Orthostatic hypotension associated with executive dysfunction in mild cognitive impairment

Efficacy, safety, and response predictors of Astragalus in patients with mild to moderate Alzheimer's disease: A study protocol of an assessor-blind, statistician-blind open-label randomized controlled trial

Background

This pragmatic clinical trial aims to determine the efficacy and safety of add-on Astragalus membranaceus (AM) for cognition and non-cognition in patients with of mild to moderate Alzheimer's disease complicated with orthostatic hypotension in orthostatic hypotension, elucidate the underlying mechanisms, identify related response predictors, and explore effective drug components.

Methods

This is an add-on, assessor-blinded, parallel, pragmatic, randomized controlled trial. At least 66 adults with mild to moderate Alzheimer's disease (AD) and OH aged 50-85 years will be recruited. Participants will be randomized in a 1:1:1 ratio to receive 24 weeks of routine care or add-on low dose AM or add-on high dose AM group. The primary efficacy outcome will be measured by the Alzheimer's Disease Assessment Scale-Cognitive Subscale, Chinese version. Secondary efficacy outcome assessment will include neuropsychological tests, blood pressure, plasma biomarkers, multimodal electroencephalograms, and neuroimaging. Safety outcome measures will include physical examinations, vital signs, electrocardiography, laboratory tests (such as hematologic and blood chemical tests), and adverse event records.

Ethics and dissemination

This trial was approved and supervised by Fujian Medical University Union Hospital (2021KJCX040). Independent results, findings will be published in peer-reviewed journals and presented at national and international conferences.

Trial registration number

NCT05647473; ClinicalTrials.gov Identifier.

Cognitive impairment in multiple sclerosis: from phenomenology to neurobiological mechanisms

Multiple sclerosis (MS) is an autoimmune-mediated disease of the central nervous system characterized by inflammation, demyelination and chronic progressive neurodegeneration. Among its broad and unpredictable range of clinical symptoms, cognitive impairment (CI) is a common and disabling feature greatly affecting the patients' quality of life. Its prevalence is 20% up to 88% with a wide variety depending on the phenotype of MS, with highest frequency and severity in primary progressive MS. Involving different cognitive domains, CI is often associated with depression and other neuropsychiatric symptoms, but usually not correlated with motor and other deficits, suggesting different pathophysiological mechanisms. While no specific neuropathological data for CI in MS are available, modern research has provided evidence that it arises from the disease-specific brain alterations. Multimodal neuroimaging, besides structural changes of cortical and deep subcortical gray and white matter, exhibited dysfunction of fronto-parietal, thalamo-hippocampal, default mode and cognition-related networks, disruption of inter-network connections and involvement of the γ-aminobutyric acid (GABA) system. This provided a conceptual framework to explain how aberrant pathophysiological processes, including oxidative stress, mitochondrial dysfunction, autoimmune reactions and disruption of essential signaling pathways predict/cause specific disorders of cognition. CI in MS is related to multi-regional patterns of cerebral disturbances, although its complex pathogenic mechanisms await further elucidation. This article, based on systematic analysis of PubMed, Google Scholar and Cochrane Library, reviews current epidemiological, clinical, neuroimaging and pathogenetic evidence that could aid early identification of CI in MS and inform about new therapeutic targets and strategies.

Pathobiology of Cognitive Impairment in Parkinson Disease: Challenges and Outlooks

Cognitive impairment (CI) is a characteristic non-motor feature of Parkinson disease (PD) that poses a severe burden on the patients and caregivers, yet relatively little is known about its pathobiology. Cognitive deficits are evident throughout the course of PD, with around 25% of subtle cognitive decline and mild CI (MCI) at the time of diagnosis and up to 83% of patients developing dementia after 20 years. The heterogeneity of cognitive phenotypes suggests that a common neuropathological process, characterized by progressive degeneration of the dopaminergic striatonigral system and of many other neuronal systems, results not only in structural deficits but also extensive changes of functional neuronal network activities and neurotransmitter dysfunctions. Modern neuroimaging studies revealed multilocular cortical and subcortical atrophies and alterations in intrinsic neuronal connectivities. The decreased functional connectivity (FC) of the default mode network (DMN) in the bilateral prefrontal cortex is affected already before the development of clinical CI and in the absence of structural changes. Longitudinal cognitive decline is associated with frontostriatal and limbic affections, white matter microlesions and changes between multiple functional neuronal networks, including thalamo-insular, frontoparietal and attention networks, the cholinergic forebrain and the noradrenergic system. Superimposed Alzheimer-related (and other concomitant) pathologies due to interactions between α-synuclein, tau-protein and β-amyloid contribute to dementia pathogenesis in both PD and dementia with Lewy bodies (DLB). To further elucidate the interaction of the pathomechanisms responsible for CI in PD, well-designed longitudinal clinico-pathological studies are warranted that are supported by fluid and sophisticated imaging biomarkers as a basis for better early diagnosis and future disease-modifying therapies.

Orthostatic hypotension and neurocognitive disorders in older women: Results from the EPIDOS cohort study

BACKGROUND

Although it is well-admitted that cardiovascular health affects cognition, the association between orthostatic hypotension (OH) and cognition remains unclear. The objectives of the present study were i) to determine among the EPIDOS cohort (EPIdémiologie de l'OStéoporose) whether OH was cross-sectionally associated with cognitive impairment at baseline, and ii) whether baseline OH could predict incident cognitive decline after 7 years of follow-up.

METHODS

Systolic and Diastolic Blood Pressure (SBP and DBP) changes while standing (ie, ΔSBP and ΔDBP, in %) were measured at baseline among 2,715 community-dwelling older women aged 75 years and older using no antihypertensive drugs from the French EPIDOS cohort. OH was defined as a decrease in SBP ≥20 mmHg and/or a decrease in DBP ≥10 mmHg within 3 min after standing. Cognitive impairment was defined as a Short Portable Mental Status Questionnaire (SPMSQ) score <8 (/10). Among those without cognitive impairment at baseline, a possible incident onset of cognitive decline was then sought after 7 years of follow-up among 257 participants.

RESULTS

Baseline ΔSBP was associated with baseline cognitive impairment (adjusted OR = 1.01, p = 0.047), but not with incident onset of cognitive decline after 7 years (adjusted OR = 0.98, p = 0.371). Neither baseline OH nor baseline ΔDBP were associated with cognitive impairment neither at baseline (p = 0.426 and p = 0.325 respectively) nor after 7 years (p = 0.180 and p = 0.345 respectively).

CONCLUSIONS

SBP drop while standing, but neither OH per se nor DBP drop while standing, was associated with baseline cognitive impairment in older women. The relationship between OH and cognitive impairment appears more complex than previously expected.

Trajectories of Cognitive Impairment in Adults Bearing Vascular Risk Factors, with or without Diagnosis of Mild Cognitive Impairment: Findings from a Longitudinal Study Assessing Executive Functions, Memory, and Social Cognition

With the aging of the population, a key concern of both societies and health services is to keep the population cognitively healthy until the maximum age limit. It is a well-known fact that vascular aging has a negative effect on the cognitive skills of adults, putting them at greater risk of developing dementia. The present longitudinal study aimed to evaluate the main dimensions of cognition in two pathological groups with different health profiles: a group of adults with vascular risk factors (VRF) (n = 35) and a group of adults with vascular risk factors and mild cognitive impairment (VRF + MCI) (n = 35). The two groups were matched in age, education, and gender. They were assessed with extensive neuropsychological testing at three different times with a distance of about 8 months between them; the assessment regarded executive functions, memory capacity, and Theory of Mind abilities. The analyses carried out were (a) mixed-measures ANOVA, (b) repeated measures ANOVA, and (c) ANOVA. The findings showed that global cognitive status and short-term memory are the main cognitive abilities that decline in community dwelling people bearing VRF. Hence, this group of adults should be examined at least every 2 years for this decline. As regards people with both VRF and MCI, it seems that the assessment of Theory of Mind abilities can better capture their further impairment. Global cognitive status, task/rule switching function, and long-term memory (delayed verbal recall) were revealed as the abilities that clearly and steadily differentiate VRF people with and without MCI.

Myocardial Infarction Predisposes Neurodegenerative Diseases

Cardiovascular disorders, e.g., atherosclerosis and hypertension, increase susceptibility to neurodegenerative diseases, like dementia and Alzheimer's disease (AD), with undetermined mechanisms. Moreover, whether myocardial infarction (MI) may similarly increases occurrence of AD is unknown. In the current study, we performed a MI model in wild-type and AD-prone APP/PS1 mice and assessed the development of AD in these mice. We found that MI-treated mice of both wild-type and APP/PS1 behaved poorer in a social recognition test, the Morris water maze, and the plus-maze discriminative avoidance task, compared to sham-treated controls. Mechanistically, MI significantly increased the levels of reactive oxygen species, as well as increased deposition of amyloid-β peptide aggregates and phosphorylation of tau protein in mouse brain, two signature pathological features for AD. Moreover, the microglia in the MI-mice appeared to alter polarization to a more proinflammatory phenotype. Together, our data suggest that MI may be a predisposing factor for AD development.

Is Fall Risk Systematically Evaluated in Memory Clinics? A National Survey of Practice in France

BACKGROUND

Falls are a major health problem in older persons but are still under-diagnosed and challenging to prevent. Current guidelines do not target high-risk populations, especially people living with dementia. In France, people with neurocognitive disorders are mainly referred to memory clinics (MCs).

OBJECTIVE

We aimed to survey the routine practice of physicians working in MCs regarding fall risk assessment.

METHODS

We conducted a cross-sectional survey in France from January to May 2019 among physicians working in MCs, through an anonymous online questionnaire: twenty-seven questions about the physician's background and their practice of fall risk assessment, especially use of clinical and paraclinical tools. We compared the results according to the age and the specialty of the physician.

RESULTS

We obtained 171 responses with a majority of women (60%) and geriatricians (78%). All age classes and all French regions were represented. Most of respondents (98.8%) stated that they address gait and/or falls in outpatient clinic and 95.9%in day hospitals. When asked about how they assess fall risk, fall history (83%) and gait examination (68.4%) were the most widely used, while orthostatic hypotension (24%) and clinical standardized tests (25.7%) were less common. Among standardized tests, One-leg Balance, Timed Up and Go Test, and gait speed measurements were the most used. Geriatricians had more complete fall risk assessment than neurologists (e.g., 56%versus 13%for use of standardized tests, p < 0.0001).

CONCLUSION

Almost all physicians addressed the question of fall in MC, but practices are widely heterogeneous. Further investigations are needed to standardize fall risk assessment in MCs.

Orthostatic hypotension in older people: considerations, diagnosis and management

Orthostatic hypotension (OH) is very common in older people and is encountered daily in emergency departments and medical admissions units. It is associated with a higher risk of falls, fractures, dementia and death, so prompt recognition and treatment are essential. In this review article, we describe the physiology of standing (orthostasis) and the pathophysiology of orthostatic hypotension. We focus particularly on aspects pertinent to older people. We review the evidence and consensus management guidelines for all aspects of management. We also tackle the challenge of concomitant orthostatic hypotension and supine hypertension, providing a treatment overview as well as practical suggestions for management. In summary, orthostatic hypotension (and associated supine hypertension) are common, dangerous and disabling, but adherence to simple structures management strategies can result in major improvements.

Evaluating the Real-World Representativeness of Participants with Mild Cognitive Impairment in Canadian Research Protocols: a Comparison of the Characteristics of a Memory Clinic Patients and Research Samples

Background

Studies of mild cognitive impairment (MCI) employ rigorous eligibility criteria, resulting in sampling that may not be representative of the broader clinical population.

Objective

To compare the characteristics of MCI patients in a Calgary memory clinic to those of MCI participants in published Canadian studies.

Methods

Clinic participants included 555 MCI patients from the PROspective Registry of Persons with Memory SyMPToms (PROMPT) registry in Calgary. Research participants included 4,981 individuals with MCI pooled from a systematic literature review of 112 original, English-language peer-reviewed Canadian studies. Both samples were compared on baseline sociodemographic variables, medical and psychiatric comorbidities, and cognitive performance for MCI due to Alzheimer’s disease and Parkinson’s disease.

Results

Overall, clinic patients tended to be younger, more often male, and more educated than research participants. Psychiatric disorders, traumatic brain injury, and sensory impairment were commonplace in PROMPT (up to 83% affected) but > 80% studies in the systematic review excluded these conditions. PROMPT patients also performed worse on global cognition measures than did research participants.

Conclusion

Stringent eligibility criteria in Canadian research studies excluded a considerable subset of MCI patients with comorbid medical or psychiatric conditions. This exclusion may contribute to differences in cognitive performance and outcomes compared to real-world clinical samples.

Neurogenic orthostatic hypotension impairs information processing speed and attention

Neurogenic orthostatic hypotension (NOH) is characterized by a drop in systolic blood pressure (SBP) ≥20 mmHg or diastolic blood pressure (DBP) ≥10 mmHg within three minutes of upright posture. NOH is common in the elderly population. This group of individuals is at an increased risk for deficits in multiple cognitive domains such as information processing speed (IPS) and attention. The objective of the current study was to investigate the change in IPS and attention during head-up tilt (HUT) in patients with NOH compared to controls. Cognitive function was assessed in the supine and HUT positions using the symbol digit modalities test (SDMT) which assesses IPS and the Stroop Test which measures attention. 40 participants completed the study, 20 controls (age 64.50 ± 9.25) and 20 NOH patients (age 69.55 ± 7.43) with associated conditions of Parkinson's disease (n = 11), multiple systems atrophy (n = 3), early Lewy body dementia (n = 1) and idiopathic NOH (n = 5). NOH patients had no difference in IPS between supine (43.20 ± 15.26) and HUT (42.90 ± 14.33; p = .77). Controls had significantly faster IPS in the HUT position (69.90 ± 12.02) compared to supine (63.55 ± 9.96; p < .001). NOH patients had significantly slower IPS in both the supine and HUT position compared to controls (p < .001). Attention in the HUT position was significantly worse in NOH patients (-14.86 ± 8.96) compared to controls (-8.68 ± 7.13; p = .029). During HUT, NOH patients experienced a significant decrease in mean SBP by -64.11 ± 18.96 from baseline, whereas controls only had a mean decrease of -5.69 ± 7.65. It is evident that NOH patients have impaired IPS and attention compared to controls and likely plays an important role in the morbidity of these individuals.

Orthostatic hypotension in older persons is not associated with cognitive functioning, features of cerebral damage or cerebral blood flow

OBJECTIVE

Particularly in old age, orthostatic hypotension has been related to worse cognitive functioning, possibly caused by reduced cerebral blood flow (CBF). This study investigates whether orthostatic hypotension in older people is associated with cognitive dysfunction and, if so, whether this association is mediated by cerebral vascular damage and/or decreased CBF.

METHODS

Four hundred and twenty participants of the Discontinuation of ANtihypertensive Treatment in Elderly People (DANTE) Study Leiden (mean age 81 years, all using antihypertensive medication and with mild cognitive deficits), and MRI data from 214 participants of the nested DANTE MRI sub-study. Orthostatic hypotension was defined as either a SBP decrease at least 20 mmHg and/or a DBP decrease of at least 10 mmHg within 3 min of standing up. Cognitive functioning was assessed using a battery of six cognitive tests covering global cognition, memory function, executive function and psychomotor speed. Cerebral vascular damage and CBF were assessed using MRI.

RESULTS

The prevalence of orthostatic hypotension was 47% (n = 199). Compared with the group without orthostatic hypotension, participants with orthostatic hypotension showed no differences in any of the cognitive functions, features of cerebral small vessel disease, microstructural integrity or CBF.

CONCLUSION

In this population of older persons, the presence of orthostatic hypotension was not associated with decreased cognition. In addition, no differences were found in the supposedly underlying cerebral vascular mechanisms.

[Hypotensions in the elderly: Clinical and therapeutic features]

Hypotension and especially very low diastolic blood pressure could be an at-risk situation in very old and frail patients and in those with coronary heart disease. Chronic hypotension in people with heart failure is an indicator of poor prognosis and hinders the management of therapy. Orthostatic hypotension is a decrease in blood pressure>20mmHg for systolic and/or>10mmHg for diastolic within 3minutes after transition from supine to upright. Orthostatic hypotension may be symptomatic or not. The search for orthostatic hypotension is part of the clinical examination of elderly patients with hypertension, falling, diabetes and or polymedication. First intention treatment aims to correct modifiable modifying factors and to limit the circulatory consequences of orthostatism by elastic venous compression.

Orthostatic hypotension and dementia incidence: links and implications

Orthostatic hypotension (OH) is a common condition, particularly in patients with α-synucleinopathies such as Parkinson's disease, and has a significant impact on activities of daily living and quality of life. Recent data suggest an association with cognitive impairment. Herein, we review the evidence that OH increases the odds of incident mild cognitive impairment and dementia. Potential mechanisms underlying the putative relationship are discussed, including cerebral hypoperfusion, supine hypertension, white matter hyperintensities, and neurodegeneration. Finally, we highlight the challenges with respect to treatment and the negative impact on the quality of life and long-term prognosis presented by the coexistence of OH and dementia. Large population-based studies have reported that OH is associated with about a 20% increased risk of dementia in the general population, while smaller cohort studies suggest an even greater effect in patients with α-synucleinopathies (3- to 7-fold higher than controls). Ultimately, OH exposure is difficult to quantify, predominantly limited to pressure regulation during a one-time orthostatic challenge, and the causative association with dementia may turn out to be bidirectional, especially in α-synucleinopathies. Early diagnosis and treatment of OH may improve long-term prognosis.

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

BACKGROUND

Orthostatic hypotension (OH) may negatively affect physical functioning and aggravate morbidities, but existing evidence is contradictory.

METHODS

MEDLINE (from 1946), PubMed (from 1966) and EMBASE databases (from 1947) were systematically searched for studies on the association of OH and physical functioning in older adults, categorized as: balance, gait characteristics, walking speed, Timed Up and Go time, handgrip strength (HGS), physical frailty, exercise tolerance, physical activity, activities of daily living (ADL), and performance on the Hoehn and Yahr scale (HY) and Unified Parkinson's Disease Rating Scale (UPDRS). Study quality was assessed using the Newcastle Ottawa Scale.

RESULTS

Forty-two studies were included in the systematic review (29,421 individuals) and 29 studies in the meta-analyses (23,879 individuals). Sixteen out of 42 studies reported a significant association of OH with worse physical functioning. Meta-analysis showed a significant association of OH with impaired balance, ADL performance and HY/UPDRS III performance, but not with gait characteristics, mobility, walking speed, TUG, HGS, physical frailty, exercise tolerance, physical activity and UPDRS II performance.

CONCLUSIONS

OH was associated with impaired balance, ADL performance and HY/UPDRS III performance, but not with other physical functioning categories. The results suggest that OH interventions could potentially improve some aspects of physical functioning.

Physiological changes in neurodegeneration - mechanistic insights and clinical utility

The effects of neurodegenerative syndromes extend beyond cognitive function to involve key physiological processes, including eating and metabolism, autonomic nervous system function, sleep, and motor function. Changes in these physiological processes are present in several conditions, including frontotemporal dementia, amyotrophic lateral sclerosis, Alzheimer disease and the parkinsonian plus conditions. Key neural structures that mediate physiological changes across these conditions include neuroendocrine and hypothalamic pathways, reward pathways, motor systems and the autonomic nervous system. In this Review, we highlight the key changes in physiological processing in neurodegenerative syndromes and the similarities in these changes between different progressive neurodegenerative brain conditions. The changes and similarities between disorders might provide novel insights into the human neural correlates of physiological functioning. Given the evidence that physiological changes can arise early in the neurodegenerative process, these changes could provide biomarkers to aid in the early diagnosis of neurodegenerative diseases and in treatment trials.