Cognitive impairment in COPD: should cognitive evaluation be part of respiratory assessment?

The effect of rosemary hydroalcoholic extract on cognitive function and activities of daily living of patients with chronic obstructive pulmonary disease (COPD): A clinical trial

BACKGROUND

In patients living with chronic obstructive pulmonary disease (COPD), cognitive impairment and reduced activities of daily living (ADLs) are associated with poor clinical outcomes.

AIM

The aim of the present study was to determine the effect of rosemary hydroalcoholic extract on cognitive function and ADLs in patients with COPD.

METHODS

A total of 77 COPD patients aged 40-80 years were assigned to two intervention and control groups by random stratified block method in the current tripleblind clinical trial. The intervention group received 500 mg rosemary capsules and the control group received oral capsules containing corn powder twice a day, one to two hours before breakfast and dinner, for two months. The Montreal Cognitive Assessment-Basic (MoCA-B), London Chest Activity of Daily Living scale (LCADL) and Lawton Instrumental Activities of Daily Living (IADL) were used to measure cognitive function and the measure of basic and instrumental daily life activities, before and after the intervention, respectively.

RESULTS

The mean total score of cognitive function (P = 0.022) and the two subscales of abstraction (P = 0.003) and naming (P = 0.034) significantly increased after the intervention in the intervention group. There was no significant difference between the intervention and control groups in terms of changes in the mean scores of IADL and LCADL (P < 0.05). The final statistical model showed that the changes in the total mean score of cognitive function (P = 0.014) and IADL (P = 0.047) in intervention group patients are significantly higher than in the control group after adjusting the effect of obstructive sleep apnea (OSA).

CONCLUSION

The rosemary hydroalcoholic extract can be effective in improving cognitive function and IADL in patients with COPD, but not LCADL.

CLINICAL TRIALS REGISTRATION NUMBER

IRCT20150919024080N16.

Associations of Upper-Extremity Exercise Capacity and Grip Strength With Cognitive Domains in Patients With COPD

BACKGROUND

Cognitive impairment (CI), which has been reported in COPD, has been related to physical performance. However, the association between CI and upper-extremity functions is unknown. We aimed to compare upper-extremity exercise capacity and grip strength between subjects with COPD with and without CI and to determine the relationship of upper-extremity functions with specific cognitive domains.

METHODS

In this cross-sectional study, 76 subjects with COPD (mean age 66.8 ± 7.5 y, FEV1% 47.12 ± 14.10) were classified as with and without CI according to the Montreal Cognitive Assessment. Clinical characteristics, upper-extremity exercise capacity (6-min pegboard ring test [6PBRT]), grip strength (hand dynamometer), dyspnea severity (modified Medical Research Council dyspnea scale), disease-specific health status (COPD Assessment Test), and disease-specific quality of life (St George Respiratory Questionnaire) were compared between groups, and the relationship of upper-extremity functions with cognitive subdomains was analyzed by multivariate regression analysis.

RESULTS

The number of 6PBRT rings (P = .01) and the grip strength (P = .033) were lower in subjects with CI. Subjects with CI had lower FEV1% (P = .038), arterial oxygenation (P = .002), exercise habits (P = .033), health status (P = .01), quality of life (P = .042); and higher dyspnea (P < .001), smoking consumption (P = .032), emergency admission (P = .02), and hospitalization (P = .042). The adjusted model showed that executive functions and attention were related to upper-extremity capacity (β = 14.4 and β = 10.2, respectively) and hand-grip strength (β = 1.85 and β = 1.49, respectively).

CONCLUSIONS

These findings suggest that upper-extremity functions might be decreased especially concerning executive functions and attention in subjects with COPD with CI.

Social Capital Associates With Better Cognitive Health, Oral Health and Epigenetic Age Deceleration: Findings From the Canadian Longitudinal Study on Aging

Background: Social exposures are linked to an array of health outcomes, especially around aging. In this study, we examined the association of social capital, defined as social relationships and networks, with clinical and biological outcomes including cognitive health, oral inflammation, and epigenetic aging. Methods: We used data from the Canadian Longitudinal Study on Aging (CLSA) (n = 1,479; aged 45-85 years), categorizing social capital as structural and cognitive capital. Oral inflammation was determined as the presence of gum bleeding. Epigenetic aging was computed as the difference between chronological age and DNA methylation age. We constructed multivariable regression models adjusted for covariates to assess the relationships of interest. Results: Higher structural social capital was associated with decelerated epigenetic aging and better cognitive health outcomes, while higher cognitive social capital was associated with better cognitive outcomes and less oral inflammation. Conclusion: Enhanced social capital may contribute to better clinical and biological outcomes around aging.

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.

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.

Feasibility of a Home-Based Cognitive-Physical Exercise Program in Patients With Chronic Obstructive Pulmonary Disease: Protocol for a Feasibility and Pilot Randomized Controlled Trial

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a progressive condition associated with physical and cognitive impairments contributing to difficulty in performing activities of daily living (ADLs) that require dual tasking (eg, walking and talking). Despite evidence showing that cognitive decline occurs among patients with COPD and may contribute to functional limitations and decreased health-related quality of life (HRQL), pulmonary rehabilitation continues to focus mainly on physical training (ie, aerobic and strength exercises). An integrated cognitive and physical training program compared to physical training alone may be more effective in increasing dual-tasking ability among people living with COPD, leading to greater improvements in performance of ADLs and HRQL.

OBJECTIVE

The aims of this study are to evaluate the feasibility of an 8-week randomized controlled trial of home-based, cognitive-physical training versus physical training for patients with moderate to severe COPD and derive preliminary estimates of cognitive-physical training intervention efficacy on measures of physical and cognitive function, dual task performance, ADLs, and HRQL.

METHODS

A total of 24 participants with moderate to severe COPD will be recruited and randomized into cognitive-physical training or physical training. All participants will be prescribed an individualized home physical exercise program comprising 5 days of moderate-intensity aerobic exercise (30-50 minutes/session) and 2 days of whole-body strength training per week. The cognitive-physical training group will also perform cognitive training for approximately 60 minutes, 5 days per week via the BrainHQ platform (Posit Science Corporation). Participants will meet once weekly with an exercise professional (via videoconference) who will provide support by reviewing the progression of their training and addressing any queries. Feasibility will be assessed through the recruitment rate, program adherence, satisfaction, attrition, and safety. The intervention efficacy regarding dual task performance, physical function, ADLs, and HRQL will be evaluated at baseline and at 4 and 8 weeks. Descriptive statistics will be used to summarize intervention feasibility. Paired 2-tailed t tests and 2-tailed t tests will be used to compare the changes in the outcome measures over the 8-week study period within and between the 2 randomized groups, respectively.

RESULTS

Enrollment started in January 2022. It is estimated that the enrollment period will be 24 months long, with data collection to be completed by December 2023.

CONCLUSIONS

A supervised home-based cognitive-physical training program may be an accessible intervention to improve dual-tasking ability in people living with COPD. Evaluating the feasibility and effect estimates is a critical first step to inform future clinical trials evaluating this approach and its effects on physical and cognitive function, ADL performance, and HRQL.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05140226; https://clinicaltrials.gov/ct2/show/NCT05140226.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/48666.

Effect of individualized PEEP titration by ultrasonography on perioperative pulmonary protection and postoperative cognitive function in patients with chronic obstructive pulmonary disease

OBJECTIVE

To evaluate the effect of the individualized positive end-expiratory pressure (PEEP) lung protection ventilation strategy by combining driving pressure (ΔP) and pulmonary ultrasound (LUS)-based titration on lung function and postoperative cognitive function in patients with chronic obstructive pulmonary disease (COPD) during laparoscopic surgery.

METHODS

A total of 108 patients with COPD undergoing laparoscopic gastrointestinal surgery under general anesthesia were included in this study. They were randomly divided into three groups (n = 36): traditional volume ventilation group (Group C), fixed PEEP 5 cmH₂O group (Group P), and ΔP combined with LUS-based PEEP titration in the resuscitation room group (Group T). All three groups were given volume ventilation mode, I:E = 1:2; In group C, VT was 10 mL/kg and PEEP was 0 cmH₂O; In groups P and T, VT was 6 mL/kg and PEEP was 5 cmH₂O; After mechanical ventilation for 15 min in Group T, ΔP in combination with LUS was used to titrate PEEP. The oxygenation index (PaO2/FiO2), airway platform pressure (Pplat), dynamic lung compliance (Cdyn), Montreal Cognitive Assessment (MoCA), and venous interleukin-6(IL-6) were recorded at the corresponding time points, and the final PEEP value in Group T was recorded.

RESULTS

The final PEEP value of Group T was (6.4 ± 1.2) cmH₂O; Compared with groups C and P: PaO₂/FiO₂ and Cdyn in Group T were significantly increased (P < 0.05) and value of IL-6 was significantly decreased (P < 0.05) at the corresponding time points. Compared with group C, the MoCA score on day 7 after surgery in Group T was significantly higher (P < 0.05).

CONCLUSION

Compared with the traditional ventilation strategy, the individualized ΔP combined with LUS-based PEEP titration in patients with COPD during the perioperative period of laparoscopic surgery can play a better role in lung protection and can improve postoperative cognitive function.

Cognitive decline and risk of dementia in older adults after diagnosis of chronic obstructive pulmonary disease

Cognitive screening has been proposed for older adults diagnosed with chronic obstructive pulmonary disease (COPD). Therefore, we examined the change over time in cognitive function and the risk of incident dementia in older adults after COPD diagnosis. A sample of 3,982 participants from the population-based cohort study Good Aging in Skåne was followed for 19 years, and 317 incident COPD cases were identified. The cognitive domains of episodic memory, executive function, and language were assessed using neuropsychological tests. Mixed models for repeated measures and a Cox model were implemented. Participants performed, on average, worse over time on all neuropsychological tests after COPD diagnosis in comparison to those without COPD, although statistical significance differences were only observed for episodic memory and language. The groups had a comparable risk of developing dementia. In conclusion, our results indicate that cognitive screening in the early stages of COPD may be of limited clinical relevance.

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.

Preliminary study of assessing cognitive impairment in older patients with chronic obstructive pulmonary disease by using a cognitive functional assessment tool via a touchscreen personal computer

Background

Unique cognitive impairments related to chronic obstructive pulmonary diseases (COPD) have been increasingly reported. Considering the dementia risk and medication management, older patients with COPD should be evaluated for cognitive impairment. This study aimed to examine whether specific cognitive impairments related to COPD could be detected by an assessment tool using a touchscreen personal computer (PC) in older patients with COPD.

Methods

This study included 28 older male patients with COPD and 30 healthy older male individuals. A touchscreen PC-based cognitive assessment application called CogEvo was used to assess and compare the cognitive function according to five domains: spatial cognition, orientation, working memory, executive function, and attention.

Results

Analysis of variance showed an interaction effect on the indices of cognitive function based on five domains between the two groups, indicating differences in the characteristics of cognitive function in such groups. Betweengroup comparisons as a subtest showed that attention, executive function, and working memory were significantly lower in the COPD group than in the healthy group.

Conclusions

CogEvo can detect specific cognitive impairments associated with COPD, suggesting that it can be potentially used as a screening tool for cognitive impairment in older patients with COPD.

Impact of cognitive capacity on physical performance in chronic obstructive pulmonary disease patients: A scoping review

Background: Chronic obstructive pulmonary disease (COPD) is often accompanied by impaired cognitive and physical function. However, the role of cognitive function on motor control and purposeful movement is not well studied. The aim of the review was to determine the impact of cognition on physical performance in COPD. Methods: Scoping review methods were performed including searches of the databases: MEDLINE, EMBASE, Cochrane Systematic Reviews, Cochrane (CENTRAL), APA PsycINFO, and CINAHL. Two reviewers independently assessed articles for inclusion, data abstraction, and quality assessment. Results: Of 11,252 identified articles, 44 met the inclusion criteria. The review included 5743 individuals with COPD (68% male) with the forced expiratory volume in one second range of 24-69% predicted. Cognitive scores correlated with strength, balance, and hand dexterity, while 6-min walk distance (n = 9) was usually similar among COPD patients with and without cognitive impairment. In 2 reports, regression analyses showed that delayed recall and the trail making test were associated with balance and handgrip strength, respectively. Dual task studies (n = 5) reported impaired balance or gait in COPD patients compared to healthy adults. Cognitive or physical Interventions (n = 20) showed variable improvements in cognition and exercise capacity. Conclusions: Cognition in COPD appears to be more related to balance, hand, and dual task function, than exercise capacity.

The role of structured exercise interventions on cognitive function in older individuals with stable Chronic Obstructive Pulmonary Disease: A scoping review

A decline in cognitive performance has been associated with disease severity, exacerbations rate, presence of comorbidities, and low activity level in people with chronic obstructive pulmonary disease (COPD). Participation in exercise programs appears to have neuroprotective effects and to improve cognitive performance in older people. The present work undertook a scoping review of the effects of exercise-based interventions on cognitive function in older individuals with stable COPD.

METHODS

The methodological framework for scoping review was used and electronic searches of five databases performed. Original research and observational studies published between January 2010 and December 2021, administering exercise-based interventions and cognitive function evaluation, were included.

RESULTS

Of 13 full-text manuscripts assessed for eligibility, five were allocated to analysis. Three studies administered exercise training within pulmonary outpatient rehabilitation program (PR), and one inpatient PR. The fifth study conducted a structured training intervention in which either aerobic or a combination with resistance exercises were included. Twelve cognitive function screening tools were used in the five studies included in the analysis. Results extracted were based on 245 COPD (33% female) with moderate to very-severe airflow limitation. Interventions ranged from 12 to 36 sessions. Studies reported statistically significant improvements after intervention in different cognitive function domains, such as global cognition, immediate and delayed recall ability, cognitive flexibility, verbal fluency, attention, abstract reasoning, praxis ability.

CONCLUSIONS

Exercise-based interventions improve several areas of cognitive function in patients with stable COPD. However, the magnitude of gain varies among studies, and this is possibly due to the heterogeneity of tests used. Future research is needed to validate the optimal battery of screening tests, and to support the definition of guidelines for cognitive function evaluation in COPD.

Impact of Coexisting Dementia on Inpatient Outcomes for Patients Admitted with a COPD Exacerbation

Purpose

People with COPD are at a higher risk of cognitive dysfunction than the general population. However, the additional impact of dementia amongst such patients is not well understood, particularly in those admitted with a COPD exacerbation. We assessed the impact of coexisting dementia on inpatient mortality and length of stay (LOS) in patients admitted to hospital with a COPD exacerbation, using the United States based National Inpatient Sample database.

Patients and Methods

Patients aged over 40 years and hospitalised with a primary diagnosis of COPD exacerbation from 2011 to 2015 were included. Cases were grouped into patients with and without dementia. Multivariable logistic regression analysis, stratified by age, was used to assess risk of inpatient deaths. Cox regression was carried out to compare death rates and competing risk analysis gave estimates of discharge rates with time to death a competing variable.

Results

A total of 576,381 patients were included into the analysis, of which 35,372 (6.1%) had co-existent dementia. There were 6413 (1.1%) deaths recorded. The odds of inpatient death were significantly greater in younger patients with dementia (41–64 years) [OR (95% CI) dementia vs without: 1.75 (1.04–2.92), p=0.03]. Cases with dementia also had a higher inpatient mortality rate in the first 4 days [HR (95% CI) dementia vs without: 1.23 (1.08–1.41), p=0.002] and a longer LOS [sub-hazard ratio (95% CI) dementia vs without: 0.93 (0.92–0.94), p<0.001].

Conclusion

Dementia as a comorbidity is associated with worse outcomes based on inpatient deaths and LOS in patients admitted with COPD exacerbations.

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.

A Home-Based Multimedia Pulmonary Rehabilitation Program Improves Clinical Symptoms and Physical Performance of Patients with Chronic Obstructive Pulmonary Disease

Home-based pulmonary rehabilitation can decrease symptoms in chronic obstructive pulmonary disease (COPD) patients. The purpose of this study was to compare the effects of a home-based pulmonary rehabilitation by instructive multimedia in the form of videos and flip charts on clinical symptoms and exercise performance in COPD patients. An eight-week home-based pulmonary rehabilitation program was performed with twenty COPD patients older than 60 years of age with moderate to severe stages. They were separated into two groups: a multimedia group (n = 10) and a control group, which was only provided with telephone monitoring (n = 10). Clinical symptoms were measured by using the clinical COPD questionnaire (CCQ), and exercise performance was measured using a six-minute walk test (6MWT) and an upper-lower limb muscle strengthening test. After 8 weeks, the results showed that both groups showed a statistically significant decrease in the CCQ (p < 0.05). The multimedia group showed a statistically significant increase in the lower-limb muscle strengthening (p < 0.05), while the control group was not found to show a statistically significant increase in the lower-limb muscle strengthening. Therefore, a pulmonary rehabilitation program using multimedia at home can lessen symptoms and improve exercise performance in COPD patients.

Working memory training efficacy in COPD: the randomised, double-blind, placebo-controlled Cogtrain trial

BACKGROUND

Cognitive impairment is highly prevalent in COPD and is associated with a sedentary lifestyle, unhealthy diet and increased cognitive stress susceptibility. Enhancement of cognitive performance by working memory training (WMT) may reverse these effects. Therefore, this study aimed to investigate the efficacy of WMT in COPD on cognitive performance, healthy lifestyle behaviours and cognitive stress susceptibility.

METHODS

The double-blind randomised, placebo-controlled Cogtrain trial consisted of a 12-week training phase comprising 30 active or sham WMT sessions, followed by a second 12-week maintenance phase with 12 sessions. Measurements took place at baseline and after the first and second phases. The primary outcome was cognitive performance. Secondary outcomes were the recall of prespecified healthy lifestyle goals, physical capacity and activity, dietary quality and cognitive stress susceptibility. Motivation towards exercising and healthy eating and psychological wellbeing were exploratory outcomes.

RESULTS

Sixty-four patients with moderate COPD (45% male, aged 66.2±7.2 years, median forced expiratory volume in 1 s 60.6% predicted) were randomised. WMT significantly increased patients' performance on the trained tasks in the first phase, which remained stable in the second phase. Of the 17 cognitive outcome measures, only one measure of memory improved after the first phase and one measure of reaction time after the second phase. This intervention did not influence physical capacity and activity, recall of prespecified healthy lifestyle goals, psychological wellbeing or cognitive stress susceptibility.

CONCLUSION

WMT improved performance on the trained tasks but not overall cognitive performance, healthy lifestyle behaviours or cognitive stress susceptibility in patients with COPD.

Neurovascular Alterations in Vascular Dementia: Emphasis on Risk Factors

Vascular dementia (VaD) constitutes the second most prevalent cause of dementia in the world after Alzheimer’s disease (AD). VaD regroups heterogeneous neurological conditions in which the decline of cognitive functions, including executive functions, is associated with structural and functional alterations in the cerebral vasculature. Among these cerebrovascular disorders, major stroke, and cerebral small vessel disease (cSVD) constitute the major risk factors for VaD. These conditions alter neurovascular functions leading to blood-brain barrier (BBB) deregulation, neurovascular coupling dysfunction, and inflammation. Accumulation of neurovascular impairments over time underlies the cognitive function decline associated with VaD. Furthermore, several vascular risk factors, such as hypertension, obesity, and diabetes have been shown to exacerbate neurovascular impairments and thus increase VaD prevalence. Importantly, air pollution constitutes an underestimated risk factor that triggers vascular dysfunction via inflammation and oxidative stress. The review summarizes the current knowledge related to the pathological mechanisms linking neurovascular impairments associated with stroke, cSVD, and vascular risk factors with a particular emphasis on air pollution, to VaD etiology and progression. Furthermore, the review discusses the major challenges to fully elucidate the pathobiology of VaD, as well as research directions to outline new therapeutic interventions.

APTA Cross Sections and Academies Recommendations for COVID-19 Core Outcome Measures

The novel coronavirus (COVID-19) emerged as a major health concern within the United States in early 2020. Because this is a novel virus, little guidance exists for best practice to evaluate this population within the field of physical therapy.

Telehealth interventions: remote monitoring and consultations for people with chronic obstructive pulmonary disease (COPD)

BACKGROUND

Chronic obstructive pulmonary disease (COPD, including bronchitis and emphysema) is a chronic condition causing shortness of breath, cough, and exacerbations leading to poor health outcomes. Face-to-face visits with health professionals can be hindered by severity of COPD or frailty, and by people living at a distance from their healthcare provider and having limited access to services. Telehealth technologies aimed at providing health care remotely through monitoring and consultations could help to improve health outcomes of people with COPD.

OBJECTIVES

To assess the effectiveness of telehealth interventions that allow remote monitoring and consultation and multi-component interventions for reducing exacerbations and improving quality of life, while reducing dyspnoea symptoms, hospital service utilisation, and death among people with COPD.

SEARCH METHODS

We identified studies from the Cochrane Airways Trials Register. Additional sources searched included the US National Institutes of Health Ongoing Trials Register, the World Health Organization International Clinical Trials Registry Platform, and the IEEEX Xplore Digital Library. The latest search was conducted in April 2020. We used the GRADE approach to judge the certainty of evidence for outcomes.

SELECTION CRITERIA

Eligible randomised controlled trials (RCTs) included adults with diagnosed COPD. Asthma, cystic fibrosis, bronchiectasis, and other respiratory conditions were excluded. Interventions included remote monitoring or consultation plus usual care, remote monitoring or consultation alone, and mult-component interventions from all care settings. Quality of life scales included St George's Respiratory Questionnaire (SGRQ) and the COPD Assessment Test (CAT). The dyspnoea symptom scale used was the Chronic Respiratory Disease Questionnaire Self-Administered Standardized Scale (CRQ-SAS).

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodological procedures. We assessed confidence in the evidence for each primary outcome using the GRADE method. Primary outcomes were exacerbations, quality of life, dyspnoea symptoms, hospital service utilisation, and mortality; a secondary outcome consisted of adverse events.

MAIN RESULTS

We included 29 studies in the review (5654 participants; male proportion 36% to 96%; female proportion 4% to 61%). Most remote monitoring interventions required participants to transfer measurements using a remote device and later health professional review (asynchronous). Only five interventions transferred data and allowed review by health professionals in real time (synchronous). Studies were at high risk of bias due to lack of blinding, and certainty of evidence ranged from moderate to very low. We found no evidence on comparison of remote consultations with or without usual care. Remote monitoring plus usual care (8 studies, 1033 participants) Very uncertain evidence suggests that remote monitoring plus usual care may have little to no effect on the number of people experiencing exacerbations at 26 weeks or 52 weeks. There may be little to no difference in effect on quality of life (SGRQ) at 26 weeks (very low to low certainty) or on hospitalisation (all-cause or COPD-related; very low certainty). COPD-related hospital re-admissions are probably reduced at 26 weeks (hazard ratio 0.42, 95% confidence interval (CI) 0.19 to 0.93; 106 participants; moderate certainty). There may be little to no difference in deaths between intervention and usual care (very low certainty). We found no evidence for dyspnoea symptoms or adverse events. Remote monitoring alone (10 studies, 2456 participants) Very uncertain evidence suggests that remote monitoring may result in little to no effect on the number of people experiencing exacerbations at 41 weeks (odds ratio 1.02, 95% CI 0.67 to 1.55). There may be little to no effect on quality of life (SGRQ total at 17 weeks, or CAT at 38 and 52 weeks; very low certainty). There may be little to no effect on dyspnoea symptoms on the CRQ-SAS at 26 weeks (low certainty). There may be no difference in effects on the number of people admitted to hospital (very low certainty) or on deaths (very low certainty). We found no evidence for adverse events. Multi-component interventions with remote monitoring or consultation component (11 studies, 2165 participants) Very uncertain evidence suggests that multi-component interventions may have little to no effect on the number of people experiencing exacerbations at 52 weeks. Quality of life at 13 weeks may improve as seen in SGRQ total score (mean difference -9.70, 95% CI -18.32 to -1.08; 38 participants; low certainty) but not at 26 or 52 weeks (very low certainty). COPD assessment test (CAT) scores may improve at a mean of 38 weeks, but evidence is very uncertain and interventions are varied. There may be little to no effect on the number of people admitted to hospital at 33 weeks (low certainty). Multi-component interventions are likely to result in fewer people re-admitted to hospital at a mean of 39 weeks (OR 0.50, 95% CI 0.31 to 0.81; 344 participants, 3 studies; moderate certainty). There may be little to no difference in death at a mean of 40 weeks (very low certainty). There may be little to no effect on people experiencing adverse events (very low certainty). We found no evidence for dyspnoea symptoms.

AUTHORS' CONCLUSIONS

Remote monitoring plus usual care provided asynchronously may not be beneficial overall compared to usual care alone. Some benefit is seen in reduction of COPD-related hospital re-admissions, but moderate-certainty evidence is based on one study. We have not found any evidence for dyspnoea symptoms nor harms, and there is no difference in fatalities when remote monitoring is provided in addition to usual care. Remote monitoring interventions alone are no better than usual care overall for health outcomes. Multi-component interventions with asynchronous remote monitoring are no better than usual care but may provide short-term benefit for quality of life and may result in fewer re-admissions to hospital for any cause. We are uncertain whether remote monitoring is responsible for the positive impact on re-admissions, and we are unable to discern the long-term benefits of receiving remote monitoring as part of patient care. Owing to paucity of evidence, it is unclear which COPD severity subgroups would benefit from telehealth interventions. Given there is no evidence of harm, telehealth interventions may be beneficial as an additional health resource depending on individual needs based on professional assessment. Larger studies can determine long-term effects of these interventions.

Benefits of pulmonary rehabilitation in COPD patients with mild cognitive impairment - A pilot study

BACKGROUND

Cognitive impairment might interfere with the efficacy of Pulmonary Rehabilitation (PR) in Chronic Obstructive Pulmonary Disease (COPD). We aimed to identify differential responses to PR between cognitively impaired (CI) and cognitively normal (CN) COPD patients by assessing health status and exercise capacity.

METHODS

Sixty patients (FEV₁: 47 ± 15%) were classified as CI or CN according to the Montreal Cognitive Assessment (MoCA ≤25points) and completed a 3-week inpatient PR program. Cognitive function (neuropsychological battery), health-status (36-Item Short Form Survey [SF-36]), and exercise capacity (6-min walk test [6MWT], cycle-endurance test [CET]) were assessed before and after PR. Responsiveness to PR was estimated by mean change (delta-value [Δ]) and the d-Effect Size (ES).

RESULTS

Twenty-five COPD patients (42%) presented evidence of mild CI prior to PR. Both, CI and CN patients significantly improved global cognitive function, health status (the majority of SF-36 components), and exercise capacity (6MWT and cycle endurance) in response to PR. Compared to CN, CI patients did not improve SF-36 subdomains of "role emotional" and "bodily pain", and demonstrated a lower magnitude of improvement in 6MWT ([Δ]: 25 m; ES: 0.21) compared to CN ([Δ]: 46 m; ES: 0.54).

CONCLUSIONS

PR has favorable effects on global cognitive function, health status, and exercise capacity in both CI and CN COPD patients. There was no concrete evidence to indicate interference of cognitive impairment to PR effectiveness.

Effects of a cognitive rehabilitation programme on cognitive function, self-management and quality of life in patients with chronic obstructive pulmonary disease

AIM

The study purpose was to investigate effects of a cognitive rehabilitation programme on cognitive function, self-management and quality of life in patients with chronic obstructive pulmonary disease.

BACKGROUND

Cognitive impairment is frequently observed in chronic obstructive pulmonary disease patients, and it interferes with many aspects of self-management, which is fundamental to disease management and quality of life.

DESIGN

The design is quasi-experimental.

METHODS

Data collection was performed between June 2018 and March 2019. Study participants were 60 in- or out-patients with chronic obstructive pulmonary disease. The cognitive rehabilitation programme involved six 30-min sessions administered over a period of 2 weeks and consisted of six areas: attention, memory, language, visuospatial perception, executive function and problem solving. Cognitive function, self-management and quality of life were measured at three times (preintervention and immediately and 4 weeks after intervention).

RESULTS

Cognitive function, self-management and quality of life were found to be significantly improved over time after administration of the cognitive rehabilitation programme. However, no significant improvement was observed in the control group.

CONCLUSIONS

Our findings support the potential usefulness of cognitive intervention to promote cognitive function, self-management ability and quality of life in patients with chronic obstructive pulmonary disease.

The emerging role of nebulization for maintenance treatment of chronic obstructive pulmonary disease at home

Inhalation therapy is the cornerstone of chronic obstructive pulmonary disease (COPD) management. However, for many COPD patients who are managed at home, nebulization therapy offers an effective alternative treatment and fulfills the gap of catering to the specific population of patients who are unable to use handheld inhaler devices appropriately. The present review highlights key aspects, namely selection of the right beneficiaries for home nebulization, available drugs in nebulized formulations for the treatment of COPD, and the importance of care, cleaning, and maintenance, which are prerequisites for ensuring successful nebulization therapy.

Extra-pulmonary manifestations of COPD and the role of pulmonary rehabilitation: a symptom-centered approach

Introduction: Chronic obstructive pulmonary disease (COPD) is a complex and heterogenous disease that is associated with a range of respiratory and non-respiratory symptoms, which highly contribute to the daily burden of the disease. Symptoms burden remains high despite optimal bronchodilator therapy, but pulmonary rehabilitation (PR) is an effective intervention to improve patients' symptoms. A comprehensive interdisciplinary approach within the framework of a PR program is warranted to tackle these complex symptoms and their consequences. Areas covered: This narrative review describes how symptoms of dyspnea, fatigue, cough, sputum, anxiety, depression, pain, sleep disturbances, and cognitive decline arise in COPD and can contribute to several non-pulmonary manifestations of the disease. It also describes evidence of the effectiveness of interdisciplinary PR programs to counteract these symptoms. A literature search was performed on PubMed and Scopus between June and July 2020. Expert opinion: Respiratory and non-respiratory symptoms are highly prevalent, often not comprehensively assessed, and result in several extra-pulmonary manifestations of the disease (physical, emotional and social). Interdisciplinary PR programs can improve these negative manifestations through different pathways, contributing for an effective symptoms' management. A thorough assessment of symptoms (beyond dyspnea) should be routinely performed and may support the identification of treatable traits, allowing the tailoring of PR interventions and assessment of their real-life impact.

Socioeconomic Disparities and Gender Inequalities in Dementia: a Community-Dwelling Population Study from a Middle-Income Country

The proportion of the world's older adults and of its dementia cases is increasing in low and middle-income countries. This is particularly true in Colombia. There, the number of individuals with dementia may increase five-fold by 2050. Yet research is lacking on dementia in such settings. This work estimates the prevalence of dementia in a community-dwelling population in Colombia. It also assesses how gender-based differences in cardiovascular conditions and socioeconomic disparities affect dementia. This work analyzes data on 2000 respondents at least 60 years of age in the Health, Well-Being, And Aging (SABE) study in Bogota. Respondents with dementia are those who have cognitive impairment and at least two limitations in instrumental activities of daily living. The SABE study finds 8.4% of respondents have dementia. Age, cardiovascular risks, and socioeconomic disparities contributed to higher odds of dementia. The contributors to dementia can differ for men and women. For example, socioeconomic disparities were a larger contributor to dementia for women than men. The findings support the cognitive reserve hypothesis on dementia. This holds that pre-existing cognitive processes and compensatory mechanisms influence dementia. Women in Latin America are more likely to suffer from socioeconomic disparities that limit their cognitive reserve. This research points to several policy implications that can help offset these disparities and reduce the prevalence of dementia.

Experimental dyspnoea interferes with locomotion and cognition: a randomised trial

BACKGROUND

Chronic respiratory diseases are associated with cognitive dysfunction, but whether dyspnoea by itself negatively impacts on cognition has not been demonstrated. Cortical networks engaged in subjects experiencing dyspnoea are also activated during other tasks that require cognitive input and this may provoke a negative impact through interference with each other.

METHODS

This randomised, crossover trial investigated whether experimentally-induced dyspnoea would negatively impact on locomotion and cognitive function among 40 healthy adults. Crossover conditions were unloaded breathing or loaded breathing using an inspiratory threshold load. To evaluate locomotion, participants were assessed by the Timed Up and Go (TUG) test. Cognitive function was assessed by categorical and phonemic verbal fluency tests, the Trail Making Tests (TMTs) A and B (executive function), the CODE test from the Wechsler Adult Intelligence Scale (WAIS)-IV (processing speed) and by direct and indirect digit span (working memory).

RESULTS

The mean time difference to perform the TUG test between unloaded and loaded breathing was -0.752 s (95% CI -1.012 to -0.492 s) (p<0.001). Executive function, processing speed and working memory performed better during unloaded breathing, particularly for subjects starting first with the loaded breathing condition.

CONCLUSION

Our data suggest that respiratory threshold loading to elicit dyspnoea had a major impact on locomotion and cognitive function in healthy adults.

Moderate-to-Severe Obstructive Sleep Apnea and Cognitive Function Impairment in Patients with COPD

Purpose

Prior studies have indicated that patients with chronic obstructive pulmonary disease (COPD) exhibit significant cognitive defects on neuropsychological testing. Obstructive sleep apnea (OSA) is common in patients with COPD and is associated with reduced cognitive function; however, the combined impact of these two conditions on cognitive function is unknown. The aim of the study was to investigate the impact of OSA on cognitive impairment in patients with COPD.

Methods

Sixty-five stable COPD patients aged over 60 years underwent overnight polysomnography (PSG). Global cognitive functions were evaluated using the Mini-Mental State Examination (MMSE).

Results

Compared to patients with COPD alone, patients with both COPD and OSA performed worse on the MMSE (25.5±2.9 vs 23.5±3.2; p=0.01) and were more likely to be at risk for developing dementia based on the MMSE score (MMSE≤24) (31% vs 66%; p<0.01), independent of key demographic, educational and medical variables known to affect cognitive function in COPD. COPD patients with an apnea hypopnea index (AHI) of ≥30 events/h had lower MMSE scores than those with an AHI of <15 events/h. In addition to age and education level, the severity of nocturnal intermittent hypoxia is an independent predictor of the risk of dementia in patients with COPD (OR=1.24, 95% CI 1.04-1.48, p = 0.02).

Conclusion

The current findings indicate that patients with COPD with comorbid OSA may be at greater risk for global cognitive impairment relative to patients with COPD alone. The mechanisms underlying the exaggerated cognitive dysfunction seem to be related to intermittent hypoxia. Further work is needed to understand the impact of OSA on the specific domains of cognitive impairment and the therapeutic implications of OSA in COPD.

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.

Improvements in functional and cognitive status following short-term pulmonary rehabilitation in COPD lung transplant recipients: a pilot study

BACKGROUND

Pulmonary rehabilitation (PR) following lung transplantation (LTx) is considered part of the optimal treatment in chronic obstructive pulmonary disease (COPD) for favourable post-operative outcomes. We investigated the effects of a PR intervention in the post-transplant phase with regard to lung function, exercise responses and cognitive function in COPD LTx recipients.

METHODS

24 COPD LTx recipients (mean±sd forced expiratory volume in 1 s 75±22% predicted) were assigned to a comprehensive 3-week inpatient PR programme. Changes from PR admission to discharge in lung function variables, 6-min walk test-derived outcomes and cognitive function were assessed and examined for several factors. The magnitude of changes was interpreted by effect size (ES).

RESULTS

In response to the PR intervention, LTx recipients had improved lung function with regard to diffusing capacity of the lung for carbon monoxide (+4.3%; p=0.012) and static hyperinflation (residual volume/total lung capacity -2.3%; p=0.017), increased exercise capacity (6-min walk test +86 m; p<0.001), and had small to large improvements (ES range 0.23-1.00; all p≤0.34) in 50% of the administered cognitive tests. Learning skills and memory ability presented the greatest benefits (ES composite scores 0.62 and 0.31, respectively), which remained similar after stratification by single or bilateral LTx and sex.

CONCLUSIONS

PR is an effective treatment for LTx recipients in the post-transplant phase, improving lung function, exercise responses, and domains of cognitive function of learning, memory and psychomotor speed. PR may facilitate the course of post-operative treatment and should be recommended in LTx.

Ventilatory and integrated physiological responses to chronic hypercapnia in goats

KEY POINTS

Chronic hypercapnia per se has distinct effects on the mechanisms regulating steady-state ventilation and the CO₂ /H⁺ chemoreflex. Chronic hypercapnia leads to sustained hyperpnoea that exceeds predicted ventilation based upon the CO₂ /H⁺ chemoreflex. There is an integrative ventilatory, cardiovascular and metabolic physiological response to chronic hypercapnia. Chronic hypercapnia leads to deterioration of cognitive function.

ABSTRACT

Respiratory diseases such as chronic obstructive pulmonary disease (COPD) often lead to chronic hypercapnia which may exacerbate progression of the disease, increase risk of mortality and contribute to comorbidities such as cognitive dysfunction. Determining the contribution of hypercapnia per se to adaptations in ventilation and cognitive dysfunction within this patient population is complicated by the presence of multiple comorbidities. Herein, we sought to determine the role of chronic hypercapnia per se on the temporal pattern of ventilation and the ventilatory CO₂ /H⁺ chemoreflex by exposing healthy goats to either room air or an elevated inspired CO₂ (InCO₂ ) of 6% for 30 days. A second objective was to determine whether chronic hypercapnia per se contributes to cognitive dysfunction. During 30 days of exposure to 6% InCO₂ , steady-state (SS) ventilation ( V ̇ _I ) initially increased to 335% of control, and then within 1-5 days decreased and stabilized at ∼230% of control. There was an initial respiratory acidosis that was partially mitigated over time due to increased arterial [HCO₃ ^- ]. There was a transient decrease in the ventilatory CO₂ /H⁺ chemoreflex, followed by return to pre-exposure levels. The SS V ̇ _I during chronic hypercapnia was greater than predicted from the acute CO₂ /H⁺ chemoreflex, suggesting separate mechanisms regulating SS V ̇ _I and the chemoreflex. Finally, as assessed by a shape discrimination test, we found a sustained decrease in cognitive function during chronic hypercapnia. We conclude that chronic hypercapnia per se results in: (1) a disconnect between SS V ̇ _I and the CO₂ /H⁺ chemoreflex, and (2) deterioration of cognitive function.

Fatigue in Chronic Respiratory Diseases: Theoretical Framework and Implications For Real-Life Performance and Rehabilitation

Fatigue is a primary disabling symptom in chronic respiratory diseases (CRD) with major clinical implications. However, fatigue is not yet sufficiently explored and is still poorly understood in CRD, making this symptom underdiagnosed and undertreated in these populations. Fatigue is a dynamic phenomenon, particularly in such evolving diseases punctuated by acute events which can, alone or in combination, modulate the degree of fatigue experienced by the patients. This review supports a comprehensive inter-disciplinary approach of CRD-related fatigue and emphasizes the need to consider both its performance and perceived components. Most studies in CRD evaluated perceived fatigue as a trait characteristic using multidimensional scales, providing precious information about its prevalence and clinical impact. However, these scales are not adapted to understand the complex dynamics of fatigue in real-life settings and should be augmented with ecological assessment of fatigue. The state level of fatigue must also be considered during physical tasks as severe fatigue can emerge rapidly during exercise. CRD patients exhibit alterations in both peripheral and central nervous systems and these abnormalities can be exacerbated during exercise. Laboratory tests are necessary to provide mechanistic insights into how and why fatigue develops during exercise in CRD. A better knowledge of the neurophysiological mechanisms underlying perceived and performance fatigability and their influence on real-life performance will enable the development of new individualized countermeasures. This review aims first to shed light on the terminology of fatigue and then critically considers the contemporary models of fatigue and their relevance in the particular context of CRD. This article then briefly reports the prevalence and clinical consequences of fatigue in CRD and discusses the strengths and weaknesses of various fatigue scales. This review also provides several arguments to select the ideal test of performance fatigability in CRD and to translate the mechanistic laboratory findings into the clinical practice and real-world performance. Finally, this article discusses the dose-response relationship to training and the feasibility and validity of using the fatigue produced during exercise training sessions in CRD to optimize exercise training efficiency. Methodological concerns, examples of applications in selected diseases and avenues for future research are also provided.

Type A Behavior Pattern, Impulsiveness, Risk Propensity, and Empathy as Predictors of Dyspnea and Number of Infections in Men with Chronic Obstructive Pulmonary Disease: A Cross-Sectional Study

BACKGROUND Stress and psychological factors can induce dyspnea in patients with chronic obstructive pulmonary disease (COPD). The aim of this study was to assess selected elements of the clinical presentation of COPD in the context of the severity of type A pattern of behavior, impulsiveness, and tendency for empathy. MATERIAL AND METHODS This was a cross-sectional study. The study group consisted of 179 men with COPD and the control group consisted of 31 healthy male smokers. In all patients, the number of infectious exacerbations over the past year, the result on the dyspnea scale (MRC), and the FEV1-to- predicted FEV1 ratio was assessed. The A pattern of behavior was measured using the Type A scale. To measure impulsivity, risk propensity, and empathy, the IVE impulsivity questionnaire was used. RESULTS An increase in the number of infectious exacerbations was associated with an increased score on the Type A scale, an increase in risk propensity, and a decrease in impulsivity score. Increased severity of dyspnea was associated with an increase in Type A behavior pattern score and an increase in the risk propensity score. CONCLUSIONS Type A behavior pattern and risk propensity are independent predictors of the number of infections in the last year and of the subjective severity of dyspnea among men with COPD and healthy male smokers.

Cerebral oxygen availability during exercise in COPD patients with cognitive impairment

Insufficient cerebral blood flow regulation to meet increasing metabolic demand during physical exertion could be associated with cognitive impairment. We compared cerebral oxygen availability during exercise in cognitively impaired (CI) to cognitively normal (CN) COPD patients. Fifty-two patients (FEV₁: 51 ± 16%) were classified as CN or CI according to the Montreal Cognitive Assessment. Patients performed cycle-ergometry at 75% peak capacity with continuous measurement of Near-Infrared Spectroscopy frontal-cortex Tissue oxygen Saturation Index (TSI), cerebral haemoglobin indices (oxy/deoxy/total- Hb), transcutaneous carbon-dioxide partial pressure (TcPCO₂), and arterial oxygen saturation (SpO₂). Twenty-one patients (40%) presented evidences of CI. During exercise, CN and CI patients exhibited mild to moderate SpO₂decline (nadir[Δ]≥ -3 ± 2% and -5 ± 3%, respectively) but preserved baseline frontal-cortex TSI levels, whilst presenting small TcPCO₂ perturbations and increased cerebral total-Hb (post [Δ]≥ 2.0 ± 3 μM sec^-1). CI patients preserve the capacity to adequately maintain cerebral oxygen availability during submaximal exercise. Therefore, rehabilitative exercise training in CI patients with COPD exhibiting mild to moderate exercise-induced SpO₂ decline does not appear to lead to reduced cerebral oxygen availability.