The relationship between cognitive function and arterial partial pressure O2 in patients with COPD: A meta-analysis

Evaluation of wakefulness electroencephalogram in OSA patients

OBJECTIVE

Obstructive sleep apnea (OSA) has been associated with an elevated cardiovascular risk, increased daytime sleepiness, cognitive decline, and slower electroencephalographic activity (EEG). This study assesses EEG patterns during wakefulness in OSA patients compared to those without sleep-disordered breathing.

MATERIALS AND METHODS

This retrospective study analyzed 30 OSA patients with an Apnea/Hypopnea Index (AHI) of 15 or higher, as well as 29 individuals without sleep-disordered breathing (AHI of 5 or lower) who underwent hospital polysomnography and met all inclusion criteria. Sociodemographic and EEG data were obtained from the sleep laboratory database. Blinded EEG analysis was conducted by two observers, assessing activity in the frontal, central, and occipital regions.

RESULTS

No significant differences were observed in EEG activity between OSA and non-OSA patients. However, a weak correlation was found between decreased C3 EEG frequency and higher AHI (p = 0.033), as well as increased total sleep time and higher O2 EEG frequency (p = 0.038). Lower amplitudes in C3 (p = 0.043) and O1 (p = 0.031) were correlated with reduced average oxygen saturation.

CONCLUSION

Our findings suggest that OSA-related hypoxemia may impact neuronal activity, highlighting the need to address this sleep-disordered breathing in order to potentially prevent the cognitive decline observed in OSA patients.

Interactions between Cognitive, Affective, and Respiratory Profiles in Chronic Respiratory Disorders: A Cluster Analysis Approach

This study conducted at Leamna Pulmonology Hospital investigated the interrelations among cognitive, affective, and respiratory variables within a cohort of 100 patients diagnosed with chronic respiratory conditions, utilizing sophisticated machine learning-based clustering techniques. Spanning from October 2022 to February 2023, hospitalized individuals confirmed to have asthma or COPD underwent extensive evaluations using standardized instruments such as the mMRC scale, the CAT test, and spirometry. Complementary cognitive and affective assessments were performed employing the MMSE, MoCA, and the Hamilton Anxiety and Depression Scale, furnishing a holistic view of patient health statuses. The analysis delineated three distinct clusters: Moderate Cognitive Respiratory, Severe Cognitive Respiratory, and Stable Cognitive Respiratory, each characterized by unique profiles that underscore the necessity for tailored therapeutic strategies. These clusters exhibited significant correlations between the severity of respiratory symptoms and their effects on cognitive and affective conditions. The results highlight the benefits of an integrated treatment approach for COPD and asthma, which is personalized based on the intricate patterns identified through clustering. Such a strategy promises to enhance the management of these diseases, potentially elevating the quality of life and everyday functionality of the patients. These findings advocate for treatment customization according to the specific interplays among cognitive, affective, and respiratory dimensions, presenting substantial prospects for clinical advancement and pioneering new avenues for research in the domain of chronic respiratory disease management.

Common and distinct risk factors that influence more severe and distressing shortness of breath profiles in oncology outpatients

BACKGROUND

Shortness of breath occurs in 10%-70% of oncology patients. Very little is known about interindividual variability in its severity and distress and associated risk factors. Using latent profile analyses (LPAs), purpose was to identify subgroups of patients with distinct severity and distress profiles for shortness of breath as single symptom dimensions. In addition, a joint LPA was done using patients' severity AND distress ratings. For each of the three LPAs, differences among the shortness of breath classes in demographic, clinical, symptom, stress, and resilience characteristics were evaluated.

METHODS

Patients completed ratings of severity and distress from shortness of breath a total of six times over two cycles of chemotherapy. All of the other measures were completed at enrollment (i.e., prior to the second or third cycle of chemotherapy). Separate LPAs were done using ratings of severity and distress, as well as a joint analysis using severity AND distress ratings. Differences among the latent classes were evaluated using parametric and nonparametric tests.

RESULTS

For severity, two classes were identified (Slight to Moderate [91.6%] and Moderate to Severe [8.4%]). For distress, two classes were identified (A Little Bit to Somewhat [83.9%] and Somewhat to Quite a Bit [16.1%]). For the joint LPA, two classes were identified (Lower Severity and Distress [79.9%] and Higher Severity and Distress [20.1%]). While distinct risk factors were associated with each of the LPAs, across the three LPAs, the common risk factors associated with membership in the worse class included: a past or current history of smoking, poorer functional status, and higher comorbidity burden. In addition, these patients had a higher symptom burden and higher levels of cancer-specific stress.

CONCLUSIONS

Clinicians can use the information provided in this study to identify high-risk patients and develop individualized interventions.

Effects of long-term oxygen therapy on the mental state of patients with chronic obstructive pulmonary disease: A systematic review

OBJECTIVES

This systematic review aimed to examine the effects of long-term oxygen therapy on the mental state of patients with chronic obstructive pulmonary disease.

METHODS

Web of Science, Medline, CINAHL, EMBASE, ProQuest, and Cochrane Library were selected to search for relevant studies. We followed the Cochrane Handbook for Systematic Reviews of Interventions, adopted the Cochrane risk-of-bias tool and Risk Of Bias In Non-randomized Studies of Interventions tool, and synthesized the outcomes narratively with Grading of Recommendations, Assessment, Development and Evaluations evidence profile.

RESULTS

Six studies were included. Moderate quality of evidence supported no effects of long-term oxygen therapy on the mental state in patients with severe resting hypoxemia and moderate resting hypoxemia (or exertional desaturation) at follow-up of 6 to 12 months; however, adverse effects on mental state among patients with moderate resting or exertional desaturation were reported at the follow-up of 36 to 48 months.

DISCUSSION

Nurses should focus on the mental state of patients treated with long-term oxygen therapy, especially those who use it for a prolonged time. Due to ethical constraints in this study, a quasi-experimental study with faithful consideration of internal validity can be commenced in the future.

Comorbid Cognitive Impairment in Chronic Obstructive Pulmonary Disease (COPD): Current Understanding, Risk Factors, Implications for Clinical Practice, and Suggested Interventions

Cognitive impairment is a common comorbidity in patients with COPD, significantly impacting health and clinical outcomes. Yet it remains under investigated and is largely overlooked. Although the exact cause of cognitive impairment in patients with COPD is still unclear, factors such as hypoxemia, vascular disease, smoking, exacerbation, and physical inactivity have been suggested. While international guidelines recommend identifying comorbidity in patients with COPD, such as cognitive impairment, cognitive assessment is not yet part of the routine assessment. Unidentified cognitive deficits in patients with COPD may have severe impacts on clinical management, resulting in an inability to maintain functional independence, poor self-management, and a greater dropout from pulmonary rehabilitation programs. There is a need to consider cognitive screening as a part of COPD assessment to promote early detection of cognitive impairment. Recognizing cognitive impairment early in the course of the illness allows the development of individualized interventions to meet patients' needs and improve clinical outcomes. Pulmonary rehabilitation should be tailored to cognitively impaired patients with COPD to maximize the benefits and minimize the incompletion rate.

The association between total cholesterol and cognitive impairment in chronic obstructive pulmonary disease patients

AIM

Chronic obstructive pulmonary disease (COPD) is primarily a respiratory system disorder associated with extrapulmonary conditions. Cognitive impairment (CoI) is very common among COPD patients This study sought to investigate the association between CoI and clinical parameters, inflammatory markers and lipid profiles in a COPD patient population.

METHODS

The study population included 111 stable COPD patients. COPD was diagnosed according to Global Initiative for Chronic Obstructive Lung Disease guideline. Total complete blood count test and biochemical measurements including lipid profile were performed. Afterwards, all patients underwent neuropsychological assessment including Hospital Anxiety and Depression Scale (HADS), Pittsburgh Sleep Quality Index and Montreal Cognitive Assessment (MoCA) tests.

RESULTS

The patients were categorized into two groups according to their MoCA test score: MoCA score ≤ 21 (CoI) (n = 69) and MoCA score > 21 (normal cognition) (n = 42). Total cholesterol (TC) levels were significantly lower in patients with CoI compared to patients with normal cognition. Inflammation related parameters including C-reactive protein were similar among groups. Multivariate logistic regression analysis yielded education, HADS score and TC (OR:1.02, 95% CI:1.00-1.04, p = 0.025) as independent predictors of MoCA score.

CONCLUSION

TC independently associates with CoI in COPD patients. There is comparable inflammatory status in COPD patients with CoI compared to COPD patients with normal cognition.

Cognitive Impairment and Its Associated Factors in Older Adults Living in High and Low Altitude Areas: A Comparative Study

BACKGROUND

Cognitive impairment is a major health concern in older adults. Few studies have examined the association between environmental factors and cognitive impairment, especially in high altitude areas. In this study, the prevalence of cognitive impairment in older adults living in high altitude was compared with those living in low altitude areas.

METHODS

This was a comparative study conducted at Qinghai (high altitude group), and Guangzhou (low altitude group), China. Cognition, depressive symptoms and quality of life (QOL) were assessed using the Montreal Cognitive Assessment (MoCA), Patient Health Questionnaire (PHQ-9) and WHO Quality of Life brief version-WHOQOL-BREF, respectively.

RESULTS

Altogether, 644 older adults (207 in Qinghai and 437 in Guangzhou) completed the assessment. The prevalence rate of cognitive impairment was 94.7% (95% CI: 91.6-97.7%) in older adults living in the high altitude area, while the corresponding figure was 89.2% (95% CI: 86.3-92.1%) in the low altitude area. After controlling for covariates, the high altitude group appeared more likely to have cognitive impairment (OR = 2.92, 95% CI: 1.23-6.91, P = 0.015) compared with the low altitude group. Within the high altitude group sample, multinomial logistic regression analysis revealed that older age (aged 74 and above) was significantly associated with higher risk of severe cognitive impairment (OR = 3.58, 95%CI: 1.44-8.93, P = 0.006), while higher education level (secondary school and above) was associated with decreased risk of moderate cognitive impairment (OR = 0.43, 95%CI: 0.22-0.85, P = 0.006). Within the high altitude group, QOL did not differ significantly between normal/mild, moderate and severe cognitive impairment subgroups across physical [F _{(1, 207)} = 1.83, P = 0.163], psychological [F _{(1, 207)} = 1.50, P = 0.225], social [F _(1,207) = 2.22, P = 0.111] and environmental domains [F _(1,207) = 0.49, P = 0.614].

CONCLUSION

This study found that cognitive impairment was more common among older adults living in the high altitude area. Regular screening and appropriate interventions should be provided to older adults in need.

Cognitive impairment caused by hypoxia: from clinical evidences to molecular mechanisms

Hypoxia is a state of reduced oxygen supply and excessive oxygen consumption. According to the duration of hypoxic period, it can be classified as acute and chronic hypoxia. Both acute and chronic hypoxia could induce abundant neurological deficits. Although there have been significant advances in the pathophysiological injuries, few studies have focused on the cognitive dysfunction. In this review, we focused on the clinical evidences and molecular mechanisms of cognitive impairment under acute and chronic hypoxia. Hypoxia can impair several cognitive domains such as attention, learning and memory, procession speed and executive function, which are similar in acute and chronic hypoxia. The severity of cognitive deficit correlates with the duration and degree of hypoxia. Recovery can be achieved after acute hypoxia, while sequelae or even dementia can be observed after chronic hypoxia, perhaps due to the different molecular mechanisms. Cardiopulmonary compensatory response, glycolysis, oxidative stress, calcium overload, adenosine, mitochondrial disruption, inflammation and excitotoxicity contribute to the molecular mechanisms of cognitive deficit after acute hypoxia. During the chronic stage of hypoxia, different adaptive responses, impaired neurovascular coupling, apoptosis, transcription factors-mediated inflammation, as well as Aβ accumulation and tau phosphorylation account for the neurocognitive deficit. Moreover, brain structural changes with hippocampus and cortex atrophy, ventricle enlargement, senile plaque and neurofibrillary tangle deposition can be observed under chronic hypoxia rather than acute hypoxia.

Lung function, COPD and cognitive function: a multivariable and two sample Mendelian randomization study

BACKGROUND

Observational studies show an association between reduced lung function and impaired cognition. Cognitive dysfunction influences important health outcomes and is a precursor to dementia, but treatments options are currently very limited. Attention has therefore focused on identifying modifiable risk factors to prevent cognitive decline and preserve cognition. Our objective was to determine if lung function or risk of COPD causes reduced cognitive function using Mendelian randomization (MR).

METHODS

Single nucleotide polymorphisms from genome wide association studies of lung function and COPD were used as exposures. We examined their effect on general cognitive function in a sample of 132,452 individuals. We then performed multivariable MR (MVMR), examining the effect of lung function before and after conditioning for covariates.

RESULTS

We found only weak evidence that reduced lung function (Beta - 0.002 (SE 0.02), p-value 0.86) or increased liability to COPD (- 0.008 (0.008), p-value 0.35) causes lower cognitive function. MVMR found both reduced FEV1 and FVC do cause lower cognitive function, but that after conditioning for height (- 0.03 (0.03), p-value 0.29 and - 0.01 (0.03) p-value 0.62, for FEV1 and FVC respectively) and educational attainment (- 0.03 (0.03) p-value 0.33 and - 0.01 (0.02), p-value 0.35) the evidence became weak.

CONCLUSION

We did not find evidence that reduced lung function or COPD causes reduced cognitive function. Previous observational studies are probably affected by residual confounding. Research efforts should focus on shared risk factors for reduced lung function and cognition, rather than lung function alone as a modifiable risk factor.

Effect of nutritional risk on cognitive function in patients with chronic obstructive pulmonary disease

Objective

We aimed to clarify the cognitive function of patients with chronic obstructive pulmonary disease (COPD) and different nutritional status.

Methods

Among 95 patients with COPD in this retrospective study, we administered the Nutritional Risk Screening 2002 (NRS 2002) and Mini-Mental State Examination (MMSE). We recorded patients’ clinical characteristics, comorbidities, and laboratory measurements. According to NRS 2002 scores, patients were divided into two groups: no nutritional risk with NRS 2002 < 3 (n = 54) and nutritional risk, with NRS 2002 ≥ 3 (n = 41).

Results

We found a negative correlation between NRS 2002 and MMSE scores in participants with COPD (r = −0.313). Patients with nutritional risk were more likely to be cognitively impaired than those with no nutritional risk. Multivariate logistic regression analysis indicated that malnutrition was an independent risk factor for cognitive impairment, after adjusting for confounders (odds ratio [OR] = 4.120, 95% confidence interval [CI]: 1.072–15.837). We found a similar association between NRS 2002 and MMSE scores at 90-day follow-up using a Pearson’s correlation test (r = −0.493) and logistic regression analysis (OR = 7.333, 95% CI: 1.114–48.264).

Conclusions

Patients with COPD at nutritional risk are more likely to have cognitive impairment.

Potential for Cognitive Communication Impairment in COVID-19 Survivors: A Call to Action for Speech-Language Pathologists

Purpose Severe acute respiratory syndrome coronavirus 2 is the virus resulting in COVID-19 infections in nearly 4.3 million Americans with COVID-19 in the United States as of July 29, 2020, with nearly 150,000 deaths and hundreds of thousands of survivors (https://www.coronavirus.jhu.edu/map.html). This tutorial reviews (a) what has been reported about neurological insults in cases of COVID-19 infection, (b) what is known from similar conditions in other disorders, and (c) how that combined information can inform clinical decision making. Method PubMed and the Cochrane Central Register of Controlled Trials were searched for COVID-19 or other coronavirus infections, cognitive impairment observed following critical care, and disorders for which intermittent or chronic hypoxia is characteristic. These were combined with searches relating to cognition, brain, and communication. All searches were conducted between April 8 and May 23, 2020. Meta-analyses and randomized clinical trials addressing other critical illnesses were also included to extend findings to potential cognitive communication outcomes following COVID-19. Results COVID-19 infection results in a combination of (a) respiratory infection with mechanical ventilation secondary to inadequate oxygenation, (b) inflammatory system reactivity, and (c) increased blood clotting factors. These affect central nervous system function incurring long-term cognitive communication impairment in a proportion of survivors. Diagnostic and intervention approaches for such impairments are discussed. Conclusions The existing literature on cognitive sequela of COVID-19 infection is small to date, but much can be learned from similar viral infections and disorders. Although COVID-19 is novel, the speech-language pathology approaches to evaluation and intervention of other populations of critical care patients are applicable. However, speech-language pathologists have not routinely been involved in these patients' acute care. As such, this is a call to action to speech-language pathologists to address the unprecedented numbers of patients who will need their services early in the disease process and throughout recovery.

Effect of 12-week pulmonary rehabilitation on cognitive function in patients with stable chronic obstructive pulmonary disease: study protocol for a single-center randomised controlled trial

INTRODUCTION

Cognitive impairment, an important complication in patients with chronic obstructive pulmonary disease (COPD), seriously affects self-management of the disease and quality of life (QoL). As an exercise-based intervention programme, pulmonary rehabilitation (PR)-especially aerobic exercise (mainly mind-body exercise) and resistance exercise (RE)-has been proposed for its potential effectiveness in improving cognitive function. However, there is still a lack of strong evidence for PR's effectiveness. In this study, we expect to clarify the effects of pulmonary-based Qigong exercise and elastic band-based RE on cognitive function in patients with COPD and to fill in the relevant evidence blanks.

METHODS AND ANALYSIS

This study is a single-centre randomised controlled trial with assessor and data analyst blinding. We will recruit 108 participants with stable COPD starting on 23 December 2019, and randomly allocate them into the pulmonary-based Qigong exercise group, elastic band-based RE group, pulmonary-based Qigong exercise and elastic band-based RE combined group, or control group at a 1:1:1:1 ratio. Participants in intervention groups will perform 30 min of exercise two times per day, 5 days a week, for 12 weeks. The primary outcome will be the global cognitive function as assessed by the Montreal Cognitive Assessment and auditory event-related potential P300. Secondary outcomes will include the specific cognitive domains-attention, memory, executive function, verbal fluency and mental-processing speed; psychological functions and QoL. Exploratory outcomes will include grey matter volume and levels of inflammatory mediators. Outcomes will be measured before and after the interventions.

ETHICS AND DISSEMINATION

Ethics approval has been granted by the Ethics Committee of Yue-Yang Integrative Medicine Hospital, an affiliate of Shanghai University of Traditional Chinese Medicine, Shanghai, China (Grant No. 2019-141). Written informed consent will be obtained from each participant before any procedures are performed. The findings will be published in peer-reviewed journals and presented at academic conferences.

TRIAL REGISTRATION NUMBER

ChiCTR1900026869; pre-results.

Carotid Artery Stiffness is Associated With Cognitive Performance in Former Smokers With and Without Chronic Obstructive Pulmonary Disease

Background Heavy smokers perform worse on neuropsychological assessment than age-matched peers. However, traditional pulmonary measures of airflow limitation and hypoxemia explain only a modest amount of variance in cognition. The current objective was to determine whether carotid artery stiffness is associated with cognition in former smokers beyond the effects of amount of smoking and pulmonary function. Methods and Results Eighty-four former smokers including individuals across a spectrum of airflow limitation severity were included: 30 without chronic obstructive pulmonary disease (Global Initiative for Chronic Obstructive Lung Disease [GOLD] 0 with normal spirometry and lung computed tomography), 31 with mild-moderate chronic obstructive pulmonary disease (GOLD 1-2), and 23 with severe-very severe chronic obstructive pulmonary disease (GOLD 3-4). Participants completed questionnaires, spirometry, carotid ultrasonography, and neuropsychological testing. Multiple linear regression was used to determine whether carotid artery stiffness is associated with neuropsychological performance in 4 cognitive domains after adjusting for age, sex, pack-years of smoking, estimated premorbid intellectual functioning, and airflow limitation. Higher carotid artery β-stiffness index was associated with reduced executive functioning-processing speed in the fully adjusted model (β=-0.49, SE=0.14; P=0.001). Lower premorbid intellectual function, male sex, and presence of airflow limitation (GOLD 1 or 2 and GOLD 3 or 4) were also associated with worse executive functioning-processing speed. β-Stiffness index was not significantly associated with performance in other cognitive domains. Conclusions Carotid artery stiffness is associated with worse performance on executive functioning-processing speed in former smokers beyond the effects of aging, amount of past smoking, severity of airflow limitation, and hypoxemia. Future research should examine whether carotid stiffness can be used to identify former smokers at risk for subsequent cognitive impairment.

Influencing Factors and Exercise Intervention of Cognitive Impairment in Elderly Patients with Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is a common respiratory condition characterized by airflow limitation in the elderly. Airflow limitation is partially reversible and progressive. COPD not only causes a gradual decline in lung function but also affects the function of other systems throughout the body; it also has adverse effects on the central nervous system that can lead to cognitive impairment, especially in elderly patients. Therefore, understanding the influencing factors of cognitive impairment in elderly patients with COPD and applying early intervention are crucial in improving the quality of life of patients and reducing the burden on their families and society. This article mainly discusses the related factors of cognitive impairment in elderly patients with COPD and expands the possible mechanism of exercise in improving cognitive impairment in patients with COPD to provide a reference for the clinical prevention and treatment of cognitive impairment in elderly patients with COPD.

Association between Chronic Obstructive Pulmonary Disease and Dementia: Systematic Review and Meta-Analysis of Cohort Studies

Background

Chronic obstructive pulmonary disease (COPD) is a common disease among the elderly, which has been linked to cognitive decline. However, the relationship between COPD and dementia remains unclear.

Summary

We conducted a systematic literature review by searching databases such as Pubmed, Embase, EBSCO, and Cochrane Library (from inception to April 18, 2018) for studies on COPD that also investigated the prevalence of dementia. We found 3 cohort studies including a total of 39,392 COPD patients. Then we applied the Newcastle-Ottawa Scale to evaluate the risk of bias.

Key Messages

COPD patients faced a higher risk of dementia (HR 1.46; 95% CI 1.22–1.75; p < 0.001). Subgroup analysis on gender determined that the association between COPD and dementia was stronger in male patients (HR 1.49, 95% CI 1.20–1.86, p < 0.001) than in female patients (HR 1.41, 95% CI 1.27–1.57, p < 0.001). A subset study of patients aged >65 years revealed that the HR was greater for patients aged ≥75 years (HR 1.46, 95% CI 1.07–2.00, p = 0.02) than for those aged 65–74 years (HR 1.40, 95% CI 1.28–1.53, p < 0.001). The cohort studies included were from similar population-based databases, suggesting possible regional limitations and publication bias.

Psychological co-morbidities in COPD: Targeting systemic inflammation, a benefit for both?

COPD is a chronic lung disease characterized by persistent respiratory symptoms and airflow limitation due to airway and/or alveolar abnormalities. Furthermore, COPD is often characterized by extrapulmonary manifestations and comorbidities worsening COPD progression and quality of life. A neglected comorbidity in COPD management is mental health impairment defined by anxiety, depression and cognitive problems. This paper summarizes the evidence for impaired mental health in COPD and focuses on current pharmacological intervention strategies. In addition, possible mechanisms in impaired mental health in COPD are discussed with a central role for inflammation. Many comorbidities are associated with multi-organ-associated systemic inflammation in COPD. Considering the accumulative evidence for a major role of systemic inflammation in the development of neurological disorders, it can be hypothesized that COPD-associated systemic inflammation also affects the function of the brain and is an interesting therapeutic target for nutra- and pharmaceuticals.