Cognition and chronic hypoxia in pulmonary diseases

Impact of Pneumonia on Cognitive Aging: A Longitudinal Propensity-Matched Cohort Study

BACKGROUND

Acute clinical events, such as pneumonia, may impact physical functionality but their effect on cognition and the possible duration of this effect remains to be quantified. This study investigated the impact of pneumonia on cognitive trajectories and dementia development in older people.

METHODS

Data were obtained from 60+ years old individuals, who were assessed from 2001 to 2018 in the population-based SNAC-K study (Sweden). Participants were eligible if they were not institutionalized, had no dementia, and did not experience pneumonia 5 years prior to baseline (N = 2 063). A propensity score was derived to match 1:3 participants hospitalized with a diagnosis of pneumonia (N = 178), to nonexposed participants (N = 534). Mixed linear models were used to model cognitive decline. The hazard of dementia, clinically diagnosed by physicians following Diagnostic and Statistical Manual of Mental Disorders (DSM)-IV, was estimated using Cox regression models.

RESULTS

We found a transient impact of pneumonia on cognitive decline in the first 2.5 years (B = -0.94, 95% confidence interval [CI] -1.75, -0.15). The hazard ratio (HR) for dementia was not statistically significantly increased in pneumonia participants (HR = 1.17, 95%CI 0.82, 1.66).

CONCLUSIONS

The transient impact of pneumonia on cognitive function suggests an increased need of health care for patients after a pneumonia-related hospitalization and reinforces the relevance of pneumonia prevention.

Cognitive Interventions in Individuals With Chronic Respiratory Diseases: Protocol for a Systematic Review

BACKGROUND

Chronic respiratory diseases (CRDs) may cause reduced oxygen availability to organs and body tissues, leading to an increased risk for ischemic damage, which can result in brain tissue injury. This damage can lead to a myriad of neurological symptoms contributing to cognitive decline. Cognitive interventions may attenuate cognitive deficits in people with CRDs; however, the effects have not yet been systematically summarized in the literature.

OBJECTIVE

The purpose of this systematic review is to assess the effects of cognitive interventions (including cognitive behavioral therapy and transcranial brain stimulation) on cognitive function (primary outcome), HRQL, self-management, symptoms, physical activity, physical function, ability to complete activities of daily living (ADLs), hospital admissions, functional capacity, functional performance, psychological and social outcomes, exacerbations, healthcare utilization, and survival in individuals with CRDs.

METHODS

This review will be conducted in accordance with the Cochrane handbook for systematic reviews of interventions and reported following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Searches will be performed in MEDLINE, Embase, Emcare, PsycINFO, Scopus, and CINAHL. Articles will be included if they focus on the effects of cognitive interventions on adults with CRDs, are published in peer-reviewed journals, and are written in English, French, or Portuguese. Risk of bias will be evaluated with the Cochrane Risk of Bias 2 tool for randomized controlled trials, and the Risk of Bias in Non-randomized Studies of Interventions tool for nonrandomized studies. Meta-analyses will be performed if at least 2 studies provided sufficient data for a specific outcome. The GRADE (Grading of Recommendations, Assessment, Development, and Evaluation) assessment will be used to evaluate the overall quality of the evidence.

RESULTS

This systematic review was initiated in November 2022 and registered with PROSPERO in February 2023, prior to title and abstract screening. Full-text screening of articles will be completed in June 2023. Data extraction and drafting of the manuscript will occur from July 2023 to August 2023, with expected publication in February 2024.

CONCLUSIONS

This systematic review will summarize the effects of cognitive interventions on cognitive function in people with CRDs. It will guide health care professionals in selecting evidence-based strategies to enhance cognitive well-being and overall health outcomes for individuals with CRDs. Additionally, it will identify research gaps and highlight areas for future exploration, supporting researchers in advancing knowledge in this field.

TRIAL REGISTRATION

PROSPERO CRD42023396234; https://tinyurl.com/mwjrfbxv.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

PRR1-10.2196/48235.

A Neuropsychiatric Assessment of Children with Previous SARS-CoV-2 Infection

AIM

Concerns have been raised about possible neuropsychiatric sequelae of COVID-19. The objective of this study was to examine the plausibility of long-term mental health consequences of COVID-19 by assessing a sample of children after the resolution of the acute SARS-CoV-2 infection.

METHOD

As part of a systematic follow-up assessment of pediatric patients with COVID-19 conducted at two university children's hospitals, 50 children (56% males) aged 8 to 17 years (median 11.5), 26% with previous multisystem inflammatory syndrome in children (MIS-C), without a prior history of neuropsychiatric disorders, received a battery of clinical neuropsychiatric and neuropsychological rating scales that included the Pediatric Migraine Disability Assessment (PedMIDAS), Sleep Disturbance Scale for Children (SDSC), Multidimensional Anxiety Scale for Children (MASC-2), Child Depression Inventory (CDI-2), Child Behavior Checklist (CBCL), and the NEPSY II (Neuropsychological Assessment, Second Edition). The assessments were conducted between 1 and 18 months (median 8 months) after the acute infection.

RESULTS

The CBCL internalizing symptoms score was in the clinical range for 40% of the participants (vs. a population expected rate of about 10%, p < 0.001). A sleep disturbance was detected in 28%, clinically significant anxiety in 48%, and depressive symptoms in 16%. The NEPSY II scores showed impairment in attention and other executive functions in 52%, and memory deficits in 40% of the children.

CONCLUSIONS

These data from direct assessment of a sample of children who had SARS-CoV-2 infection show higher than expected rates of neuropsychiatric symptoms, thus supporting the possibility that COVID-19 may have mental health sequelae long after the resolution of the acute infection.

Erythrocytes Functionality in SARS-CoV-2 Infection: Potential Link with Alzheimer's Disease

Coronavirus disease 2019 (COVID-19) is a rapidly spreading acute respiratory infection caused by SARS-CoV-2. The pathogenesis of the disease remains unclear. Recently, several hypotheses have emerged to explain the mechanism of interaction between SARS-CoV-2 and erythrocytes, and its negative effect on the oxygen-transport function that depends on erythrocyte metabolism, which is responsible for hemoglobin-oxygen affinity (Hb-O2 affinity). In clinical settings, the modulators of the Hb-O2 affinity are not currently measured to assess tissue oxygenation, thereby providing inadequate evaluation of erythrocyte dysfunction in the integrated oxygen-transport system. To discover more about hypoxemia/hypoxia in COVID-19 patients, this review highlights the need for further investigation of the relationship between biochemical aberrations in erythrocytes and oxygen-transport efficiency. Furthermore, patients with severe COVID-19 experience symptoms similar to Alzheimer's, suggesting that their brains have been altered in ways that increase the likelihood of Alzheimer's. Mindful of the partly assessed role of structural, metabolic abnormalities that underlie erythrocyte dysfunction in the pathophysiology of Alzheimer's disease (AD), we further summarize the available data showing that COVID-19 neurocognitive impairments most probably share similar patterns with known mechanisms of brain dysfunctions in AD. Identification of parameters responsible for erythrocyte function that vary under SARS-CoV-2 may contribute to the search for additional components of progressive and irreversible failure in the integrated oxygen-transport system leading to tissue hypoperfusion. This is particularly relevant for the older generation who experience age-related disorders of erythrocyte metabolism and are prone to AD, and provide an opportunity for new personalized therapies to control this deadly infection.

Myokines may target accelerated cognitive aging in people with spinal cord injury: A systematic and topical review

Persons with spinal cord injury (SCI) can suffer accelerated cognitive aging, even when correcting for mood and concomitant traumatic brain injury. Studies in healthy older adults have shown that myokines (i.e. factors released from muscle tissue during exercise) may improve brain health and cognitive function. Myokines may target chronic neuroinflammation, which is considered part of the mechanism of cognitive decline both in healthy older adults and SCI. An empty systematic review, registered in PROSPERO (CRD42022335873), was conducted as proof of the lack of current research on this topic in people with SCI. Pubmed, Embase, Cochrane and Web of Science were searched, resulting in 387 articles. None were considered eligible for full text screening. Hence, the effect of myokines on cognitive function following SCI warrants further investigation. An in-depth narrative review on the mechanism of SCI-related cognitive aging and the myokine-cognition link was added to substantiate our hypothetical framework. Readers are fully updated on the potential role of exercise as a treatment strategy against cognitive aging in persons with SCI.

Does peak expiratory flow moderate trajectories of cognitive function among individuals with lung diseases? A longitudinal analysis of the National Health and Aging Trends Study

INTRODUCTION

Impaired cognitive function can co-exist in chronic respiratory diseases. However, it is not clear if peak expiratory flow (PEF) impacts changes in cognitive function. Our objective was to explore whether peak expiratory flow moderates trajectories of memory, visuospatial abilities, and executive function in individuals with chronic respiratory diseases.

METHODS

This was an analysis of individuals with lung diseases from the National Health and Aging Trends Study. Multivariable-adjusted generalized linear mixed models were used to estimate trajectories of immediate and delayed recall, and clock drawing over a 10-year follow-up. The interaction between PEF and time were plotted using sex-specific values for peak expiratory flow at 10th, 50th and 90th percentiles.

RESULTS

In females, interactions of time-by-PEF were found for both immediate (n = 489, t = 2.73, p<0.01) and delayed recall (n = 489, t = 3.38, p<0.01). Females in the 10th vs. 90th percentile of PEF declined in immediate recall at 0.14 vs. 0.065 words/year, and 0.17 vs. 0.032 words/year for delayed recall. Among males, recall declined linearly over 10 years (immediate recall: n = 296, t = -3.08, p < 0.01; delayed recall: n = 292, t = -2.46, p = 0.02), with no interaction with PEF. There were no time-by-PEF interactions nor declines over time in clock drawing scores in both sexes (females: n = 484, t = 0.25, p = 0.81; males: n = 291, t = -0.61, p = 0.55).

CONCLUSION

Females with the lowest PEF values experienced the greatest rates of decline in immediate and delayed recall over 10 years of follow-up, whereas males experienced similar declines in memory outcomes across all levels of PEF. Clock drawing scores remained stable over 10 years in both sexes.

Cognitive Impairment after Post-Acute COVID-19 Infection: A Systematic Review of the Literature

The present study aims to provide a critical overview of the literature on the relationships between post-acute COVID-19 infection and cognitive impairment, highlighting the limitations and confounding factors. A systematic search of articles published from 1 January 2020 to 1 July 2022 was performed in PubMed/Medline. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Only studies using validated instruments for the assessment of cognitive impairment were included. Out of 5515 screened records, 72 studies met the inclusion criteria. The available evidence revealed the presence of impairment in executive functions, speed of processing, attention and memory in subjects recovered from COVID-19. However, several limitations of the literature reviewed should be highlighted: most studies were performed on small samples, not stratified by severity of disease and age, used as a cross-sectional or a short-term longitudinal design and provided a limited assessment of the different cognitive domains. Few studies investigated the neurobiological correlates of cognitive deficits in individuals recovered from COVID-19. Further studies with an adequate methodological design are needed for an in-depth characterization of cognitive impairment in individuals recovered from COVID-19.

Disentangling the cognitive, physical, and mental health sequelae of COVID-19

As COVID-19 cases exceed hundreds of millions globally, many survivors face cognitive challenges and prolonged symptoms. However, important questions about the cognitive effects of COVID-19 remain unresolved. In this cross-sectional online study, 478 adult volunteers who self-reported a positive test for COVID-19 (mean = 30 days since most recent test) perform significantly worse than pre-pandemic norms on cognitive measures of processing speed, reasoning, verbal, and overall performance, but not short-term memory, suggesting domain-specific deficits. Cognitive differences are even observed in participants who did not require hospitalization. Factor analysis of health- and COVID-related questionnaires reveals two clusters of symptoms—one that varies mostly with physical symptoms and illness severity, and one with mental health. Cognitive performance is positively correlated with the global measure encompassing physical symptoms, but not the one that broadly describes mental health, suggesting that the subjective experience of “long COVID” relates to physical symptoms and cognitive deficits, especially executive dysfunction.

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Survivors of COVID-19 exhibit cognitive differences in specific domains

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Speed of processing, verbal, and reasoning are affected, but not memory function

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Performance in affected domains is linked to physical but not mental health

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These effects are observed in mild and hospitalized cases of COVID-19

Respiratory Muscle Training Can Improve Cognition, Lung Function, and Diaphragmatic Thickness Fraction in Male and Non-Obese Patients with Chronic Obstructive Pulmonary Disease: A Prospective Study

Patients with chronic obstructive pulmonary disease (COPD) are frequently comorbid with mild cognitive impairment (MCI). Whether respiratory muscle training (RMT) is helpful for patients with COPD comorbid MCI remains unclear. Inspiratory muscle training (IMT) with or without expiratory muscle training (EMT) was performed. Patients were randomly assigned to the full training group (EMT + IMT) or the simple training group (IMT only). A total of 49 patients completed the eight-week course of RMT training. RMT significantly improved the maximal inspiratory pressure (MIP), the diaphragmatic thickness fraction and excursion, lung function, scores in the COPD assessment test (CAT), modified Medical Research Council (mMRC) scale scores, and MMSE. The between-group difference in the full training and single training group was not significant. Subgroup analysis classified by the forced expiratory volume in one second (FEV1) level of patients showed no significant differences in MIP, lung function, cognitive function, and walking distance. However, a significant increase in diaphragmatic thickness was found in patients with FEV1 ≥ 30%. We suggest that patients with COPD should start RMT earlier in their disease course to improve physical activity.

Altered Brain Networks in Chronic Obstructive Pulmonary Disease: An Electroencephalography Analysis

Background. Limited data are available regarding brain networks in patients with chronic obstructive pulmonary disease (COPD). Here, we investigated brain networks in COPD using graph theoretical analysis of electroencephalography data. Methods. Thirty-eight patients with COPD and 38 healthy controls underwent scalp electroencephalography. We calculated graph measures including average degree, characteristic path length, global efficiency, local efficiency, clustering coefficient, and modularity and compared them between patients and controls. Results. Average degree, global efficiency, local efficiency, and clustering coefficients were lower, while characteristic path length and modularity were higher in patients with COPD than in controls in the alpha band (P < .05). Significant differences in node degree and global node efficiency between controls and patients were mainly prominent in the medial parieto-central regions in the alpha band. Local efficiency and node clustering coefficients mainly differed in the occipito-parietal regions in the alpha band. We observed no differences in nodal measures in the delta, theta, beta, and gamma bands and no relationships between pulmonary function test parameters and global measures in any frequency bands. Conclusions. The thalamus generates alpha activity and is responsible for controlling respiratory activities to maintain oxygen delivery to tissues in response to chronic hypoxia. We thus speculate that our findings might be related to exposure to chronic hypoxia, implicated in the pathophysiological mechanisms underlying cognitive deficits in patients with COPD. Graph theoretical analysis of resting-state electroencephalography could be considered as a quantitative framework to understand functional networks in COPD.

Neurological effects of respiratory dysfunction

The respiratory and the nervous systems are closely interconnected and are maintained in a fine balance. Central mechanisms maintain strict control of ventilation due to the high metabolic demands of brain which depends on a continuous supply of oxygenated blood along with glucose. Moreover, brain perfusion is highly sensitive to changes in the partial pressures of carbon dioxide and oxygen in blood, which in turn depend on respiratory function. Ventilatory control is strictly monitored and regulated by the central nervous system through central and peripheral chemoreceptors, baroreceptors, the cardiovascular system, and the autonomic nervous system. Disruption in this delicate control of respiratory function can have subtle to devastating neurological effects as a result of ensuing hypoxia or hypercapnia. In addition, pulmonary circulation receives entire cardiac output and this may act as a conduit to transmit infections and also for metastasis of malignancies to brain resulting in neurological dysfunction. Furthermore, many neurological paraneoplastic syndromes can have underlying lung malignancies resulting in respiratory dysfunction. It is essential to understand the underlying mechanisms and the resulting manifestations in order to prevent and effectively manage the many neurological effects of respiratory dysfunction. This chapter explores the various neurological effects of respiratory dysfunction with focus on their pathophysiology, etiologies, clinical features and long-term neurological sequelae.

Neurological Manifestations in COVID-19: An Unrecognized Crisis in Our Elderly?

As of December 2020, there were more than 900,000 COVID-19 hospitalizations in the US with about 414,000 among individuals aged 65 years and older. Recent evidence suggests a growing number of older patients continue to suffer serious neurological comorbidities including polyneuropathy, cerebrovascular disease, central nervous system infection, cognitive deficits, and fatigue following discharge. Studies suggest that complaints manifest late in disease and persist beyond resolution of acute COVID-19 symptoms. Recent research reports that neurocognitive symptoms are correlated with severe disease, older age, male gender, and comorbidities including hypertension, renal failure, and neoplastic disease. The underlying causes are unclear, but current hypotheses include hypoxic-ischemic brain injury, immunopathological mechanisms, and neurotropism of SARS-CoV-2 infection. There is a pressing need for more research into the underlying mechanisms of post-COVID-19 neurological sequela, particularly in the elderly, a population already burdened with neurocognitive disorders.

Cerebral Hypoxia: Its Role in Age-Related Chronic and Acute Cognitive Dysfunction

Postoperative cognitive dysfunction (POCD) has been reported with widely varying frequency but appears to be strongly associated with aging. Outside of the surgical arena, chronic and acute cerebral hypoxia may exist as a result of respiratory, cardiovascular, or anemic conditions. Hypoxia has been extensively implicated in cognitive impairment. Furthermore, disease states associated with hypoxia both accompany and progress with aging. Perioperative cerebral hypoxia is likely underdiagnosed, and its contribution to POCD is underappreciated. Herein, we discuss the various disease processes and forms in which hypoxia may contribute to POCD. Furthermore, we outline hypoxia-related mechanisms, such as hypoxia-inducible factor activation, cerebral ischemia, cerebrovascular reserve, excitotoxicity, and neuroinflammation, which may contribute to cognitive impairment and how these mechanisms interact with aging. Finally, we discuss opportunities to prevent and manage POCD related to hypoxia.

Lung Function Impairment and the Risk of Incident Dementia: The Rotterdam Study

BACKGROUND

The etiology of dementia may partly be underpinned by impaired lung function via systemic inflammation and hypoxia.

OBJECTIVE

To prospectively examine the association between chronic obstructive pulmonary disease (COPD) and subclinical impairments in lung function and the risk of dementia.

METHODS

In the Rotterdam Study, we assessed the risk of incident dementia in participants with Preserved Ratio Impaired Spirometry (PRISm; FEV1/FVC≥0.7, FEV1 < 80% predicted) and in participants with COPD (FEV1/FVC < 0.7) compared to those with normal spirometry (controls; FEV1/FVC≥0.7, FEV1≥80% predicted). Hazard ratios (HRs) with 95% confidence intervals (CI) for dementia were adjusted for age, sex, education attainment, smoking status, systolic blood pressure, body mass index, triglycerides, comorbidities and Apolipoprotein E (APOE) genotype.

RESULTS

Of 4,765 participants, 110 (2.3%) developed dementia after 3.3 years. Compared to controls, participants with PRISm, but not COPD, had an increased risk for all-type dementia (adjusted HRPRISm 2.70; 95% CI, 1.53-4.75; adjusted HRCOPD 1.03; 95% CI, 0.61-1.74). These findings were primarily driven by men and smokers. Similarly, participants with FVC% predicted values in the lowest quartile compared to those in the highest quartile were at increased risk of all-type dementia (adjusted HR 2.28; 95% CI, 1.31-3.98), as well as Alzheimer's disease (AD; adjusted HR 2.13; 95% CI, 1.13-4.02).

CONCLUSION

Participants with PRISm or a low FVC% predicted lung function were at increased risk of dementia, compared to those with normal spirometry or a higher FVC% predicted, respectively. Further research is needed to elucidate whether this association is causal and how PRISm might contribute to dementia pathogenesis.

Neuropsychological functioning in patients with interstitial lung disease

OBJECTIVE

We undertook the present study to investigate the cognitive status of patients with interstitial lung disease (ILD) and its relationship to pulmonary function and cardiovascular efficiency.

METHOD

Fifty-one patients with a diagnosis of ILD [mean duration = 3.13 years (SD = 3.01)] received a respiratory examination, including spirometry and the six-minute walk test, and completed a neuropsychological assessment including several cognitive domains. Eighty-eight healthy individuals matched on age, education, and gender, completed the neuropsychological test battery.

RESULTS

Patients performed more poorly than their healthy peers on cognitive tasks related to verbal and visual memory, visual perception, and working memory, but not attention, processing speed and executive functioning. Stepwise linear regression analyses showed that exercise-related measures (heart rate, oxygen saturation and distance walked) predicted performance on neuropsychological tests of psychomotor speed, verbal memory and word production. Additionally, an index of pulmonary function, specifically, lung diffusion capacity, predicted performance on selective and sustained attention and word generation.

CONCLUSION

The present preliminary findings may have implications for the quality of life and treatment compliance of patients with ILD and warrant further study with a larger sample of patients.

Cognitive profile following COVID-19 infection: Clinical predictors leading to neuropsychological impairment

BACKGROUND

Cognitive manifestations associated with the severity of a novel coronavirus (COVID-19) infection are unknown. An early detection of neuropsychological manifestations could modify the risk of subsequent irreversible impairment and further neurocognitive decline.

METHODS

In our single-center cohort study, we included all consecutive adult patients, aged between 20 and 60 years old with confirmed COVID-19 infection. Neuropsychological assessment was performed by the same trained neuropsychologist from April, 22nd through June 16th, 2020. Patients with previous known cognitive impairment, any central nervous system or psychiatric disease were excluded. Demographic, clinical, pharmacological and laboratory data were extracted from medical records.

RESULTS

Thirty-five patients met inclusion criteria and were included in the study. Patients presenting headache, anosmia, dysgeusia, diarrhea and those who required oxygen therapy had lower scores in memory, attention and executive function subtests as compared to asymptomatic patients. Patients with headache and clinical hypoxia scored lower in the global Cognitive Index (P ​= ​0.002, P ​= ​0.010). A T score lower than 30 was observed in memory domains, attention and semantic fluency (2 [5.7%]) in working memory and mental flexibility (3 [8.6%]) and in phonetic fluency (4 [11.4%]). Higher scores in anxiety and depression (P ​= ​0.047, P ​= ​0.008) were found in patients with cognitive complaints.

CONCLUSIONS

In our cohort of COVID-19 patients neurologic manifestations were frequent, including cognitive impairment. Neurological symptoms during infection, diarrhea and oxygen therapy were risk factors for neurocognitive impairment. Cognitive complaints were associated with anxiety and depression.

Oxygen: The Rate-Limiting Factor for Episodic Memory Performance, Even in Healthy Young Individuals

Cognition is a crucial element of human functionality. Like any other physical capability, cognition is both enabled and limited by tissue biology. The aim of this study was to investigate whether oxygen is a rate-limiting factor for any of the main cognitive domains in healthy young individuals. Fifty-six subjects were randomly assigned to either increased oxygen supply using hyperbaric oxygen (two atmospheres of 100% oxygen) or to a “sham” treatment (a simulation of increased pressure in a chamber with normal air). While in the chamber, participants went through a battery of tests evaluating the major cognitive domains including information processing speed, episodic memory, working memory, cognitive flexibility, and attention. The results demonstrated that from all evaluated cognitive domains, a statistically significant improvement was found in the episodic memory of the hyper-oxygenized group. The hyper-oxygenized group demonstrated a better learning curve and a higher resilience to interference. To conclude, oxygen delivery is a rate-limiting factor for memory function even in healthy young individuals under normal conditions. Understanding the biological limitations of our cognitive functions is important for future development of interventional tools that can be used in daily clinical practice.

Cognitive Dysfunction in Persons with Chronic Spinal Cord Injuries

Cognitive dysfunction (CD) is pervasive in individuals who have chronic spinal cord injuries (SCI). Although classically associated with concomitant traumatic brain injuries, many other causes have been proposed, including premorbid neuropsychological conditions, mood disorders, substance abuse, polypharmacy, chronic pain and fatigue, sleep apnea, autonomic dysregulation, post-intensive care unit syndrome, cortical reorganizations, and neuroinflammation. The consequences of CD are likely widespread, affecting rehabilitation and function. CD in those with SCI should be recognized, and potentially treated, in order to provide the best patient care.

Risk factors of chronic obstructive pulmonary disease exacerbations

Chronic Obstructive Pulmonary Disease (COPD) is a chronic respiratory disease characterised by persistent respiratory symptoms and airflow limitation. COPD has a major impact on public health, mainly because of its increasing prevalence, morbidity and mortality. The natural course of COPD is aggravated by episodes of respiratory symptom worsening termed exacerbations that contribute to disease progression. Acute Exacerbations of COPD (AECOPD) can be triggered by a multitude of different factors, including respiratory tract infections, various exposures, prior exacerbations, non-adherence to treatment and associated comorbidities. AECOPD are associated with an inexorable decline of lung function and a significantly worse survival outcome. This review will summarise the most important aspects regarding the impact of different factors that contribute to COPD exacerbations.

Cognitive deficits in obstructive sleep apnea: Insights from a meta-review and comparison with deficits observed in COPD, insomnia, and sleep deprivation

Obstructive sleep apnea (OSA) is a nocturnal breathing disorder that is associated with cognitive impairment. The primary determinants of cognitive deficits in OSA are thought to be sleep disruption and blood gas abnormalities. Cognitive impairment is also seen in other disorders that are characterised primarily by sleep disturbance (e.g., sleep restriction/deprivation, insomnia) or hypoxia/hypercarbia (e.g., chronic obstructive pulmonary disease (COPD)). Assessment of the cognitive deficits observed in these other disorders could help better define the mechanisms underlying cognitive deficits in OSA. This study utilised meta-review methodology to examine the findings from systematic reviews and meta-analyses of the effects of untreated OSA, COPD, insomnia, and sleep deprivation on cognitive function in adults, compared with norms or controls. Eighteen papers met inclusion criteria: seven in OSA, two in insomnia, five in COPD, and four in sleep deprivation. OSA and COPD were both accompanied by deficits in attention, memory, executive function, psychomotor function, and language abilities, suggesting that hypoxia/hypercarbia may be an important determinant of deficits in these domains in OSA. Both OSA and sleep deprivation studies were accompanied by deficits in attention and memory, suggesting that short-term sleep disturbance in OSA may contribute to deficits in these domains. Visuospatial deficits were unique to OSA, suggesting the contribution of a mechanism other than sleep disturbance and hypoxia/hypercarbia to this problem. Our findings suggest that the cognitive deficits associated with untreated OSA are multidimensional, with different physiological disturbances responsible for differing cognitive problems.

Cognitive impairment in chronic obstructive pulmonary disease

BACKGROUND/PURPOSE

Chronic obstructive pulmonary disease (COPD), especially in severe forms, is commonly associated with multiple cognitive problems. Montreal Cognitive Assessment test (MoCA) is used to detect cognitive impairment evaluating several areas: visuospatial, memory, attention and fluency. Our study aim was to evaluate the impact of stable COPD and exacerbation (AECOPD) phases on cognitive status using MoCA questionnaire.

METHODS

We enrolled 39 patients (pts), smokers with COPD group D (30 stable and 9 in AECOPD) and 13 healthy subjects (control group), having similar level of education and no significant differences regarding the anthropometric measurements. We analyzed the differences in MoCA score between these three groups and also the correlation between this score and inflammatory markers.

RESULTS

Patients with AECOPD had a significant (p<0.001) decreased MoCA score (14.6±3.4) compared to stable COPD (20.2±2.4) and controls (24.2±5.8). The differences between groups were more accentuated for the language abstraction and attention (p<0.001) and delayed recall and orientation (p<0.001) sub-topics. No significant variance of score was observed between groups regarding visuospatial and naming score (p = 0.095). The MoCA score was significantly correlated with forced expiratory volume (r = 0.28) and reverse correlated with C-reactive protein (CRP) (r = -0.57), fibrinogen (r = -0.58), erythrocyte sedimentation rate (ESR) (r = -0.55) and with the partial pressure of CO2 (r = -0.47).

CONCLUSIONS

According to this study, COPD significantly decreases the cognitive status in advanced and acute stages of the disease.

Effects of chronic obstructive pulmonary disease and obstructive sleep apnea on cognitive functions: evidence for a common nature

Patients with chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea syndrome (OSAS) show similar neurocognitive impairments. Effects are more apparent in severe cases, whereas in moderate and mild cases the effects are equivocal. The exact mechanism that causes cognitive dysfunctions in both diseases is still unknown and only suggestions have been made for each disease separately. The primary objective of this review is to present COPD and OSAS impact on cognitive functions. Secondly, it aims to examine the potential mechanisms by which COPD and OSAS can be linked and provide evidence for a common nature that affects cognitive functions in both diseases. Patients with COPD and OSAS compared to normal distribution show significant deficits in the cognitive abilities of attention, psychomotor speed, memory and learning, visuospatial and constructional abilities, executive skills, and language. The severity of these deficits in OSAS seems to correlate with the physiological events such as sleep defragmentation, apnea/hypopnea index, and hypoxemia, whereas cognitive impairments in COPD are associated with hypoventilation, hypoxemia, and hypercapnia. These factors as well as vascocerebral diseases and changes in systemic hemodynamic seem to act in an intermingling and synergistic way on the cause of cognitive dysfunctions in both diseases. However, low blood oxygen pressure seems to be the dominant factor that contributes to the presence of cognitive deficits in both COPD and OSAS.

Mental and physical activities delay cognitive decline in older persons with dementia

OBJECTIVES

To examine the effects of cognitive stimulation (mahjong) and physical exercise (tai chi [TC]) on cognitive performance in persons with dementia.

DESIGN

Cluster-randomized open-label controlled design.

SETTING

Nursing homes.

PARTICIPANTS

One hundred ten residents, most of whom were cholinesterase-inhibitor naive. Inclusion criteria were Mini-Mental State Examination (MMSE) = 10-24 and suffering from at least very mild dementia (Clinical Dementia Rating ≥ 0.5). Exclusion criteria were being bedbound, audio/visual impairment, regular activity participation before study, or contraindications for physical or group activities.

INTERVENTIONS

Homes were randomized into three conditions (mahjong, TC, and simple handicrafts [control]). Activities were conducted three times weekly for 12 weeks.

MEASUREMENTS

Primary outcome was MMSE. Secondary outcomes were immediate/delayed recall, categorical fluency, and digit span. Various biological risk factors, including apolipoprotein E ε4 allele, were included as covariates. Measures were collected at 0 (baseline), 3 (posttreatment), 6, and 9 months.

RESULTS

Intent-to-treat analyses were performed using mixed-effects regression. Mahjong's effect varied by time for MMSE, delayed recall, and forward digit span. TC had similar effects but not for delayed recall. The typical pattern was that control participants deteriorated while mahjong and TC participants maintained their abilities over time, leading to enlarged treatment effects as time progressed. By 9 months, mahjong and TC differed from control by 4.5 points (95% confidence interval: 2.0-6.9; d = 0.48) and 3.7 points (95% confidence interval: 1.4-6.0; d = 0.40), respectively, on MMSE. No treatment effects were observed for immediate recall and backward digit span.

CONCLUSIONS

Mahjong and TC can preserve functioning or delay decline in certain cognitive domains, even in those with significant cognitive impairment.

Association of chronic obstructive pulmonary disease with cognitive decline in very elderly men

Aim

To determine the change in cognitive function in very elderly men with chronic obstructive pulmonary disease (COPD) over a 3-year period relative to age-and education-matched controls.

Methods

In this hospital-based, prospective case-control study, we evaluated a consecutive series of 110 very elderly men with COPD and 110 control subjects who were hospitalized between January and December 2007. All the subjects performed cognitive tests at baseline and underwent annual evaluations (for 3 years), which included the Mini-Mental State Examination, word list recall, delayed recall, animal category fluency, and the symbol digit modalities test.

Results

In mixed-effects models adjusted for hypertension and coronary heart disease, COPD was associated with a more rapid rate of cognitive decline based on the Mini-Mental State Examination, word list recall, delayed recall, animal category fluency, and the symbol digit modalities test (all p < 0.01) compared to controls.

Conclusion

COPD is associated with a more rapid rate of cognitive decline in very elderly persons.