matter disruptions, grey matter volume, cortical thinning, and neurovascular coupling. Treatment of hypertension ameliorates many of these changes but fails to reverse them. Treatment of hypertension itself appears more successful with better initial brain function. We show evidence that sympathetic and renal influences known to increase blood pressure also impact brain integrity. Possible central mechanisms contributing to the course of hypertension and aging are then suggested. An emphasis is placed on psychologically relevant factors: stress, cardiovascular reactions to stress, and diet/obesity. The contribution of some of these factors to biological aging remains unclear and may provide a starting point for defining the independent and interacting effects of aging and increasing blood pressure on the brain.

Risk and Protective Factors for the Onset of Cognitive Impairment in Korea: A 10-Year Longitudinal Panel Study

OBJECTIVE

This study aimed to examine the associations between multiple modifiable risk/protective factors and the onset of cognitive impairment, using nationally representative panel data spanning 10 years.

METHODS

A total of 7,568 respondents who were cognitively normal at baseline were included and followed up for 10 years using data from the 2006-2016 Korean Longitudinal Study of Ageing. The data were converted into 28,113 person-year observations, and a life table approach and a series of event history models were used to estimate the transition rates to cognitive impairment over time and to examine the influence of time-varying factors on the onset of cognitive impairment. Cognitive impairment was measured using the Korean version of the Mini-Mental State Exam.

RESULTS

About half of the respondents without cognitive impairment at baseline had experienced cognitive impairment by the end of the last interview, and women were more likely than men to experience cognitive impairment during the observation period. Vascular risk factors, hearing loss, socioeconomic status, regular exercise, participation in social activities, and frequent contact with close friends were significantly associated with the onset of cognitive impairment.

CONCLUSION

This investigation of modifiable factors for cognitive impairment using population-based data may lead to the identification of preventive strategies that people could integrate into their lifestyles.

Cortical atrophy mediates the accumulating effects of vascular risk factors on cognitive decline in the Alzheimer's disease spectrum

There are increasing concerns regarding the association of vascular risk factors (VRFs) and cognitive decline in the Alzheimer's disease (AD) spectrum. Currently, we investigated whether the accumulating effects of VRFs influenced gray matter volumes and subsequently led to cognitive decline in the AD spectrum. Mediation analysis was used to explore the association among VRFs, cortical atrophy, and cognition in the AD spectrum. 123 AD spectrum were recruited and VRF scores were constructed. Multivariate linear regression analysis revealed that higher VRF scores were correlated with lower Mini-Mental State Examination scores and higher Alzheimer's Disease Assessment Scale-Cognitive Subscale scores, indicating higher VRF scores lead to severer cognitive decline in the AD spectrum. In addition, subjects with higher VRF scores suffered severe cortical atrophy, especially in medial prefrontal cortex and medial temporal lobe. More importantly, common circuits of VRFs- and cognitive decline associated with gray matter atrophy were identified. Further, using mediation analysis, we demonstrated that cortical atrophy regions significantly mediated the relationship between VRF scores and cognitive decline in the AD spectrum. These findings highlight the importance of accumulating risk in the vascular contribution to AD spectrum, and targeting VRFs may provide new strategies for the therapeutic and prevention of AD.

The association of blood pressure with physical frailty and cognitive function in community-dwelling septuagenarians, octogenarians, and nonagenarians: the SONIC study

We investigated the association of systolic blood pressure (SBP) level with physical frailty and cognitive function in community-dwelling older Japanese. Using the 'Septuagenarians, Octogenarians, Nonagenarians Investigation with Centenarians' survey as the baseline, we performed a cross-sectional analysis of people aged 70 ± 1 (n = 1000), 80 ± 1 (n = 978), and 90 ± 1 (n = 272) years. Medical histories and medications were collected via interviews conducted by medical professionals. Blood pressure (BP), grip strength, gait speed, and cognitive function were examined on site. Trend analysis and multiple regression analysis were used to determine the association of the SBP level with physical frailty and cognitive function. The principal finding was that the association of SBP with physical frailty and cognitive function varied depending on characteristics such as age, physical and cognitive function, and antihypertensive medication use. A lower SBP level was associated with a higher prevalence of physical frailty only among 80-year-olds who were on antihypertensive medication. A significant association was found between higher SBP and lower cognitive function among 70-year-olds, while among 90-year-olds, the opposite was found. No association was found among participants who were 80 years old or among participants of all ages without antihypertensive medication. Our finding that an inverted association between SBP and geriatric syndrome exists suggests that the treatment of older patients must be individualized to prevent geriatric syndrome.

Hemodynamic latency is associated with reduced intelligence across the lifespan: an fMRI DCM study of aging, cerebrovascular integrity, and cognitive ability

Changes in neurovascular coupling are associated with both Alzheimer's disease and vascular dementia in later life, but this may be confounded by cerebrovascular risk. We hypothesized that hemodynamic latency would be associated with reduced cognitive functioning across the lifespan, holding constant demographic and cerebrovascular risk. In 387 adults aged 18-85 (mean = 48.82), dynamic causal modeling was used to estimate the hemodynamic response function in the left and right V1 and V3-ventral regions of the visual cortex in response to a simple checkerboard block design stimulus with minimal cognitive demands. The hemodynamic latency (transit time) in the visual cortex was used to predict general cognitive ability (Full-Scale IQ), controlling for demographic variables (age, race, education, socioeconomic status) and cerebrovascular risk factors (hypertension, alcohol use, smoking, high cholesterol, BMI, type 2 diabetes, cardiac disorders). Increased hemodynamic latency in the visual cortex predicted reduced cognitive function (p < 0.05), holding constant demographic and cerebrovascular risk. Increased alcohol use was associated with reduced overall cognitive function (Full Scale IQ 2.8 pts, p < 0.05), while cardiac disorders (Full Scale IQ 3.3 IQ pts; p < 0.05), high cholesterol (Full Scale IQ 3.9 pts; p < 0.05), and years of education (2 IQ pts/year; p < 0.001) were associated with higher general cognitive ability. Increased hemodynamic latency was associated with reduced executive functioning (p < 0.05) as well as reductions in verbal concept formation (p < 0.05) and the ability to synthesize and analyze abstract visual information (p < 0.01). Hemodynamic latency is associated with reduced cognitive ability across the lifespan, independently of other demographic and cerebrovascular risk factors. Vascular health may predict cognitive ability long before the onset of dementias.

Cerebral microvascular complications of type 2 diabetes: stroke, cognitive dysfunction, and depression

Adults with type 2 diabetes are at an increased risk of developing certain brain or mental disorders, including stroke, dementia, and depression. Although these disorders are not usually considered classic microvascular complications of diabetes, evidence is growing that microvascular dysfunction is one of the key underlying mechanisms. Microvascular dysfunction is a widespread phenomenon in people with diabetes, including effects on the brain. Cerebral microvascular dysfunction is also apparent in adults with prediabetes, suggesting that cerebral microvascular disease processes start before the onset of diabetes. The microvasculature is involved in the regulation of many cerebral processes that when impaired predispose to lacunar and haemorrhagic stroke, cognitive dysfunction, and depression. Main drivers of diabetes-related cerebral microvascular dysfunction are hyperglycaemia, obesity and insulin resistance, and hypertension. Increasing amounts of data from observational studies suggest that diabetes-related microvascular dysfunction is associated with a higher risk of stroke, cognitive dysfunction, and depression. Cerebral outcomes in diabetes might be improved following treatments targeting the pathways through which diabetes damages the microcirculation. These treatments might include drugs that reduce dicarbonyl compounds, augment cerebral insulin signalling, or improve blood-brain barrier permeability and cerebral vasoreactivity.

Alzheimer's Disease: The Link Between Amyloid-β and Neurovascular Dysfunction

While prevailing evidence supports that the amyloid cascade hypothesis is a key component of Alzheimer's disease (AD) pathology, many recent studies indicate that the vascular system is also a major contributor to disease progression. Vascular dysfunction and reduced cerebral blood flow (CBF) occur prior to the accumulation and aggregation of amyloid-β (Aβ) plaques and hyperphosphorylated tau tangles. Although research has predominantly focused on the cellular processes involved with Aβ-mediated neurodegeneration, effects of Aβ on CBF and neurovascular coupling are becoming more evident. This review will describe AD vascular disturbances as they relate to Aβ, including chronic cerebral hypoperfusion, hypertension, altered neurovascular coupling, and deterioration of the blood-brain barrier. In addition, we will describe recent findings about the relationship between these vascular defects and Aβ accumulation with emphasis on in vivo studies utilizing rodent AD models.

Long-Term Blood Pressure Variability Across the Clinical and Biomarker Spectrum of Alzheimer's Disease

BACKGROUND

Elevated blood pressure is linked to cognitive impairment and Alzheimer's disease (AD) biomarker abnormality. However, blood pressure levels vary over time. Less is known about the role of long-term blood pressure variability in cognitive impairment and AD pathophysiology.

OBJECTIVE

Determine whether long-term blood pressure variability is elevated across the clinical and biomarker spectrum of AD.

METHODS

Alzheimer's Disease Neuroimaging Initiative participants (cognitively normal, mild cognitive impairment, AD [n = 1,421]) underwent baseline exam, including blood pressure measurement at 0, 6, and 12 months. A subset (n = 318) underwent baseline lumbar puncture to determine cerebrospinal fluid amyloid-β and phosphorylated tau levels. Clinical groups and biomarker-confirmed AD groups were compared on blood pressure variability over 12 months.

RESULTS

Systolic blood pressure variability was elevated in clinically diagnosed AD dementia (VIM: F2,1195 = 6.657, p = 0.001, η2 = 0.01) compared to cognitively normal participants (p = 0.001), and in mild cognitive impairment relative to cognitively normal participants (p = 0.01). Findings were maintained in biomarker-confirmed AD (VIM: F2,850 = 5.216, p = 0.006, η2 = 0.01), such that systolic blood pressure variability was elevated in biomarker-confirmed dementia due to AD relative to cognitively normal participants (p = 0.005) and in biomarker-confirmed mild cognitive impairment due to AD compared to cognitively normal participants (p = 0.04).

CONCLUSION

Long-term systolic blood pressure variability is elevated in cognitive impairment due to AD. Blood pressure variability may represent an understudied aspect of vascular dysfunction in AD with potential clinical implications.

Cardiorespiratory fitness, blood pressure, and cerebral oxygenation during a dual-task in healthy young males

This study aimed to evaluate the effects of cardiorespiratory fitness (CRF) and mean arterial pressure (MAP) on the prefrontal cortex (PFC) oxygenation and dual-task performance in healthy young males. Changes in the concentration of oxygenated (ΔHbO₂) and deoxygenated hemoglobin (ΔHHb) in the right and left PFC were examined during a cognitive auditory 2-back task. Cognitive performance (2-back task's accuracy) and walking motor performances were measured in single-tasks (single motor and single cognitive) and dual-task (2-back task + walking). Thirty-six young males were ranked according to their V˙O₂peak. The second tertile was excluded to generate two groups of different CRF (high fit group: n = 12 and V˙O₂peak = 56.0 ± 6.7 ml kg^-1 min^-1; low-fit group: n = 12 and V˙O₂peak = 36.7 ± 4.1 ml kg^-1 min^-1). The CRF groups were further split into two subgroups according to 24-h MAP (higher-MAP, lower-MAP). Two-way ANOVA (CRF x n-back conditions) revealed a significant interaction between the CRF and cognitive task condition on 2-back accuracy (p =  .007) and a main effect of CRF on ⊗HHb in the right and left PFC (p < .05). These results suggest that in healthy young males: 1) for CRF, only low-fit individuals demonstrate dual-task costs in accuracy (Dual < Single), and 2) that in comparison to the low-fit group, the high fit-group demonstrated greater changes in PFC oxygenation in ΔHHb, but not ΔHbO₂.

The role of exercise in the reversal of IGF-1 deficiencies in microvascular rarefaction and hypertension

Hypertension has been linked with peripheral and central reductions in vascular density, and with devastating effects on brain function. However, the underlying mechanisms in the relationship between blood pressure and cognitive impairment have yet to be fully elucidated. Here, we review compelling evidence from two lines of inquiry: one that links microvascular rarefaction with insulin-like growth factor 1 (IGF-1) deficiencies, and another which posits that vascular dysfunction precedes hypertension. Based on the findings from experimental and clinical studies, we propose that these lines of evidence converge, and suggest that age-related declines in IGF-1 concentrations precede microvascular rarefaction, initiate an increase in vascular resistance, and therefore are causally linked to onset of hypertension. Physical exercise provides a relevant model for supporting our premise, given the well-established effects of exercise in attenuating vascular dysfunction, hypertension, IGF-1 deficiency, and cognitive decline. We highlight here the role of exercise-induced increases in blood flow in improving vascular integrity and enhancing angiogenesis via the actions of IGF-1, resulting in reversal of rarefaction and hypertension, and enhancement of cerebral blood flow and cognition.

Österreichischer Blutdruckkonsens 2019

Erhöhter Blutdruck bleibt eine Hauptursache von kardiovaskulären Erkrankungen, Behinderung und frühzeitiger Sterblichkeit in Österreich, wobei die Raten an Diagnose, Behandlung und Kontrolle auch in rezenten Studien suboptimal sind. Das Management von Bluthochdruck ist eine häufige Herausforderung für Ärztinnen und Ärzte vieler Fachrichtungen. In einem Versuch, diagnostische und therapeutische Strategien zu standardisieren und letztendlich die Rate an gut kontrollierten Hypertoniker/innen zu erhöhen und dadurch kardiovaskuläre Erkrankungen zu verhindern, haben 13 österreichische medizinische Fachgesellschaften die vorhandene Evidenz zur Prävention, Diagnose, Abklärung, Therapie und Konsequenzen erhöhten Blutdrucks gesichtet. Das hier vorgestellte Ergebnis ist der erste Österreichische Blutdruckkonsens. Die Autoren und die beteiligten Fachgesellschaften sind davon überzeugt, daß es einer gemeinsamen nationalen Anstrengung bedarf, die Blutdruck-assoziierte Morbidität und Mortalität in unserem Land zu verringern.

Diverse cognitive impairment after spinal cord injury is associated with orthostatic hypotension symptom burden

This study: 1) compared cognitive functioning between individuals with chronic (>1 year) spinal cord injury (SCI) and non-injured controls and, 2) assessed associations between symptoms of autonomic dysreflexia and orthostatic hypotension with cognitive functioning in SCI participants with a history of unstable blood pressure (BP). Thirty-two individuals with SCI (C4-L2, American Spinal Injury Association Impairment Scale A-D) and thirty age, sex-matched non-injured controls participated in this study. Participants completed a motor-free neuropsychological test battery assessing 1) memory, 2) attention/concentration/psychomotor speed and, 3) executive function. Nineteen participants with SCI who had injuries ≥T6 and a history of unstable BP also completed the Autonomic Dysfunction Following Spinal Cord Injury (ADFSCI) questionnaire. Cognitive function was significantly lower in people with SCI across measures of memory and executive function compared to non-injured controls. Significant, moderate-to-large associations were observed between cumulative (frequency x severity) orthostatic hypotension and total BP instability symptoms scores, with measures of attention/concentration/psychomotor speed and executive function. These data demonstrate a 10 - 65% reduced performance across specific realms of cognitive functioning in individuals with SCI relative to non-injured controls. Furthermore, cumulative subjective scores for symptoms of unstable BP were associated with diverse cognitive deficits. These findings, in individuals without co-occurring traumatic brain injury, imply cardiovascular dysregulation plays a role in cognitive deficits observed in this population.

Roles of vascular risk factors in the pathogenesis of dementia

The number of people with dementia is rapidly growing along with the aging of society and is becoming a social issue worldwide. The results of recent clinical and basic studies have suggested that vascular risk factors, such as hypertension and diabetes mellitus, affect the pathogenesis of dementia. Cerebrovascular damage due to vascular risk factors directly triggers vascular dementia, and it is becoming more apparent that vascular risk factors also increase the risk of neurodegenerative Alzheimer's disease, which is associated with the accumulation of neurotoxic proteins in the brain. Although disease-modifying therapy for dementia has not yet been established, several studies have shown that the management of vascular risk factors could possibly contribute to reducing the risk of developing dementia, thus making them important targets for dementia prevention. In this article, we review recent findings regarding the relationship between vascular risk factors and dementia, especially focusing on Alzheimer's disease, the underlying molecular mechanisms, and the potential strategies targeting these modifiable risk factors to prevent cognitive decline.

Is Baseline Orthostatic Hypotension Associated With a Decline in Global Cognitive Performance at 4-Year Follow-Up? Data From TILDA (The Irish Longitudinal Study on Ageing)

Background It is postulated that orthostatic hypotension ( OH ), a reduction in blood pressure (≥20/10 mm Hg) within 3 minutes of standing, may increase cognitive decline because of cerebral hypoperfusion. This study assesses the impact of OH on global cognition at 4-year follow-up, and the impact of age and hypertension on this association. Methods and Results Data from waves 1 and 3 of TILDA (The Irish Longitudinal Study on Ageing) were used. Baseline blood pressure response to active stand was assessed using beat-to-beat blood pressure monitoring. Two measures of OH were used-at 40 seconds ( OH 40) and 110 seconds ( OH 110). Global cognition was measured using the Montreal Cognitive Assessment. Mixed-effects Poisson regression assessed whether baseline OH was associated with a decline in global cognition at 4-year follow-up. The analysis was repeated, stratifying by age (age 50-64 years and age ≥65 years), and including an interaction between OH and hypertension. Baseline OH 110 was associated with an increased error rate in Montreal Cognitive Assessment at follow-up (incident rate ratio 1.17, P=0.028). On stratification by age, the association persists in ages 50 to 64 years (incident rate ratio 1.25, P=0.048), but not ages ≥65 years. Including an interaction with hypertension found those with co-existent OH 110 and hypertension (incident rate ratio 1.27, P=0.011), or OH 40 and hypertension (incident rate ratio 1.18, P=0.017), showed an increased error rate; however, those with isolated OH 110, OH 40, or isolated hypertension did not. Conclusions OH is associated with a decline in global cognition at 4-year follow-up, and this association is dependent on age and co-existent hypertension.

Blood Pressure Variability and Progression of Clinical Alzheimer Disease

Blood pressure variability (BPV) has been shown to have predictive value over blood pressure (BP) levels alone in stroke patients. We assessed whether BPV predicts cognitive and functional decline in Alzheimer disease, using data from a randomized trial (NILVAD [A European Multicentre Double-blind Placebo-controlled Phase III Trial of Nilvadipine in Mild to Moderate Alzheimer’s Disease]). Patients with mild-to-moderate Alzheimer disease were included if they had ≥3 office BP measurements available to determine visit-to-visit BPV. Day-to-day BPV was assessed using home BP measurements in a subsample. The variation independent of mean was used to calculate BPV. Outcomes were change in Alzheimer’s Disease Assessment Scale–cognitive subscale-12 and Disability Assessment for Dementia after 1 and 1.5 years. A total of 460 patients aged 72.1 (SD=8.1) years, with mean BP of 134.0/75.1 (10.9/6.3) mm Hg were included. After 1 year, patients in the highest quartile of BPV had deteriorated more on Alzheimer’s Disease Assessment Scale–cognitive subscale compared with patients in the lowest quartile (systolic: β, 2.24 [95% CI, 0.11–4.38], P =0.040; diastolic: β, 2.54 [95% CI, 0.33–4.75] P =0.024). This association was still present after 1.5 years (systolic: β, 2.86 [95% CI, 0.35–5.36], P =0.026; diastolic: β, 3.30 [95% CI, 0.67–5.93], P =0.014). There was no effect of visit-to-visit BPV on Disability Assessment for Dementia. Day-to-day BPV was available for 46 patients. Significant associations were observed between day-to-day BPV and deterioration on Alzheimer’s Disease Assessment Scale–cognitive subscale (systolic: P =0.036) and Disability Assessment for Dementia (systolic: P =0.020; diastolic: P =0.007) after 1 year, but not after 1.5 years. All associations were adjusted for potential confounders, including intervention group. In conclusion, this post hoc analysis indicates that higher visit-to-visit and day-to-day BPV might be associated with progression of Alzheimer disease. Targeting BPV may be a future target to slow decline in patients with Alzheimer disease.

Clinical Trial Registration

URL: https://www.clinicaltrials.gov . Unique identifier: NCT02017340.

Telomere length and cognitive function: Differential patterns across sociodemographic groups

OBJECTIVE

The present study investigates whether associations between telomere length (TL) and cognitive performance across multiple domains are moderated by poverty status and race.

METHOD

Participants were 325 African American and White urban-dwelling adults (M age = 47.9 years; 49.5% African American; 50.2% female; 48.9% living in poverty) from the Healthy Aging in Neighborhoods of Diversity across the Life Span study. TL was assayed from peripheral blood mononuclear cells using quantitative polymerase chain reactions. Multivariable regression analyses examined interactions of TL, poverty status, and race with performance on the following cognitive tests: Trail-Making Test Parts A and B, Digit Span Forward and Backward, semantic verbal fluency, Brief Test of Attention, Benton Visual Retention Test (BVRT), and California Verbal Learning Test-II total learning, short-delay free recall, and long-delay free recall scores. Analyses adjusted for age, sex, and high school-or-greater educational attainment.

RESULTS

Significant three-way interactions of TL × Poverty Status × Race revealed that, among White participants living in poverty, shorter TL was associated with worse performance on Digit Span Forward and Backward (ps<.05). Additionally, significant two-way interactions of TL × Poverty Status revealed that, among all participants living in poverty, shorter TL was associated with worse performance on the Trail-Making Test Part B and the BVRT (ps<.05).

CONCLUSIONS

TL may be differentially associated with aspects of attention, executive functioning, and memory among individuals living in poverty, who may be uniquely vulnerable to adverse effects of shorter telomeres. Replication of these findings is needed to determine their generalizability. (PsycINFO Database Record (c) 2020 APA, all rights reserved).

Assessment of sensory sensitivity through critical flicker fusion frequency thresholds after a maximum voluntary apnoea

INTRODUCTION

The influence of acute exercise on sensory sensitivity (SS) differs according to the type and duration of exercise performed. In the present study, we assessed changes on SS soon after a maximal dynamic apnoea.

METHODS

Thirty-nine experienced male breath-hold divers were recruited. Critical flicker fusion frequency (CFFF) thresholds were used to measure SS. Thresholds were determined before and after a maximal dynamic apnoea. Immediately after surfacing, heart rate and oxygen saturation (SpO₂) were recorded for two minutes.

RESULTS

After maximal dynamic apnoea, SpO₂ was significantly decreased (from mean 97.3% pre-dive to mean 63.1% post-dive; P < 0.0001; η2 P = 0.86), but this acute hypoxaemia did not trigger changes in SS (post-dive value 102% of baseline; P = 0.22; η2 P = 0.03). Pearson correlation analysis revealed a moderate association between SS with swimming speed (r = 0.423) and apnoea time (r = -0.404).

CONCLUSIONS

A maximal dynamic apnoea did not produce changes in central nervous system fatigue or cortical arousal. We found no relationship between the hypoxaemia level reached after a maximal apnoea and changes in the CFFF thresholds. This study suggests that the time of exposure to hypoxia during a maximal voluntary apnoea is not enough to produce changes in SS.

Predictors for Blood Pressure Reduction in American Latinos: Secondary Analysis of the Adelgaza Program Data

Little is known about factors that predict blood pressure (BP) reduction in overweight American Latinos. The aim of this secondary analysis was to explore predictors of changes in mean systolic and diastolic BPs over an 8-week weight loss intervention period in a sample of 54 overweight American Latinos using data collected during the Adelgaza trial. Baseline BP, exercise energy use (in units of metabolic equivalent of task), weight change, average daily intake of calories from beverages, average daily intake of calories from fat, age, and gender were considered as potential predictors of reductions in BP, as measured at baseline, 3, and 8 weeks. Baseline characteristics were as follows: mean age 45.3 (SD = 10.8) years, 31.5% male, 61.1% born in the United States. Mean baseline systolic and diastolic BPs were 122.1 (SD = 14.4) mmHg and 76.6 (SD = 9.8) mmHg, respectively. Both baseline systolic and diastolic BPs predicted reductions in systolic BP after adjusting for other factors (p < .001). None of the nine variables predicted reductions in diastolic BP (p > .05). This finding suggests that overweight American Latinos with higher baseline systolic or diastolic BP should be identified and provided with early intervention education to achieve better hypertension management or prevention.

High exposure to statins decrease the risk of new-onset dementia: A nationwide population-based longitudinal cohort study

Several studies have shown that statin users have a lower risk of new-onset dementia (NOD) compared nonusers. However, other studies have shown opposite results. In this study, we investigated the association between the use of statins and the development of NOD.This was a longitudinal cohort study using data from claim forms submitted to the Taiwanese Bureau of National Health Insurance. The study included patients with NOD and non-NOD subjects from January 2002 to December 2013. We estimated the hazard ratios (HRs) of NOD associated with statin use, whereas nonuser subjects were used as a reference group.A total of 19,522 NOD cases were identified in 100,610 hyperlipidemic patients during the study period. The risk of NOD, after adjusting for sex, age, comorbidities, and concurrent medication, was lower among statin users than nonusers (HR 0.95, 95% CI [confidence interval] 0.94-0.96; P < .001). The adjusted HRs for NOD were 1.53 (95% CI, 1.45-1.62), 0.63 (95% CI, 0.57-0.71), and 0.34 (95% CI, 0.30-0.38) when the cumulative defined daily doses ranged from 28 to 365, 366 to 730, and more than 730 relative to nonusers, respectively.We concluded that statin use is associated with a decreased NOD risk. The protective effect of statins for NOD seemed to be related to high exposure to statins. This study also highlights that high exposure to statins has a dose-response effect on lowering NOD risk.

LRRTM4 and PCSK5 Genetic Polymorphisms as Markers for Cognitive Impairment in A Hypotensive Aging Population: A Genome-Wide Association Study in Taiwan

Hypotension can affect cerebral perfusion and worsen cognitive outcomes. The prevalence of low blood pressure (BP) rises with increasing age. To our knowledge, no study has examined the genetic biomarkers for hypotension-related cognitive impairment (CI) yet. Utilizing the population-based genome-wide study of the Taiwan Biobank containing the data of 2533 healthy aging subjects, we found after adjustments for age, sex, education years, and principal components at a suggestive level of 1 × 10⁻⁵ that minor alleles of leucine rich repeat transmembrane neuronal 4 (LRRTM4) (rs13388459, rs1075716, rs62171995, rs17406146, rs2077823, and rs62170897), proprotein convertase subtilisin/kexin type 5 (PCSK5) (rs10521467), and the intergenic variation rs117129097 (the nearby gene: TMEM132C) are risk factors for CI in hypotensive subjects. Except for rs117129097, these single nucleotide polymorphisms (SNPs) were not markers per se for CI or for BP regulation. However, we found a suggestive interaction effect between each of the eight SNPs and hypotension on CI risk. In the hypotensive participants, those carrying minor alleles were associated with a higher incidence of CI in an additive manner than were those carrying major alleles (2 × 10⁻⁴ to 9 × 10⁻⁷). Intensive BP lowering in elderly patients carrying a minor allele of the eight identified SNPs should raise cautions to prevent a potential treatment-induced neurodegeneration.

Executive function in systemic arterial hypertension: A systematic review

Systemic arterial hypertension (SAH) may be associated with worse cognitive performance, especially in tasks that evaluate the executive functions (EF).

OBJECTIVE

we aimed to review the evidence regarding which components of executive functions are most affected in adults with SAH.

METHODS

this systematic review used the PRISMA statement for searching Pubmed, Scielo and Lilacs databases with the keywords "executive function OR executive functioning AND hypertension".

RESULTS

EF tasks were divided into shifting, inhibitory control and updating. A total of 9 cross-sectional and 3 longitudinal studies were selected. Only 3 studies did not report worse performance among SAH patients on EF tasks when compared to normotensive controls. The measures of shifting and inhibitory control were the most frequently investigated and reported as altered among SAH individuals, assessed mainly by the Stroop Test and Trail-Making Test part B, respectively.

CONCLUSION

inhibitory control and shifting are the EF components most influenced by SAH. The results of this review may contribute to the devising of hypotheses about mechanisms underlying these cognitive impairments.

Pathological and cognitive changes in patients with type 2 diabetes mellitus and comorbid MCI and protective hypoglycemic therapies: a narrative review

Type 2 diabetes mellitus (T2DM) is becoming a significant health issue worldwide. Many studies support the hypothesis that patients with T2DM have a higher-than-expected incidence of mild cognitive impairment (MCI) than individuals without diabetes. Based on the results from recent studies, MCI might be associated with the effects of T2DM on glucose metabolism and brain atrophy. As a narrative review, we will illuminate pathological and cognitive changes in patients with T2DM and comorbid MCI and protective hypoglycemic therapies. The early abnormal signs of cognition must be elucidated, and extensive investigations are needed to develop improved therapies for use in the clinic.

[Cognitive impairment in patients with metabolic syndrome. The current treatment possibilities]

AIM

To study the effect of therapy with cytoflavin on cognitive function in patients with metabolic syndrome (MS).

MATERIAL AND METHODS

The randomized controlled open study included 156 patients with MS. The mean age was 41.27±5.16 years. The duration of observation was 16 weeks. The main group of patients (n=78) received cytoflavin in the dose of 2 tablets 2 times a day. Patients in the control group (n=78) received basic therapy. All patients underwent neuropsychological testing at baseline, after 2 months and at the end of the study. Cognitive evoked potentials (Р300) were recorded to assess cognitive functions. The levels of plasma glucose and lipid profile were measured.

RESULTS

Cytoflavin improved cognitive functions. Two months after treatment, the results of neuropsychological testing and electrophysiological study were better in the main group compared to the control group.

Age Modulates the Association of Caffeine Intake With Cognition and With Gray Matter in Elderly Diabetics

BACKGROUND

The association between caffeine and cognitive performance has not been tested in older individuals with type 2 diabetes (T2D). Its association with brain volume in T2D has been tested only in animals.

METHODS

We examined the association of caffeine with cognitive function and brain volume in a sample of elderly diabetics participating in the Israel Diabetes and Cognitive Decline Study (n = 638) and the moderating effect of age on this association. In a subsample (n = 185) with magnetic resonance imaging, we also examined these associations with gray and white matter volumes (GM/WM).

RESULTS

Using linear regression adjusting for cognition-related covariates, we found that higher caffeine intake was associated with better function in overall cognition (p = .018), attention/working memory (p = .002), executive functioning (p = .047), and semantic categorization (p = .026). Interaction analyses of caffeine intake with age were significant for semantic categorization (p = .025), and approached significance for overall cognition (p = .066). This association was driven by the older group (above-median) for whom the association of caffeine intake with semantic categorization (p = .001), attention/working memory (p = .007), executive functioning (p = .005), and overall cognition (p = .002) were significant. In the magnetic resonance imaging subsample, there was an interaction (p = .034) of caffeine intake with age for GM volume; in the older group, higher caffeine intake was associated with greater GM volume (β = .198, p = .033).

CONCLUSIONS

Caffeine intake may have a beneficial role in cognitive functioning of elderly adults with T2D, which may be moderated by age. Greater GM volume may be a mechanism underlying the association of higher caffeine intake with better cognitive function.

Orthostatic hypotension and cognition in older adults: A systematic review and meta-analysis

BACKGROUND

Orthostatic hypotension (OH) is common in older adults with reported prevalence rates of 5-40%. A direct link between OH and cognitive performance has been proposed due to impaired vascular autoregulation.

AIM

To systematically assess the literature of the association between OH and cognitive performance in older adults.

METHODS

Literature search of MEDLINE, Embase, Cochrane Central Register of Controlled Trials and PsycINFO from inception to May 2017. Studies were included if OH and cognition were assessed in subjects of mean or median age ≥65 years. Risk of bias was assessed with the Newcastle Ottawa Scale.

RESULTS

Of 3266 studies screened, 32 studies (22 cross-sectional; 10 longitudinal) reporting data of 28,980 individuals were included. OH prevalence ranged from 3.3% to 58%. Of the 32 studies, 18 reported an association between OH and worse cognitive performance and 14 reported no association. Mini Mental State Examination (MMSE) was the most commonly used cognitive assessment tool. Studies using more than one cognitive assessment tool were more likely to find an association between OH and worse cognition. OH was significantly associated with a lower MMSE mean score (mean difference - 0.51 (95% CI: -0.85, -0.17, p = 0.003)) and an increased risk of cognitive impairment (OR 1.19 (95% CI, 1.00-1.42, p = 0.048)).

CONCLUSIONS

OH is common in older populations and is associated with worse cognition expressed as lower MMSE scores. Use of MMSE alone as a cognitive assessment tool may underestimate the association. It is yet unclear whether the association between OH and worse cognitive performance is causative.

Exercise Improves Vascular Function, but does this Translate to the Brain?

The number of adults with Alzheimer’s disease (AD) or related dementia is expected to increase exponentially. Interventions aimed to reduce the risk and progression of AD and dementia are critical to the prevention and treatment of this devastating disease. Aging and cardiovascular disease risk factors are associated with reduced vascular function, which can have important clinical implications, including brain health. The age-associated increase in blood pressure and impairment in vascular function may be attenuated or even reversed through lifestyle behaviors. Greater volumes of habitual exercise and higher cardiorespiratory fitness are associated with beneficial effects on vascular health and cognition. Exercise and cardiorespiratory fitness may be most important during midlife, as physical activity and cardiorespiratory fitness during the middle-aged years are associated with future cognitive function. The extent to which exercise, and more specifically aerobic exercise, influences the cerebral circulation is not well established. In this review, we present our working hypothesis showing how cerebrovascular function may be a mediating factor underlying the association between exercise and cognition, as well as discuss recent studies evaluating the effect of exercise interventions on the cerebral circulation.

Neurovascular coupling during cognitive activity in adults with controlled hypertension

Hypertension, even when controlled, may accelerate arterial stiffening and impair the ability of the cerebrovasculature to increase blood flow to support neural activity, i.e., neurovascular coupling (NVC). Optimal NVC depends on continuous, nonpulsatile flow, which is partially determined by extra- and intracranial vessel function. We sought to compare extra- and intracranial hemodynamics during cognitive activity (Stroop task) in 30 middle-aged, well-controlled medicated hypertensive and 30 age-, sex-, and body mass index (BMI)-matched nonhypertensive adults (56 ± 6 years, 28.2 ± 2.9 kg/m2 BMI; 32 men). Aortic and carotid (single point) pulse wave velocity (PWV) were assessed via tonometry and ultrasound, respectively. Carotid and middle cerebral artery (MCA) blood velocity pulsatility were measured via ultrasound and Doppler. Prefrontal cortex (PFC) oxygenation was measured via tissue saturation index (TSI) using near-infrared spectroscopy. Accuracy and reaction times were computed to assess cognitive performance. Stroop performance was similar between groups ( P > 0.01). Aortic and carotid PWV increased, carotid flow pulsatility decreased ( P < 0.01), and MCA flow pulsatility and PFC TSI were maintained during Stroop ( P > 0.01). Our findings indicate that middle-age adults with medically controlled hypertension and adults without hypertension demonstrate similar intra- and extracranial cerebrovascular reactivity during cognitive engagement. Despite increases in large artery stiffness, middle-aged adults with controlled hypertension and without hypertension exhibit reductions in extracranial flow pulsatility during cognitive engagement that may be part of a concerted cerebrovascular response to support downstream cerebral oxygenation and overall NVC.

NEW & NOTEWORTHY Hypertension is associated with accelerated arterial stiffening, which may alter extra- and intracranial vascular reactivity during cognitive activity and impair neurovascular coupling. Middle-aged adults with medicated hypertension exhibit similar neurovascular coupling and extra-/intracranial vascular reactivity during sustained cognitive activity. Extracranial modulation of central hemodynamics may be an important component of optimal neurovascular coupling.

Association of Blood Pressure and Arterial Stiffness With Cognition in 2 Population-Based Child and Adult Cohorts

Background High blood pressure levels and higher arterial stiffness have been shown to be associated with lower cognition during adulthood, possibly by accumulative changes over time. However, vascular factors may already affect the brain during early life. Methods and Results We examined the relation between cognition and vascular factors within 5853 children from the Generation R Study (mean age 6.2 years) and 5187 adults from the Rotterdam Study (mean age 61.8 years). Diastolic and systolic blood pressure and arterial stiffness were assessed, the latter by measuring pulse-wave velocity and pulse pressure. For cognition, the Generation R Study relied on nonverbal intelligence, whereas the Rotterdam Study relied on a cognitive test battery to calculate the g-factor, a measure of global cognition. In the Generation R Study, standardized diastolic blood pressure showed a significant association with standardized nonverbal intelligence (β=-0.030, 95% confidence interval=[-0.054; -0.005]) after full adjustment. This association held up after excluding the top diastolic blood pressure decile (β=-0.042 [-0.075; -0.009]), suggesting that the relation holds in normotensives. Within the Rotterdam Study, standardized cognition associated linearly with standardized systolic blood pressure (β=-0.036 [-0.060; -0.012]), standardized pulse-wave velocity (β=-0.064 [-0.095; -0.033]), and standardized pulse pressure (β=-0.044 [-0.069; -0.020], and nonlinearly with standardized diastolic blood pressure (quadratic term β=-0.032 [-0.049; -0.015]) after full adjustment. Conclusions Blood pressure and cognition may already be related in the general population during early childhood, albeit differently than during adulthood.

Evidence against a cognitive advantage in the older bilingual population

Recent evidence has challenged long-standing claims that multi-language acquisition confers long-term advantages in executive function and may protect against age-related cognitive deterioration. We assessed evidence for a bilingual advantage in older monolingual and bilingual residents matched on age, gender, and socioeconomic status. A comprehensive battery of tests was administered to measure non-verbal reasoning, working memory capacity, visuo-spatial memory, response inhibition, problem solving, and language proficiency. Analyses, including Bayes factors, revealed comparable performance in both groups, with no significant differences on any task (and the only trend, found for the Tower of London task performance, indicated a monolingual advantage). Overall, therefore, our findings run counter to the bilingual advantage hypothesis. We consider the implications of our study and offer suggestions for future work in this area.

Hypertension-Induced Cerebral Small Vessel Disease Leading to Cognitive Impairment

Objective:

Alzheimer's disease and vascular dementia are responsible for more than 80% of dementia cases. These two conditions share common risk factors including hypertension. Cerebral small vessel disease (CSVD) is strongly associated with both hypertension and cognitive impairment. In this review, we identify the pathophysiological changes in CSVD that are caused by hypertension and further explore the relationship between CSVD and cognitive impairment.

Data Sources:

We searched and scanned the PubMed database for recently published literatures up to December 2017. We used the keywords of “hypertension”, “cerebral small vessel disease”, “white matter lesions”, “enlarged perivascular spaces”, “lacunar infarcts”, “cerebral microbleeds”, and “cognitive impairment” in the database of PubMed.

Study Selection:

Articles were obtained and reviewed to analyze the hypertension-induced pathophysiological changes that occur in CSVD and the correlation between CSVD and cognitive impairment.

Results:

In recent years, studies have demonstrated that hypertension-related changes (e.g., small vascular lesions, inflammatory reactions, hypoperfusion, oxidative stress, damage to autoregulatory processes and the blood-brain barrier, and cerebral amyloid angiopathy) can occur over time in cerebral small vessels, potentially leading to lower cognitive function when blood pressure (BP) control is poor or lacking. Both isolated and co-occurrent CSVD can lead to cognitive deterioration, and this effect may be attributable to a dysfunction in either the cholinergic system or the functionality of cortical and subcortical tracts.

Conclusions:

We explore the currently available evidence about the hypertensive vasculopathy and inflammatory changes that occur in CSVD. Both are vital prognostic indicators of the development of cognitive impairment. Future studies should be performed to validate the relationship between BP levels and CSVD progression and between the numbers, volumes, and anatomical locations of CSVD and cognitive impairment.

The Hippocampal Neuro-Glio-Vascular Network: Metabolic Vulnerability and Potential Neurogenic Regeneration in Disease

Brain metabolism is a fragile balance between nutrient/oxygen supply provided by the blood and neuronal/glial demand. Small perturbations in these parameters are necessary for proper homeostatic functioning and information processing, but can also cause significant damage and cell death if dysregulated. During embryonic and early post-natal development, massive neurogenesis occurs, a process that continues at a limited rate in adulthood in two neurogenic niches, one in the lateral ventricle and the other in the hippocampal dentate gyrus. When metabolic demand does not correspond with supply, which can occur dramatically in the case of hypoxia or ischemia, or more subtly in the case of neuropsychiatric or neurodegenerative disorders, both of these neurogenic niches can respond—either in a beneficial manner, to regenerate damaged or lost tissue, or in a detrimental fashion—creating aberrant synaptic connections. In this review, we focus on the complex relationship that exists between the cerebral vasculature and neurogenesis across development and in disease states including hypoxic-ischemic injury, hypertension, diabetes mellitus, and Alzheimer’s disease. Although there is still much to be elucidated, we are beginning to appreciate how neurogenesis may help or harm the metabolically-injured brain, in the hopes that these insights can be used to tailor novel therapeutics to regenerate damaged tissue after injury.

Lower blood pressure during antihypertensive treatment is associated with higher all-cause mortality and accelerated cognitive decline in the oldest-old. Data from the Leiden 85-plus Study

BACKGROUND

the appropriateness of lowering systolic blood pressure remains controversial in the oldest-old. We tested whether systolic blood pressure is associated with all-cause mortality and change in cognitive function for patients prescribed antihypertensive treatment and those without treatment.

METHODS

we studied participants in the population-based Leiden 85-plus cohort study. Baseline systolic blood pressure and use of antihypertensive treatment were predictors; all-cause mortality and change in cognitive function measured using the Mini-Mental State Examination were the outcomes. Grip strength was measured as a proxy for physical frailty. We used Cox proportional hazards and mixed-effects linear regression models to analyse the relationship between systolic blood pressure and both time to death and change in cognitive function. In sensitivity analyses, we excluded deaths within 1 year and restricted analyses to participants without a history of cardiovascular disease.

RESULTS

of 570 participants, 249 (44%) were prescribed antihypertensive therapy. All-cause mortality was higher in participants with lower blood pressure prescribed antihypertensive treatment (HR 1.29 per 10 mmHg lower systolic blood pressure, 95% CI 1.15-1.46, P < 0.001). Participants taking antihypertensives showed an association between accelerated cognitive decline and lower blood pressure (annual mean change -0.35 points per 10 mmHg lower systolic blood pressure, 95% CI -0.60, -0.11, P = 0.004); decline in cognition was more rapid in those with lower hand grip strength. In participants not prescribed antihypertensive treatment, no significant associations were seen between blood pressure and either mortality or cognitive decline.

CONCLUSIONS

lower systolic blood pressure in the oldest-old taking antihypertensives was associated with higher mortality and faster decline in cognitive function.

Associations between waist circumference, metabolic risk and executive function in adolescents: A cross-sectional mediation analysis

The main objective of this study was to investigate the associations between waist circumference, metabolic risk factors, and executive function in adolescents. Methods: The study was cross-sectional and included 558 adolescents (mean age 14.2 years). Anthropometrics and systolic blood pressure (sysBP) were measured and fasting blood samples were analyzed for metabolic risk factors. A metabolic risk factor cluster score (MetS-cluster score) was computed from the sum of standardized sysBP, triglycerides (TG), inverse high-density lipid cholesterol (HDLc) and insulin resistance (homeostasis model assessment). Cognitive control was measured with a modified flanker task. Results: Regression analyses indicated that after controlling for demographic variables, HDLc exhibited a negative and TG a positive association with flanker reaction time (RT). Waist circumference did not demonstrate a statistically significant total association with the cognitive outcomes. In structural equation modeling, waist circumference displayed an indirect positive association with incongruent RT through a higher MetS-cluster score and through lower HDLc. The only statistically significant direct association between waist circumference and the cognitive outcomes was for incongruent RT in the model including HDLc as mediator. Conclusions: These findings are consonant with the previous literature reporting an adverse association between certain metabolic risk factors and cognitive control. Accordingly, these results suggest specificity between metabolic risk factors and cognitive control outcomes. Further, results of the present study, although cross-sectional, provide new evidence that specific metabolic risk factors may mediate an indirect association between adiposity and cognitive control in adolescents, even though a direct association between these variables was not observed. However, taking the cross-sectional study design into consideration, these results should be interpreted with caution and future longitudinal or experimental studies should verify the findings of this study.

Effects of Blood Pressure in the Early Phase of Ischemic Stroke and Stroke Subtype on Poststroke Cognitive Impairment

BACKGROUND AND PURPOSE

Blood pressure (BP) control in the early phase of stroke is controversial to reduce the risk of poststroke cognitive impairment (PSCI). This study was to investigate the impact of BP levels in the early phase of ischemic stroke and stroke subtype on PSCI.

METHODS

Seven hundred and ninety-six patients with acute ischemic stroke were included. Cognitive function was assessed after stroke onset using the Montreal Cognitive Assessment. Patients were divided into quintiles according to systolic BP and diastolic BP levels in the early phase. Subtype analyses were according to Trial of ORG 10172 in Acute Stroke Treatment classification (infarct cause) and Oxfordshire Community Stroke Project classification (infarct location).

RESULTS

After adjusting for multiple variables, the quintiles with the lowest systolic BP (Q1, 102-127 mm Hg) and with the highest systolic BP (Q5, 171-215 mm Hg) were associated with increased PSCI risk (odds ratio, 1.83; 95% confidence interval, 1.64-2.28; P=0.007 in Q1; odds ratio, 2.32; 95% confidence interval, 1.74-2.90; P<0.001 in Q5) at 3 months as compared with the middle quintile (Q3, 143-158 mm Hg). Similar association was found in diastolic BP quintiles. The analysis of cerebral infarction subtype demonstrated that both large artery atherosclerosis and total anterior circulation infarct were associated with increased risk of PSCI at 3 months after adjusting for multiple variables (large artery atherosclerosis: odds ratio, 1.42; 95% confidence interval, 1.06-1.90; P=0.031; total anterior circulation infarct: odds ratio, 1.68; 95% confidence interval, 1.32-2.15; P=0.001).

CONCLUSIONS

Lower or higher BP in the early phase of ischemic stroke was correlated with increased PSCI risk at 3 months. Maintaining systolic/diastolic BP in the levels of 143 to 158/93 to 102 mm Hg might be beneficial to reduce the occurrence of PSCI. Moreover, large artery atherosclerosis subtype and total anterior circulation infarct subtype were correlated with increased PSCI risk at 3 months.

CLINICAL TRIAL REGISTRATION

URL: https://www.chictr.org. Unique identifier: ChiCTR-TRC-14004804.

Alteration in Brain Functional and Effective Connectivity in Subjects With Hypertension

To reveal the physiological mechanism of the cognitive decline in subjects with hypertension, the functional connectivity (FC) was assessed by using the wavelet phase coherence (WPCO), and effective connectivity (EC) was assessed by using the coupling strength (CS) of near-infrared spectroscopy (NIRS) signals. NIRS signals were continuously recorded from the prefrontal cortex, sensorimotor cortex, and occipital lobes of 13 hypertensive patients (hypertension group, 70 ± 6.5 years old) and 16 elderly healthy subjects (control group, 71 ± 5.5 years old) in resting and standing periods. WPCO and CS were calculated in four frequency intervals: I, 0.6–2; II, 0.145–0.6; III, 0.052–0.145; and IV, 0.021–0.052 Hz. CS quantifies coupling amplitude. In comparison with the control group, the hypertension group showed significantly decreased (p < 0.05) WPCO and CS in intervals III and IV and in the resting and standing states. WPCO and CS were significantly decreased in the resting state compared with those in the standing state in the hypertension group (p < 0.05). Decreased WPCO and CS indicated a reduced network interaction, suggesting disturbed neurovascular coupling in subjects with hypertension. Compared with the control group, the hypertension group showed significantly lower Mini-Mental State Examination (MMSE) (p = 0.028) and Montreal Cognitive Assessment (MoCA) scores (p = 0.011). In the hypertension group, correlation analysis showed that WPCO and CS were significantly positively correlated with MMSE and MoCA scores, respectively. These findings may provide evidence of impaired cognitive function in hypertension and can enhance the understanding on neurovascular coupling.

Exercise and circulating BDNF: Mechanisms of release and implications for the design of exercise interventions

Engagement in regular bouts of exercise confers numerous positive effects on brain health across the lifespan. Acute bouts of exercise transiently improve cognitive function, while long-term exercise training stimulates brain plasticity, improves brain function, and helps to stave off neurological disease. The action of brain-derived neurotrophic factor (BDNF) is a candidate mechanism underlying these exercise-induced benefits and is the subject of considerable attention in the exercise-brain health literature. It is well established that acute exercise increases circulating levels of BDNF and numerous studies have sought to characterize this response for the purpose of improving brain health. Despite the interest in BDNF responses to exercise, little focus has been given to understanding the sources and mechanisms that underlie this response for the purpose of deliberately increasing circulating levels of BDNF. Here we review evidence to support that exploiting these mechanisms of BDNF release can help to optimize brain plasticity outcomes via exercise interventions, which could be especially relevant in the context of multimodal training (i.e., exercise and cognitive stimulation). Therefore, the purpose of this paper is to review the candidate sources of BDNF during exercise and the mechanisms of release. As well, we discuss strategies for maximizing BDNF responses to exercise, and propose novel research directions for advancing our understanding of these mechanisms.