Brain Activation during Perception and Anticipation of Dyspnea in Chronic Obstructive Pulmonary Disease

Blunted perception of breathlessness in three cases of low grade insular-glioma

Better understanding of breathlessness perception addresses an unmet clinical need for more effective treatments for intractable dyspnoea, a prevalent symptom of multiple medical conditions. The insular-cortex is predominantly activated in brain-imaging studies of dyspnoea, but its precise role remains unclear. We measured experimentally-induced hypercapnic air-hunger in three insular-glioma patients before and after surgical resection. Tests involved one-minute increments in inspired CO2, raising end-tidal PCO2 to 7.5 mmHg above baseline (38.5 ± 5.7 mmHg), whilst ventilation was constrained (10.7 ± 2.3 L/min). Patients rated air-hunger on a visual analogue scale (VAS). Patients had lower stimulus-response (2.8 ± 2 vs. 11 ± 4 %VAS/mmHg; p = 0.004), but similar threshold (40.5 ± 3.9 vs. 43.2 ± 5.1 mmHg), compared to healthy individuals. Volunteered comments implicated diminished affective valence. After surgical resection; sensitivity increased in one patient, decreased in another, and other was unable to tolerate the ventilatory limit before any increase in inspired CO2.We suggest that functional insular-cortex is essential to register breathlessness unpleasantness and could be targeted with neuromodulation in chronically-breathless patients. Neurological patients with insula involvement should be monitored for blunted breathlessness to inform clinical management.

Dyspnoea in acutely ill mechanically ventilated adult patients: an ERS/ESICM statement

This statement outlines a review of the literature and current practice concerning the prevalence, clinical significance, diagnosis and management of dyspnoea in critically ill, mechanically ventilated adult patients. It covers the definition, pathophysiology, epidemiology, short- and middle-term impact, detection and quantification, and prevention and treatment of dyspnoea. It represents a collaboration of the European Respiratory Society and the European Society of Intensive Care Medicine. Dyspnoea ranks among the most distressing experiences that human beings can endure. Approximately 40% of patients undergoing invasive mechanical ventilation in the intensive care unit (ICU) report dyspnoea, with an average intensity of 45 mm on a visual analogue scale from 0 to 100 mm. Although it shares many similarities with pain, dyspnoea can be far worse than pain in that it summons a primal fear response. As such, it merits universal and specific consideration. Dyspnoea must be identified, prevented and relieved in every patient. In the ICU, mechanically ventilated patients are at high risk of experiencing breathing difficulties because of their physiological status and, in some instances, because of mechanical ventilation itself. At the same time, mechanically ventilated patients have barriers to signalling their distress. Addressing this major clinical challenge mandates teaching and training, and involves ICU caregivers and patients. This is even more important because, as opposed to pain which has become a universal healthcare concern, very little attention has been paid to the identification and management of respiratory suffering in mechanically ventilated ICU patients.

Dyspnoea in acutely ill mechanically ventilated adult patients: an ERS/ESICM statement

This statement outlines a review of the literature and current practice concerning the prevalence, clinical significance, diagnosis and management of dyspnoea in critically ill, mechanically ventilated adult patients. It covers the definition, pathophysiology, epidemiology, short- and middle-term impact, detection and quantification, and prevention and treatment of dyspnoea. It represents a collaboration of the European Respiratory Society (ERS) and the European Society of Intensive Care Medicine (ESICM). Dyspnoea ranks among the most distressing experiences that human beings can endure. Approximately 40% of patients undergoing invasive mechanical ventilation in the intensive care unit (ICU) report dyspnoea, with an average intensity of 45 mm on a visual analogue scale from 0 to 100 mm. Although it shares many similarities with pain, dyspnoea can be far worse than pain in that it summons a primal fear response. As such, it merits universal and specific consideration. Dyspnoea must be identified, prevented and relieved in every patient. In the ICU, mechanically ventilated patients are at high risk of experiencing breathing difficulties because of their physiological status and, in some instances, because of mechanical ventilation itself. At the same time, mechanically ventilated patients have barriers to signalling their distress. Addressing this major clinical challenge mandates teaching and training, and involves ICU caregivers and patients. This is even more important because, as opposed to pain which has become a universal healthcare concern, very little attention has been paid to the identification and management of respiratory suffering in mechanically ventilated ICU patients.

Episodic breathlessness in patients with cancer: definition, terminology, clinical features - integrative systematic review

PURPOSE

Breatlessness flares directly impair quality of life of patients with cancer. The aim of this review was to analyse and synthesise the available information related to its terminology, definition and clinical features in patients with cancer.

METHODS

Integrative systematic review according to Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. Literature search was conducted in MEDLINE PubMed, CINAHLPlus, Web of Science, Cochrane Central Register Controlled Trials CENTRAL, Scopus and OpenAire.

RESULTS

Data from 1065 patients with cancer included in 12 studies were analysed. The preferred term for breathlessness flares was episodic dyspnoea (ED). The reported frequency of ED was 20.4% (70.9% in patients reporting background dyspnoea (BD)). ED intensity was moderate to severe with short duration (<10 min) in >80% of patients. The most common trigger was exertion (>90%) followed by emotional or environmental factors. ED management consisted mainly of pharmacological and non-pharmacological measures.

CONCLUSIONS

This systematic review shows that ED is common in patients with cancer, especially in those with BD. Further studies are urgently needed to better understand this condition and to develop specific therapeutic management.

PROSPERO REGISTRATION NUMBER

CRD42019126708.

Brain activity measured by functional brain imaging predicts breathlessness improvement during pulmonary rehabilitation

BACKGROUND

Chronic breathlessness in chronic obstructive pulmonary disease (COPD) is effectively treated with pulmonary rehabilitation. However, baseline patient characteristics predicting improvements in breathlessness are unknown. This knowledge may provide better understanding of the mechanisms engaged in treating breathlessness and help to individualise therapy. Increasing evidence supports the role of expectation (ie, placebo and nocebo effects) in breathlessness perception. In this study, we tested functional brain imaging markers of breathlessness expectation as predictors of therapeutic response to pulmonary rehabilitation, and asked whether D-cycloserine, a brain-active drug known to influence expectation mechanisms, modulated any predictive model.

METHODS

Data from 71 participants with mild-to-moderate COPD recruited to a randomised double-blind controlled experimental medicine study of D-cycloserine given during pulmonary rehabilitation were analysed (ID: NCT01985750). Baseline variables, including brain-activity, self-report questionnaires responses, clinical measures of respiratory function and drug allocation were used to train machine-learning models to predict the outcome, a minimally clinically relevant change in the Dyspnoea-12 score.

RESULTS

Only models that included brain imaging markers of breathlessness-expectation successfully predicted improvements in Dyspnoea-12 score (sensitivity 0.88, specificity 0.77). D-cycloserine was independently associated with breathlessness improvement. Models that included only questionnaires and clinical measures did not predict outcome (sensitivity 0.68, specificity 0.2).

CONCLUSIONS

Brain activity to breathlessness related cues is a strong predictor of clinical improvement in breathlessness over pulmonary rehabilitation. This implies that expectation is key in breathlessness perception. Manipulation of the brain's expectation pathways (either pharmacological or non-pharmacological) therefore merits further testing in the treatment of chronic breathlessness.

Impact of trigeminal nerve and/or olfactory nerve stimulation on activity of human brain regions involved in the perception of breathlessness

Breathlessness is a centrally processed symptom, as evidenced by activation of distinct brain regions such as the insular cortex and amygdala, during the anticipation and/or perception of breathlessness. Inhaled L-menthol or blowing cool air to the face/nose, both selective trigeminal nerve (TGN) stimulants, relieve breathlessness without concurrent improvements in physiological outcomes (e.g., breathing pattern), suggesting a possible but hitherto unexplored central mechanism of action. Four databases were searched to identify published reports supporting a link between TGN stimulation and activation of brain regions involved in the anticipation and/or perception of breathlessness. The collective results of the 29 studies demonstrated that TGN stimulation activated 12 brain regions widely implicated in the anticipation and/or perception of breathlessness, including the insular cortex and amygdala. Inhaled L-menthol or cool air to the face activated 75% and 33% of these 12 brain regions, respectively. Our findings support the hypothesis that TGN stimulation contributes to breathlessness relief by altering the activity of brain regions involved in its central neural processing.

Nonpharmacological management of psychological distress in people with COPD

Psychological distress is prevalent in people with COPD and relates to a worse course of disease. It often remains unrecognised and untreated, intensifying the burden on patients, carers and healthcare systems. Nonpharmacological management strategies have been suggested as important elements to manage psychological distress in COPD. Therefore, this review presents instruments for detecting psychological distress in COPD and provides an overview of available nonpharmacological management strategies together with available scientific evidence for their presumed benefits in COPD. Several instruments are available for detecting psychological distress in COPD, including simple questions, questionnaires and clinical diagnostic interviews, but their implementation in clinical practice is limited and heterogeneous. Moreover, various nonpharmacological management options are available for COPD, ranging from specific cognitive behavioural therapy (CBT) to multi-component pulmonary rehabilitation (PR) programmes. These interventions vary substantially in their specific content, intensity and duration across studies. Similarly, available evidence regarding their efficacy varies significantly, with the strongest evidence currently for CBT or PR. Further randomised controlled trials are needed with larger, culturally diverse samples and long-term follow-ups. Moreover, effective nonpharmacological interventions should be implemented more in the clinical routine. Respective barriers for patients, caregivers, clinicians, healthcare systems and research need to be overcome.

The Amplification of Symptoms in the Medically Ill

The mechanism of symptom amplification, developed in the study of somatization, may be helpful in caring for patients with symptoms that, while they have a demonstrable medical basis, are nonetheless disproportionately severe and distressing. Amplified medical symptoms are marked by disproportionate physical suffering, unduly negative thoughts and concerns about them, and elevated levels of health-related anxiety. They are accompanied by extensive and sustained illness behaviors, disproportionate difficulty compartmentalizing them and circumscribing their impact, and consequent problems and dissatisfaction with their medical care. A distinction has long been made between "medically explained" and "medically unexplained" symptoms. However, a more comprehensive view of symptom phenomenology undermines this distinction and places all symptoms along a smooth continuum regardless of cause: Recent findings in cognitive neuroscience suggest that all symptoms-regardless of origin-are processed through convergent pathways. The complete conscious experience of both medically "explained" and "unexplained" symptoms is an amalgam of a viscerosomatic sensation fused with its ascribed salience and the patient's ideas, expectations, and concerns about the sensation. This emerging empirical evidence furnishes a basis for viewing persistent, disproportionately distressing symptoms of demonstrable disease along a continuum with medically unexplained symptoms. Thus, therapeutic modalities developed for somatization and medically unexplained symptoms can be helpful in the care of seriously ill medical patients with amplified symptoms. These interventions include educational groups for coping with chronic illness, cognitive therapies for dysfunctional thoughts, behavioral strategies for maladaptive illness behaviors, psychotherapy for associated emotional distress, and consultation with mental health professionals to assist the primary care physician with difficulties in medical management.

Therapy for insomnia with chronic obstructive pulmonary disease: a randomized trial of components

STUDY OBJECTIVES

To determine efficacy and mechanisms of cognitive behavioral therapy for insomnia (CBT-I) and chronic obstructive pulmonary disease (COPD) education (COPD-ED) on clinical outcomes in adults with concurrent COPD and insomnia.

METHODS

We conducted a 2 × 2 factorial study to test the impact of CBT-I and COPD-ED delivered alone or in combination on severity of insomnia and fatigue, sleep, and dyspnea. Participants were randomized to 1 of 4 groups-group 1: CBT-I + attention control (AC; health videos, n = 27); group 2: COPD-ED + AC, n = 28; group 3: CBT-I + COPD-ED, n = 27; and group 4, AC only, n = 27. Participants received six 75-minute weekly sessions. Dependent variables included insomnia severity, sleep by actigraphy, fatigue, and dyspnea measured at baseline, immediately postintervention, and at 3 months postintervention. Presumed mediators of intervention effects included beliefs and attitudes about sleep, self-efficacy for sleep and COPD, and emotional function.

RESULTS

COPD patients (percent predicted forced expiratory volume in 1 second [FEV1pp] 67% ± 24% [mean ± standard deviation]), aged 65 ± 8 years, with insomnia participated in the study. Insomnia and sleep improved more in patients who received CBT-I than in those who did not, an effect that was sustained at 3 months postintervention and mediated by beliefs and attitudes about sleep. CBT-I was associated with clinically important improvements in fatigue and dyspnea. When CBT-I and COPD-ED were concurrently administered, effects on insomnia, fatigue, and dyspnea were attenuated.

CONCLUSIONS

CBT-I produced significant and sustained decreases in insomnia improved sleep and clinically important improvement in fatigue, and dyspnea. The combination of CBT-I and COPD-ED reduced CBT-I's effectiveness. Further research is needed to understand the mechanisms associated with effects of insomnia therapy on multiple symptoms in COPD.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Name: A Behavioral Therapy for Insomnia Co-existing with COPD; URL: https://clinicaltrials.gov/ct2/show/NCT01973647; Identifier: NCT01973647.

CITATION

Kapella M, Steffen A, Prasad B, et al. Therapy for insomnia with chronic obstructive pulmonary disease: a randomized trial of components. J Clin Sleep Med. 2022;18(12):2763-2774.

'You can't feel what we feel': Multifaceted dyspnoea invisibility in advanced chronic obstructive pulmonary disease examined through interpretative phenomenological analysis

BACKGROUND

More than a symptom, dyspnoea is an existential experience shaping the lives of those afflicted, particularly when its persistence despite maximal pathophysiological treatments makes it pervasive. It is, however, insufficiently appreciated by concerned people themselves, family members, healthcare professionals and the public (dyspnoea invisibility), limiting access to appropriate care and support.

AIM

To provide a better understanding of dyspnoea experiences and its invisibility.

DESIGN

Interpretative phenomenological analysis of data collected prospectively through in-depth semi-structured interviews.

SETTING/PARTICIPANTS

Pulmonary rehabilitation facility of a tertiary care university hospital; 11 people (six men, five women) with severe chronic obstructive pulmonary disease (stages 3 and 4 of the 4-stage international GOLD classification) admitted for immediate post-exacerbation rehabilitation.

RESULTS

We identified several types of dyspnoea invisibility depending on temporality and interlocutors: (1) invisibility as a symptom to oneself; (2) invisibility as a symptom to others; (3) invisibility as an experience that cannot be shared; (4) invisibility as an experience detached from objective measurements; (5) invisibility as an experience that does not generate empathic concern. The notion of invisibility was present in all the identified experiential dimensions of dyspnoea. It was seen as worsening the burden of the disease and as self-aggravating through self-isolation and self-censorship.

CONCLUSIONS

The study confirmed that dyspnoea invisibility is a reality for people with advanced chronic obstructive pulmonary disease. It shows dyspnoea invisibility to be a multifaceted burden. Future research should aim at identifying individual and collective measures to overcome dyspnoea invisibility.

Consistency Evaluation of Two Loading Devices in Measuring the Perception of Dyspnea

Purpose

This study aimed to assess the consistency of hand-held electronic incremental threshold loading device (I-TLD) and traditional constant threshold loading device (C-TLD) in measuring the perception of dyspnea (POD) in humans.

Patients and methods

Thirty-eight patients with stable chronic obstructive pulmonary disease (COPD) and 41 non-COPD subjects were recruited for the study, all of whom were subjected to an external loading breathing test by gradually increasing the inspiratory load starting from 0 to 5, 10, 20, and 30 cmH₂O oral pressure using I-TLD and C-TLD. The Borg score measurement was performed immediately after the loading breath of each level. The linear regression slope a of Borg scores vs percentage of oral pressure from the patients’ maximum represented patients’ POD. The consistency of POD measured by the two devices was analyzed by two Related Samples Wilcoxon test, Spearman correlation analysis, and Bland-Altman analysis.

Results

There was no significant difference in slope a measured by the two devices in all subjects. The Spearman correlation analysis revealed that the slope a measured by the two devices in the inspiratory loading breath test had a significant correlation: in COPD patients, r = 0.678, (p < 0.001) and in non-COPD subjects, r = 0.603, (p < 0.001). For the results of the Bland-Altman analysis of the whole subjects, 3.8% (3/79) points were outside of the 95% LoA confidence interval (CI) (−10.380, 9.457), and the LoA CI was acceptable, which depicted that the two devices were consistent in their estimation.

Conclusion

I-TLD was consistent with C-TLD in measuring POD in COPD patients and non-COPD subjects. I-TLD may be used as an alternative method to replace C-TLD to measure POD in COPD patients and non-COPD subjects.

Loss of Neural Automaticity Contributes to Slower Walking in COPD Patients

The physical impairments (e.g., slower walking speed) in patients with chronic obstructive pulmonary disease (COPD) have been attributed to peripheral characteristics (e.g., muscle atrophy). However, cognitive impairment may compromise motor control including walking automaticity. The objective of this study was to investigate PFC neural activity, evaluated using changes in oxygenated hemoglobin (ΔO₂Hb), during preferred paced walking (PPW) in COPD patients and age-matched controls. The ΔO₂Hb from the left and right dorsolateral PFC was measured using functional near-infrared spectroscopy. Fifteen COPD patients (age: 71 ± 8) and twenty age-matched controls (69 ± 7 years) participated. Two-way mixed ANOVA demonstrated that O₂Hb in both groups decreased during PPW from the start (quintile 1; Q1) to the end (quintile 5; Q5) in the left dorsolateral and medial PFC. Q1 was comprised of the data during the first 20% of the task, while Q5 included data collected in the last 20% of the task duration. PPW duration ranged between 30.0 and 61.4 s in the control group and between 28.6 and 73.0 s in COPD patients. COPD patients demonstrated a higher O₂Hb in Q5 compared to the negative O₂Hb in controls in the right medial and dorsolateral PFC during PPW. PPW velocity was lower in COPD patients compared to controls (1.02 ± 0.22 vs. 1.22 ± 0.14 m/s, p = 0.005). Healthy older controls exhibited automaticity during walking unlike patients with COPD. The lesser decrease in O₂Hb in COPD patients may be attributed to increased executive demands or affect-related cues (e.g., pain or dyspnea) during walking.

Breathing control, brain, and bodily self-consciousness: Toward immersive digiceuticals to alleviate respiratory suffering

Breathing is peculiar among autonomic functions through several characteristics. It generates a very rich afferent traffic from an array of structures belonging to the respiratory system to various areas of the brain. It is intimately associated with bodily movements. It bears particular relationships with consciousness as its efferent motor control can be automatic or voluntary. In this review within the scope of "respiratory neurophysiology" or "respiratory neuroscience", we describe the physiological organisation of breathing control. We then review findings linking breathing and bodily self-consciousness through respiratory manipulations using virtual reality (VR). After discussing the currently admitted neurophysiological model for dyspnea, as well as a new Bayesian model applied to breathing control, we propose that visuo-respiratory paradigms -as developed in cognitive neuroscience- will foster insights into some of the basic mechanisms of the human respiratory system and will also lead to the development of immersive VR-based digital health tools (i.e. digiceuticals).

Psychosocial Intervention in Chronic Obstructive Pulmonary Disease: Meta-Analysis of Randomized Controlled Trials

OBJECTIVE

Many patients with chronic obstructive pulmonary disease (COPD) experience persistent interrelated psychological and physical symptoms despite optimal treatment. Several studies of psychosocial intervention in COPD have been published in recent years. The present study aimed to conduct a quantitative summary of the efficacy of such interventions on psychological and physical outcomes.

METHODS

Two independent raters screened PubMed, PsycINFO, Embase, Web of Science, Cochrane Library, and CINAHL for eligible studies. In all, 35 independent, randomized controlled trials with a total of 3,120 patients with COPD were included, assessed for their methodological quality, and subjected to meta-analytic evaluation.

RESULTS

Meta-analyses revealed small, statistically significant effects of psychosocial intervention on combined psychological (Hedges's g = 0.28; 95%CI: 0.16-0.41) and physical outcomes (g = 0.21; 95%CI: 0.07-0.35) with no indications of publication bias. Supplementary Bayesian meta-analyses provided strong evidence for a non-zero overall effect on psychological outcomes (Bayes factor (BF) = 305) and moderate support for physical outcomes (BF = 6.1). Exploring sources of heterogeneity with meta-regression indicated that older age of patients and longer duration of interventions were associated with smaller effects on psychological outcomes.

CONCLUSIONS

The results support psychosocial intervention as an additional, useful tool in multidisciplinary respiratory care with the potential to improve both psychological and physical outcomes. Future studies are recommended to monitor adverse effects, apply blinding of active control conditions, and determine sample sizes with a priori power calculations.

REGISTRATION

Registered with Prospero (www.crd.york.ac.uk/prospero/) prior to initiation of the literature search (Reg. ID: CRD42020170083).

Dyspnea

The clinical term dyspnea (a.k.a. breathlessness or shortness of breath) encompasses at least three qualitatively distinct sensations that warn of threats to breathing: air hunger, effort to breathe, and chest tightness. Air hunger is a primal homeostatic warning signal of insufficient alveolar ventilation that can produce fear and anxiety and severely impacts the lives of patients with cardiopulmonary, neuromuscular, psychological, and end-stage disease. The sense of effort to breathe informs of increased respiratory muscle activity and warns of potential impediments to breathing. Most frequently associated with bronchoconstriction, chest tightness may warn of airway inflammation and constriction through activation of airway sensory nerves. This chapter reviews human and functional brain imaging studies with comparison to pertinent neurorespiratory studies in animals to propose the interoceptive networks underlying each sensation. The neural origins of their distinct sensory and affective dimensions are discussed, and areas for future research are proposed. Despite dyspnea's clinical prevalence and impact, management of dyspnea languishes decades behind the treatment of pain. The neurophysiological bases of current therapeutic approaches are reviewed; however, a better understanding of the neural mechanisms of dyspnea may lead to development of novel therapies and improved patient care.

The breathing brain: The potential of neural oscillations for the understanding of respiratory perception in health and disease

Dyspnea or breathlessness is a symptom occurring in multiple acute and chronic illnesses, however, the understanding of the neural mechanisms underlying its subjective experience is limited. In this topical review, we propose neural oscillatory dynamics and cross-frequency coupling as viable candidates for a neural mechanism underlying respiratory perception, and a technique warranting more attention in respiration research. With the evidence for the potential of neural oscillations in the study of normal and disordered breathing coming from disparate research fields with a limited history of interdisciplinary collaboration, the main objective of the review was to converge the existing research and suggest future directions. The existing findings show that distinct limbic and cortical activations, as measured by hemodynamic responses, underlie dyspnea, however, the time-scale of these activations is not well understood. The recent findings of oscillatory neural activity coupled with the respiratory rhythm could provide the solution to this problem, however, more research with a focus on dyspnea is needed. We also touch on the findings of distinct spectral patterns underlying the changes in breathing due to experimental manipulations, meditation and disease. Subsequently, we suggest general research directions and specific research designs to supplement the current knowledge using neural oscillation techniques. We argue for the benefits of interdisciplinary collaboration and the converging of neuroimaging and behavioral methods to best explain the emergence of the subjective and aversive individual experience of dyspnea.

Effect of inspiratory muscle training on dyspnea-related kinesiophobia in chronic obstructive pulmonary disease: A randomized controlled trial

BACKGROUND

The major symptom of chronic obstructive pulmonary disease (COPD) is dyspnea, which causes dyspnea-related kinesiophobia resulting in avoidance of activities associated with dyspnea or compensation by reducing the rate of activity. The aim of this study was to assess dyspnea-related kinesiophobia and determine the effect of inspiratory muscle training (IMT) on dyspnea-related kinesiophobia in COPD.

METHODS

Forty COPD subjects were randomly allocated to either the IMT or sham group. Both groups' maximal inspiratory pressure (MIP) was assessed weekly. All patients were instructed to perform the training exercises for 15 min twice a day, 5 days a week for a total of 8 weeks. In the IMT group, intensity was set at 30% of MIP and adjusted according to weekly MIP value. In the sham group, intensity remained constant at 15% of initial MIP. Pulmonary function test (PFT), respiratory muscle strength, 6-min walk test (6 MWT), Breathlessness Beliefs Questionnaire (BBQ), Modified Medical Research Council scale (MMRC), modified Borg scale, Hospital Anxiety and Depression Scale (HADS), Saint George's Respiratory Questionnaire (SGRQ), and COPD Assessment Test (CAT) were assessed before and after the intervention.

RESULTS

BBQ scores ranged from 18 to 51, with mean values in the IMT and sham groups of 39.80 ± 7.62 and 43.00 ± 6.58, respectively. When between-group differences of all outcome scores were compared, there was a statistically significant improvement in the IMT group than in the sham group (p < 0.05). After IMT, statistically significant decreases in BBQ and modified Borg scores were observed in within groups (p ≤ 0.001). These decreases were significantly greater in the IMT group (p ≤ 0.001). MMRC decreased significantly only in the IMT group (p < 0.001). There was a statistically significant increase in PFT values in the IMT group (p = 0.007-0.045), but no difference in the sham group (p = 0.129-0.886). Both groups showed statistically significant improvement in respiratory muscle strength, 6 MWT distance, and CAT score after 8 weeks (p < 0.05). All HADS and SGRQ scores decreased significantly in the IMT group (p < 0.001), whereas only the SGRQ activity score decreased significantly in the sham group (p = 0.017).

CONCLUSIONS

Our study provides data on the presence and level of dyspnea-related kinesiophobia in COPD patients. All patients had BBQ scores higher than 11, indicating dyspnea-related kinesiophobia. IMT reduced BBQ score and improved respiratory function, and exercise capacity. Our results also support the other known benefits of IMT such as reduced dyspnea and symptom perception, decreased anxiety and depression, and improved quality of life.

Breathlessness in COPD: linking symptom clusters with brain activity

Background

Current models of breathlessness often fail to explain disparities between patients' experiences of breathlessness and objective measures of lung function. While a mechanistic understanding of this discordance has thus far remained elusive, factors such as mood, attention and expectation have all been implicated as important modulators of breathlessness. Therefore, we have developed a model to better understand the relationships between these factors using unsupervised machine learning techniques. Subsequently we examined how expectation-related brain activity differed between these symptom-defined clusters of participants.

Methods

A cohort of 91 participants with mild-to-moderate chronic obstructive pulmonary disease (COPD) underwent functional brain imaging, self-report questionnaires and clinical measures of respiratory function. Unsupervised machine learning techniques of exploratory factor analysis and hierarchical cluster modelling were used to model brain–behaviour–breathlessness links.

Results

We successfully stratified participants across four key factors corresponding to mood, symptom burden and two capability measures. Two key groups resulted from this stratification, corresponding to high and low symptom burden. Compared with the high symptom burden group, the low symptom burden group demonstrated significantly greater brain activity within the anterior insula, a key region thought to be involved in monitoring internal bodily sensations (interoception).

Conclusions

This is the largest functional neuroimaging study of COPD to date, and is the first to provide a clear model linking brain, behaviour and breathlessness expectation. Furthermore, it was possible to stratify participants into groups, which then revealed differences in brain activity patterns. Together, these findings highlight the value of multimodal models of breathlessness in identifying behavioural phenotypes and for advancing understanding of differences in breathlessness burden.

Towards individualised treatments for chronic breathlessness with functional neuroimaging: revealing the factors underlying the breathlessness experience in COPDhttps://bit.ly/3a8fXPt

Air Hunger: A Primal Sensation and a Primary Element of Dyspnea

The sensation that develops as a long breath hold continues is what this article is about. We term this sensation of an urge to breathe "air hunger." Air hunger, a primal sensation, alerts us to a failure to meet an urgent homeostatic need maintaining gas exchange. Anxiety, frustration, and fear evoked by air hunger motivate behavioral actions to address the failure. The unpleasantness and emotional consequences of air hunger make it the most debilitating component of clinical dyspnea, a symptom associated with respiratory, cardiovascular, and metabolic diseases. In most clinical populations studied, air hunger is the predominant form of dyspnea (colloquially, shortness of breath). Most experimental subjects can reliably quantify air hunger using rating scales, that is, there is a consistent relationship between stimulus and rating. Stimuli that increase air hunger include hypercapnia, hypoxia, exercise, and acidosis; tidal expansion of the lungs reduces air hunger. Thus, the defining experimental paradigm to evoke air hunger is to elevate the drive to breathe while mechanically restricting ventilation. Functional brain imaging studies have shown that air hunger activates the insular cortex (an integration center for perceptions related to homeostasis, including pain, food hunger, and thirst), as well as limbic structures involved with anxiety and fear. Although much has been learned about air hunger in the past few decades, much remains to be discovered, such as an accepted method to quantify air hunger in nonhuman animals, fundamental questions about neural mechanisms, and adequate and safe methods to mitigate air hunger in clinical situations. © 2021 American Physiological Society. Compr Physiol 11:1449-1483, 2021.

Silent hypoxaemia in COVID-19 patients

The clinical presentation of COVID-19 due to infection with SARS-CoV-2 is highly variable with the majority of patients having mild symptoms while others develop severe respiratory failure. The reason for this variability is unclear but is in critical need of investigation. Some COVID-19 patients have been labelled with 'happy hypoxia', in which patient complaints of dyspnoea and observable signs of respiratory distress are reported to be absent. Based on ongoing debate, we highlight key respiratory and neurological components that could underlie variation in the presentation of silent hypoxaemia and define priorities for subsequent investigation.

Silent hypoxaemia in COVID-19 patients

The clinical presentation of COVID-19 due to infection with SARS-CoV-2 is highly variable with the majority of patients having mild symptoms while others develop severe respiratory failure. The reason for this variability is unclear but is in critical need of investigation. Some COVID-19 patients have been labelled with 'happy hypoxia', in which patient complaints of dyspnoea and observable signs of respiratory distress are reported to be absent. Based on ongoing debate, we highlight key respiratory and neurological components that could underlie variation in the presentation of silent hypoxaemia and define priorities for subsequent investigation.

Hypnosis for the Management of Anxiety and Dyspnea in COPD: A Randomized, Sham-Controlled Crossover Trial

Background

Patients with chronic obstructive pulmonary disease (COPD) are prone to dyspnea, increased respiratory rate and other anxiety-inducing symptoms. Hypnosis constitutes a complementary procedure capable of improving subjective feelings of anxiety.

Objective

Assessing the efficacy of a 15-minute hypnosis intervention for immediate improvement of anxiety in severe COPD patients.

Methods

Twenty-one participants, COPD patients (mean FEV1 < 32.3%), were randomly assigned to two individual sessions in crossover (sham and hypnosis, 24-h washout period, arms: hypnosis-sham [n=11]/sham-hypnosis [n=10]). We tracked pre- and post-intervention anxiety (STAI-6 score) as primary endpoint.

Results

Nineteen (90.5%) participants completed the study. Anxiety diminished significantly after hypnosis (STAI-6 scores −23.8% [SD = 18.4%] hypnosis vs −3.1% [32.8%] sham; χ²=8, P<0.01, Bayes Factor 5.5). Respiratory rate also decreased after hypnosis. Improvements in SpO2 and Borg exertion scores were registered after both conditions.

Conclusion

A 15-minute hypnosis session improved participants’ anxiety and lowered respiratory rate (as opposed to sham). Improvements in anxiety were correlated with an alleviation in respiratory strain. Results imply that hypnosis can contribute to the improvement of anxiety levels and breathing mechanics in severe COPD patients.

Registration Id

ISRCTN10029862.

Identification of Symptom Clusters and Their Influencing Factors in Subgroups of Chinese Patients With Acute Exacerbation of Chronic Obstructive Pulmonary Disease

CONTEXT

Limited studies have identified symptom clusters (SCs) and their risk factors and the relationships with inflammatory biomarkers in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD).

OBJECTIVES

In this study, we aimed to investigate SCs in patients with AECOPD and explore their influencing factors and relationships with inflammatory biomarkers.

METHODS

Data were collected with sociodemographic and disease information questionnaires, and symptoms were measured with the revised Memorial Symptom Assessment Scale. SCs were extracted through exploratory factor analysis. Logistic regression analysis was conducted to explore the risk factors of SCs.

RESULTS

A total of 151 patients were recruited. Two SCs, namely, emotional and respiratory functional SCs, were identified. Logistic regression analysis showed that individuals with high C-reactive protein level, Charlson Comorbidity Index score, and high modified Medical Research Council Dyspnea Scale score were more likely to belong to the high-severity symptom subgroup than to the low-severity symptom group in the emotional SC. The patients with a low body mass index and without or lax inhaled drug therapy exhibited highly prominent predictors of membership in the high-severity symptom group of the respiratory functional SC.

CONCLUSION

Symptoms experienced by patients with AECOPD were grouped into specific clusters. Targeted interventions should be performed based on SCs, and influencing factors and biological mechanisms should be considered when providing individualized approaches and interventions.

Chronic Obstructive Pulmonary Disease: Proprioception Exercises as an Addition to the Rehabilitation Process

Respiratory rehabilitation in patients with chronic obstructive pulmonary disease (COPD) is recognized as a cornerstone for the therapeutic path. Physiotherapy involves physical activity with aerobic and anaerobic exercises, which can improve the patient's symptomatic picture, such as motor function, emotional status (depression and anxiety), and improve the pain perception. The training of proprioception is not included in the structure of the exercises proposed by the Global Initiative for Chronic Obstructive Lung Disease (GOLD). The training of proprioception is a very useful strategy for stimulating the cerebellum, a neurological suffering area in patients with COPD. The cerebellum sorts information about pain and emotions, as well as motor stimuli. The article discusses the need to introduce proprioception in respiratory rehabilitation protocols, highlighting the neurological relationships with the management of comorbidities.

Breathlessness, Anxiety, Depression, and Function-The BAD-F Study: A Cross-Sectional and Population Prevalence Study in Adults

CONTEXT

Breathlessness is associated with depression, but its relationship to anxiety or impaired function is less clear.

OBJECTIVES

This study evaluated associations between chronic breathlessness and anxiety, depression, and functional status in the general population.

METHODS

This cross-sectional study of consenting adults (18 years and older) used an online survey. Quota sampling (n = 3000) was used reflecting the 2016 national census for sex, age, and place of residence. Other data included Four-Item Patient Health Questionnaire for depression and anxiety, the modified Medical Research Council (mMRC) Breathlessness Scale, and the Australia-modified Karnofsky Performance Scale. Multinomial logistic regression assessed predictors.

RESULTS

About 2977 respondents had all relevant scores (female 51.2%; median age 45.0 [range 18-92]). Prevalence of breathlessness (mMRC ≥2) was 2.4%, anxiety 6.0%, depression 2.7%, coexisting anxiety/depression 6.1%, and poorer functional status (Australia-modified Karnofsky Performance Scale ≤60) 1.6%. In multinomial regression, depression, anxiety, and coexisting anxiety/depression were predicted by younger age, longer duration of breathlessness, and poorer functional status. The highest proportions of people with breathlessness were found in the coexisting anxiety/depression group (10.6%) and depression only group (8.8%). Poorest function was in the coexisting anxiety/depression group with 11.6%. The relationship between poorer functional status and coexisting anxiety/depression was significant (odds ratio 0.90; 95% CI 0.89, 0.92). Adjusted odds ratio for breathlessness and depression only was 3.0 (95% CI 1.2, 7.8).

CONCLUSION

Clinically important breathlessness (mMRC ≥2) was associated with depression, anxiety, and coexisting anxiety/depression. Poorer function that is associated with psychological morbidity in the general population requires further research.

Brain Activations to Dyspnea in Patients With COPD

We compared the perception and neural processing of respiratory sensations between 20 COPD patients and 20 healthy controls by means of respiratory-related evoked potentials (RREP) in the electroencephalogram (EEG). RREPs were induced by short inspiratory occlusions while 129-channel EEG was measured. COPD patients rated the occlusions as more intense and unpleasant (p's < 0.001) and showed higher mean amplitudes for the RREP components P1 (p = 0.0004), N1 (p = 0.024), P2 (p = 0.019), and P3 (p = 0.018). Our results indicate that COPD patients demonstrate greater perception and neural processing of respiratory sensations, which presumably reflects the highly aversive and attention-demanding character of these sensations for COPD patients.

Transcriptomic Characterization of the Human Insular Cortex and Claustrum

The insular cortex has been linked to a multitude of functions. In contrast, the nearby claustrum is a densely connected subcortical region with unclear function. To view the insula-claustrum region from the molecular perspective we analyzed the transcriptomic profile of these areas in six adult and four fetal human brains. We identified marker genes with specific expression and performed transcriptome-wide tests for enrichment of biological processes, molecular functions, and cellular components. In addition, specific insular and claustral expression of genes pertaining to diseases, addiction, and depression was tested. At the anatomical level, we used brain-wide analyses to determine the specificity of our results and to determine the transcriptomic similarity of the insula-claustrum region. We found UCMA to be the most significantly enriched gene in the insular cortex and confirmed specific expression of NR4A2, NTNG2, and LXN in the claustrum. Furthermore, the insula was found to have enriched expression of genes associated with mood disorders, learning, cardiac muscle contraction, oxygen transport, glutamate and dopamine signaling. Specific expression in the claustrum was enriched for genes pertaining to human immunodeficiency virus (HIV), severe intellectual disability, epileptic encephalopathy, intracellular transport, spine development, and macroautophagy. We tested for enrichment of genes related to addiction and depression, but they were generally not highly specific to the insula-claustrum region. Exceptions include high insular expression of genes linked to cocaine abuse and genes associated with ever smoking in the claustrum. Brain-wide, we find that markers of the adult claustrum are most specifically expressed in the fetal and adult insula. Altogether, our results provide a novel molecular perspective on the unique properties of the insula and claustrum.

The effect of anxiety on brain activation patterns in response to inspiratory occlusions: an fMRI study

Respiratory sensations such as breathlessness are prevalent in many diseases and are amplified by increased levels of anxiety. Cortical activation in response to inspiratory occlusions in high- and low-anxious individuals was found different in previous studies using the respiratory-related evoked potential method. However, specific brain areas showed different activation patterns remained unknown in these studies. Therefore, the purpose of this study was to compare cortical and subcortical neural substrates of respiratory sensation in response to inspiratory mechanical occlusion stimuli between high- and low-anxious individuals using functional magnetic resonance imaging (fMRI). In addition, associations between brain activation patterns and levels of anxiety, and breathlessness were examined. Thirty-four (17 high- and 17 low-anxious) healthy non-smoking adults with normal lung function completed questionnaires on anxiety (State Trait Anxiety Inventory - State), and participated in a transient inspiratory occlusion fMRI experiment. The participants breathed with a customized face-mask while respiration was repeatedly interrupted by a transient inspiratory occlusion of 150-msec, delivered every 2 to 4 breaths. Breathlessness was assessed by self-report. At least 32 occluded breaths were collected for data analysis. The results showed that compared to the low-anxious group, the high-anxious individuals demonstrated significantly greater neural activations in the hippocampus, insula, and middle cingulate gyrus in response to inspiratory occlusions. Moreover, a significant relationship was found between anxiety levels and activations of the right inferior parietal gyrus, and the right precuneus. Additionally, breathlessness levels were significantly associated with activations of the bilateral thalamus, bilateral insula and bilateral cingulate gyrus. The above evidences support stronger recruitment of emotion-related cortical and subcortical brain areas in higher anxious individuals, and thus these areas play an important role in respiratory mechanosensation mediated by anxiety.

Contributions of cardiovascular risk and smoking to chronic obstructive pulmonary disease (COPD)-related changes in brain structure and function

Background

Brain damage and cardiovascular disease are extra-pulmonary manifestations of chronic obstructive pulmonary disease (COPD). Cardiovascular risk factors and smoking are contributors to neurodegeneration. This study investigates whether there is a specific, COPD-related deterioration in brain structure and function independent of cardiovascular risk factors and smoking.

Materials and methods

Neuroimaging and clinical markers of brain structure (micro- and macro-) and function (cognitive function and mood) were compared between 27 stable COPD patients (age: 63.0±9.1 years, 59.3% male, forced expiratory volume in 1 second [FEV1]: 58.1±18.0% pred.) and 23 non-COPD controls with >10 pack years smoking (age: 66.6±7.5 years, 52.2% male, FEV1: 100.6±19.1% pred.). Clinical relationships and group interactions with brain structure were also tested. All statistical analyses included correction for cardiovascular risk factors, smoking, and aortic stiffness.

Results

COPD patients had significantly worse cognitive function (p=0.011), lower mood (p=0.046), and greater gray matter atrophy (p=0.020). In COPD patients, lower mood was associated with markers of white matter (WM) microstructural damage (p<0.001), and lower lung function (FEV1/forced vital capacity and FEV1) with markers of both WM macro (p=0.047) and microstructural damage (p=0.028).

Conclusion

COPD is associated with both structural (gray matter atrophy) and functional (worse cognitive function and mood) brain changes that cannot be explained by measures of cardiovascular risk, aortic stiffness, or smoking history alone. These results have important implications to guide the development of new interventions to prevent or delay progression of neuropsychiatric comorbidities in COPD. Relationships found between mood and microstructural abnormalities suggest that in COPD, anxiety, and depression may occur secondary to WM damage. This could be used to better understand disabling symptoms such as breathlessness, improve health status, and reduce hospital admissions.

The influence of affective state on respiratory muscle activity

Measures of neural respiratory drive through the use of electromyography of the parasternal intercostal muscles (EMGpara) are accurate markers of respiratory load and are reflective of pulmonary function. A previous observation of a significant reduction in EMGpara from a first to second measurement occasion was attributed to participants' acclimatization to the laboratory environment and a reduction in anxiety. This study therefore aimed to investigate whether manipulation of participants' affective state would influence EMGpara and related variables. Healthy adult participants underwent measurement of EMGpara and respiratory flow and volume during exposure to four conditions: no stimulus, music, and tense and calm videos. Respiratory rate (RR), raw neural respiratory drive index (rawNRDI, the product of EMGpara in microvolts and RR) and minute ventilation (VE) differed significantly across conditions: RR and VE were significantly higher in the tense condition than all other conditions (all P<0·05); rawNRDI was higher in the tense compared to the calm video condition (P = 0·03). There was also a significant relationship between EMGpara and subjective tension ratings (measured via visual analogue scale) in the tense condition (Spearman's rho = 0·508, P = 0·016), with multivariate modelling indicating significant interactions between rawNRDI and subjective ratings of both tension and calmness. This suggests that anxiety could contribute to elevated respiratory muscle activity and ventilation. Greater consideration should be given to the influence of anxiety when undertaking measurement of respiratory muscle activity to ensure data accurately represent underlying respiratory load.

European Respiratory Society International Congress 2018: Allied Respiratory Professionals' report of highlighted sessions

This article provides an overview of outstanding sessions that were supported by Assembly 9 during the recent European Respiratory Society International Congress in Paris, France. Session content was mainly targeted at allied health professionals such as respiratory physiologists, respiratory physiotherapists and respiratory nurses. Recent developments and novel findings related to pulmonary function testing, respiratory muscle function assessments and treatment, and multidimensional and multidisciplinary approaches to the assessment and management of dyspnoea were the focus of these sessions and are summarised here.

An overview of outstanding sessions that were supported by Assembly 9 during the 2018 European Respiratory Society International Congress in Paris, France.http://ow.ly/OO8P30mXs3q

The Effect of Pulmonary Rehabilitation in Mountain Environment on Exercise Capacity and Quality of Life in Patients with Chronic Obstructive Pulmonary Disease (COPD) and Chronic Bronchitis

BACKGROUND We aimed to test the effectiveness of the pulmonary rehabilitation in a mountain environment on the pulmonary function, physical performance, dyspnea, affective factors, and quality of life (QoL) in patients with chronic obstructive pulmonary disease (COPD) and chronic bronchitis (CB), as well as to determine predictors of clinical improvement. MATERIAL AND METHODS 128 consecutive patients (90 diagnosed with COPD and 38 diagnosed with CB) underwent comprehensive pulmonary rehabilitation for a duration of 3 weeks in one of 3 mountain health resorts in the High Tatras. The examination included spirometry (FEV1 and FEV1/FVC), 6-minute walk test (6MWT), Borg scale of dyspnea, and assessment of depression (Zung score), anxiety (Beck score), and QoL using the SF-36 scales. RESULTS After the study intervention, all patients in both monitored groups demonstrated significant improvements in objective measurements in which large treatment effect was achieved (for FEV1 η²=0.218, for 6MWT η²=0.771). Similarly, in subjective measurements a large effect was achieved (for the Beck score: η²=0.599, for the Zung score: η²=0.536). QoL improved after the intervention in all the monitored SF-36 scales in both groups (P<0.001 for all). In patients with COPD, the improvement of exercise capacity was positively correlated with baseline 6MWT and FEV1, and negatively with the Beck anxiety score and the Borg dyspnea score, whereas, only improvement in the mental summary component of QoL was negatively correlated with baseline 6MWT and FEV1 (P<0.05 for all). CONCLUSIONS Rehabilitation in a mountain environment has proven to be effective in both the reported diagnoses of COPD and CB. Improvements in both functional and subjective indicators were observed. These findings support the use of this treatment modality.

The impact of dyspnea and threat of dyspnea on error processing

Dyspnea (breathlessness) is a threatening and aversive bodily sensation and a major symptom of various diseases. It has been suggested to impair several aspects of functioning in affected patients, but experimental proof for this assumption is widely absent. Error processing is an important domain of functioning and has intensively been studied using electrophysiological measures. Specifically, the error-related negativity (ERN) has been suggested to reflect early performance monitoring and error detection, while the error positivity (Pe) has been linked to subsequent error awareness. So far, little is known about the effects of anticipated or perceived dyspnea on error processing. Therefore, in 49 healthy participants, we studied the effects of experimentally induced dyspnea and threat of dyspnea on the ERN/Pe and behavioral task performance. Participants performed the arrowhead version of the flanker task during three experimental conditions: an unloaded baseline condition, a dyspnea condition, and a threat of dyspnea condition. Dyspnea was induced by breathing through inspiratory resistive loads, while high-density EEG was continuously measured. No differences in task performance (reaction times, error rates) and ERN mean amplitudes were found between conditions. However, mean amplitudes for the Pe differed between conditions with smaller Pe amplitudes during threat of dyspnea compared to baseline and dyspnea conditions, with the latter two conditions showing no difference. These results may suggest that threat of dyspnea, but not dyspnea itself, reduces error awareness, while both seem to have no impact on early error processing and related behavioral performance.

Breathlessness amplifies amygdala responses during affective processing

Breathlessness is an aversive symptom in many prevalent somatic and psychiatric diseases and is usually experienced as highly threatening. It is strongly associated with negative affect, but the underlying neural processes remain poorly understood. Therefore, using fMRI, the present study examined the effects of breathlessness on the neural processing of affective visual stimuli within candidate brain areas including the amygdala, insula, and anterior cingulate cortex (ACC). During scanning, 42 healthy volunteers, mean (SD) age: 29.0 (6.0) years, 14 female, were presented with affective picture series of negative, neutral, and positive valence while experiencing either no breathlessness (baseline conditions) or resistive-load induced breathlessness (breathlessness conditions). Respiratory measures and self-reports suggested successful induction of breathlessness and affective experiences. Self-reports of breathlessness intensity and unpleasantness were significantly higher during breathlessness conditions, mean (SD): 45.0 (16.6) and 32.3 (19.8), as compared to baseline conditions, mean (SD): 1.9 (3.0) and 2.9 (5.5). Compared to baseline conditions, stronger amygdala activations were observed during breathlessness conditions for both negative and positive affective picture series relative to neutral picture series, while no such effects were observed in insula and ACC. The present findings demonstrate that breathlessness amplifies amygdala responses during affective processing, suggesting an important role of the amygdala for mediating the interactions between breathlessness and affective states.

Hippocampal metabolites in asthma and their implications for cognitive function

Emerging research indicates that individuals with asthma have an increased risk of cognitive impairment, yet the associations of asthma with neural correlates of memory remain relatively unknown. The hippocampus is the predominant neural structure involved in memory, and alterations in the hippocampal metabolic profile are observed in individuals with mild cognitive impairment. We therefore hypothesized that individuals with asthma may have altered hippocampal metabolites compared to healthy controls. Structural magnetic resonance imaging (sMRI) and proton magnetic resonance spectroscopy (1H-MRS) were used to compare hippocampal volume and metabolites of otherwise healthy adults with and without asthma (N = 40), and to study the association of these measures with cognitive function and asthma-related variables. Participants underwent 3-Tesla sMRI and 1H-MRS, with the volume of interest placed in the left hippocampus to measure levels of N-acetylaspartate (NAA), glutamate (Glu), creatine (Cr), and myo-inositol (MI), as indicators of neuronal viability, cellular activity, cellular energy reserve, as well as glial activation. Individuals with asthma had lower hippocampal NAA compared to healthy controls. For all participants, poorer cognitive function was associated with reduced NAA and Glu. For individuals with asthma, poorer cognitive function was associated with reduced disease control. Additionally, short-acting rescue bronchodilator use was associated with significantly lower NAA, and Glu, whereas inhaled corticosteroid use was related to significantly higher Cr and in tendency higher NAA and Glu. All findings controlled for left hippocampal volume, which was not different between groups. These findings highlight that asthma and/or its treatment may affect hippocampal chemistry. It is possible that the observed reductions in hippocampal metabolites in younger individuals with asthma may precede cognitive and hippocampal structural deficits observed in older individuals with asthma.