Dyspnea and Emotion

Dyspnea induced by inspiratory loading limits dual-tasking in healthy young adults

OBJECTIVES

Dyspnea is a common and multidimensional experience of healthy adults and those with respiratory disorders. Due to its neural processing, it may limit or interfere with cognition, which may be examined with a dual-task paradigm. The aim of this study was to compare single-task performance of Stroop Colour and Word Test (SCWT) or inspiratory threshold loading (ITL) to their combined dual-task performance. Secondly, whether mood was related to dyspnea or cognitive performance was also evaluated.

MATERIALS & METHODS

A virtual pre-post design examined single (SCWT and ITL) and dual-task (SCWT+ITL) performance. For ITL, a Threshold Trainer™ was used to elicit a "somewhat severe" rating of dyspnea. The SCWT required participants to indicate whether a colour-word was congruent or incongruent with its semantic meaning. The Depression, Anxiety and Stress Scale-21 (DASS-21) was completed to assess mood. Breathing frequency, Borg dyspnea rating, and breathing endurance time were ascertained.

RESULTS

Thirty young healthy adults (15F, 15M; median age = 24, IQR [23-26] years) completed the study. SCWT+ITL had lower SCWT accuracy compared to SCWT alone (98.6%, [97.1-100.0] vs 99.5%, [98.6-100.0]; p = 0.009). Endurance time was not different between ITL and SCWT+ITL (14.5 minutes, [6.9-15.0]) vs 13.7 minutes, [6.1-15.0]; p = 0.59). DASS-21 scores positively correlated with dyspnea scores during ITL (rho = 0.583, p<0.001) and SCWT+ITL (rho = 0.592, p<0.001).

CONCLUSIONS

ITL significantly reduced dual-task performance in healthy young adults. Lower mood was associated with greater perceived dyspnea during single and dual-task ITL. Considering the prevalence of dyspnea in respiratory disorders, the findings of this dual task paradigm warrant further exploration to inform dyspnea management during daily activities.

Mental Experiences in Wild Animals: Scientifically Validating Measurable Welfare Indicators in Free-Roaming Horses

The mental experiences of animals are what characterises their welfare status. The Five Domains Model for assessing welfare aligns with the understanding that physical and mental states are linked. Following measurement of indicators within each of the four physical/functional Domains (1. Nutrition; 2. Physical environment; 3. Health; and 4. Behavioural interactions), the anticipated negative or positive affective consequences (mental experiences) are cautiously inferred and assigned to Domain 5. Those inferences derive credibility from validated knowledge of the underlying systems of physiology, neurophysiology, neuroethology and affective neuroscience. Any indicators used for assessing welfare need to be scientifically validated. This requires, firstly, evidence of the links between a measurable/observable indicator and the physical/functional impact (in Domains 1 to 4), and secondly, a demonstrable relationship between the physical/functional impact and the mental experience it is inferred the indicators reflect (in Domain five). This review refers to indicators of physical/functional states in Domains 1 to 4, which have been shown to be measurable in free-roaming wild horses, and then evaluates the scientific evidence linking them to inferred mental experiences in Domain 5. This is the first time that the scientific evidence validating a comprehensive range of welfare indicators has been synthesised in this way. Inserting these indicators into the Five Domains Model enables transparently justifiable assessment and grading of welfare status in free-roaming horses.

Randomized Controlled Study Evaluating Efficiency of Low Intensity Transcranial Direct Current Stimulation (tDCS) for Dyspnea Relief in Mechanically Ventilated COVID-19 Patients in ICU: The tDCS-DYSP-COVID Protocol

The severe respiratory distress syndrome linked to the new coronavirus disease (COVID-19) includes unbearable dyspneic suffering which contributes to the deterioration of the prognosis of patients in intensive care unit (ICU). Patients are put on mechanical ventilation to reduce respiratory suffering and preserve life. Despite this mechanical ventilation, most patients continue to suffer from dyspnea. Dyspnea is a major source of suffering in intensive care and one of the main factors that affect the prognosis of patients. The development of innovative methods for its management, especially non-drug management is more than necessary. In recent years, numerous studies have shown that transcranial direct current stimulation (tDCS) could modulate the perception of acute or chronic pain. In the other hand, it has been shown that the brain zones activated during pain and dyspnea are close and/or superimposed, suggesting that brain structures involved in the integration of aversive emotional component are shared by these two complex sensory experiences. Therefore, it can be hypothesized that stimulation by tDCS with regard to the areas which, in the case of pain have activated one or more of these brain structures, may also have an effect on dyspnea. In addition, our team recently demonstrated that the application of tDCS on the primary cortical motor area can modulate the excitability of the respiratory neurological pathways. Indeed, tDCS in anodal or cathodal modality reduced the excitability of the diaphragmatic cortico-spinal pathways in healthy subjects. We therefore hypothesized that tDCS could relieve dyspnea in COVID-19 patients under mechanical ventilation in ICU. This study was designed to evaluate effects of two modalities of tDCS (anodal and cathodal) vs. placebo, on the relief of dyspnea in COVID-19 patients requiring mechanical ventilation in ICU. Trial Registration: This protocol is derived from the tDCS-DYSP-REA project registered on ClinicalTrials.gov NCT03640455. It will however be registered under its own NCT number.

Common causes of dyspnoea in athletes: a practical approach for diagnosis and management

Key points

Educational aims

Dyspnoea during exercise is a common chief complaint in athletes and active individuals. It is not uncommon for dyspnoeic athletes to be diagnosed with asthma, “exercise-induced asthma” or exercise-induced bronchoconstriction based on their symptoms, but this strategy regularly leads to misdiagnosis and improper patient management. Dyspnoea during exercise can ultimately be caused by numerous respiratory and nonrespiratory conditions, ranging from nonpathological to potentially fatal in severity. As, such it is important for healthcare providers to be familiar with the many factors that can cause dyspnoea during exercise in seemingly otherwise-healthy individuals and have a general understanding of the clinical approach to this patient population. This article reviews common conditions that ultimately cause athletes to report dyspnoea and associated symptoms, and provides insight for developing an efficient diagnostic plan.

Dyspnoea, fatigue and underperformance are often interrelated symptoms in athletes, and may have various causeshttp://ow.ly/4nsYnk

Introducing breathlessness as a significant animal welfare issue

Breathlessness is a negative affective experience relating to respiration, the animal welfare significance of which has largely been underestimated in the veterinary and animal welfare sciences. In this review, we draw attention to the negative impact that breathlessness can have on the welfare of individual animals and to the wide range of situations in which mammals may experience breathlessness. At least three qualitatively distinct sensations of breathlessness are recognised in human medicine--respiratory effort, air hunger and chest tightness--and each of these reflects comparison by cerebral cortical processing of some combination of heightened ventilatory drive and/or impaired respiratory function. Each one occurs in a variety of pathological conditions and other situations, and more than one may be experienced simultaneously or in succession. However, the three qualities vary in terms of their unpleasantness, with air hunger reported to be the most unpleasant. We emphasise the important interplay among various primary stimuli to breathlessness and other physiological and pathophysiological conditions, as well as animal management practices. For example, asphyxia/drowning of healthy mammals or killing those with respiratory disease using gases containing high carbon dioxide tensions is likely to lead to severe air hunger, while brachycephalic obstructive airway syndrome in modern dog and cat breeds increases respiratory effort at rest and likely leads to air hunger during exertion. Using this information as a guide, we encourage animal welfare scientists, veterinarians, laboratory scientists, regulatory bodies and others involved in evaluations of animal welfare to consider whether or not breathlessness contributes to any compromise they may observe or wish to avoid or mitigate.

The affective dimension of dyspnea improves in a dyspnea self-management program with exercise training

CONTEXT

The perception of dyspnea includes both sensory and affective dimensions that are shaped by emotions and psychological, social, and environmental experiences. Previous investigators have studied either measurement or strategies to decrease the affective dimension with laboratory-induced dyspnea. Few have reported the effect of a therapeutic clinical intervention on the affective dimension of dyspnea.

OBJECTIVES

(1) To evaluate the effects of three different versions of a dyspnea self-management program (DM) on the affective dimension of dyspnea, measured by dyspnea-related anxiety (DA) and dyspnea-related distress (DD); and (2) to determine the stability of DA and DD over two baseline incremental treadmill tests (ITTs).

METHODS

Participants with chronic obstructive pulmonary disease were randomly assigned to three 12 month DMs with varying doses of supervised exercise (DM, DM-Exposure, and DM-Training). The measurements of the affective dimension, DA and DD, were rated during ITTs on two baseline days and at two, six, and 12 months. Changes over time in DA and DD were analyzed using linear mixed-effects models.

RESULTS

Participants in the DM-Training group who received 24 nurse-coached exercise sessions had significantly greater reductions in DA and DD compared with those who had four exercise sessions (DM-Exposure) or only received a home-walking program (DM). Reductions in DA and DD in the DM-Training group were only maintained through six months. There were no significant differences in ratings of DA and DD at end between the two baseline ITTs.

CONCLUSION

These findings provide initial support for the positive impact of a self-management program with nurse-coached exercise on the affective dimension of dyspnea. Further investigation of interventions that target the affective dimension in addition to the sensory dimension of dyspnea should be encouraged.

Evidence for cognitive-behavioral strategies improving dyspnea and related distress in COPD

BACKGROUND

Dyspnea is a complex, prevalent, and distressing symptom of chronic obstructive pulmonary disease (COPD) associated with decreased quality of life, significant disability, and increased mortality. It is a major reason for referral to pulmonary rehabilitation.

METHODS

We reviewed 23 COPD studies to examine the evidence for the effectiveness of cognitive-behavioral strategies for relieving dyspnea in COPD.

RESULTS

Preliminary evidence from randomized controlled trials exists to support cognitive- behavioral strategies, used with or without exercise, for relieving sensory and affective components of dyspnea in COPD. Small to moderate treatment effects for relieving dyspnea were noted for psychotherapy (effect size [ES] = 0.08-0.25 for intensity; 0.26-0.65 for mastery) and distractive auditory stimuli (ES = 0.08-0.33 for intensity; 0.09 to -0.61 for functional burden). Small to large dyspnea improvements resulted from yoga (ES = 0.2-1.21 for intensity; 0.67 for distress; 0.07 for mastery; and -8.37 for functional burden); dyspnea self-management education with exercise (ES = -0.14 to -1.15 for intensity; -0.62 to -0.69 for distress; 1.04 for mastery; 0.14-0.35 for self-efficacy); and slow-breathing exercises (ES = -0.34 to -0.83 for intensity; -0.61 to -0.80 for distress; and 0.62 for self-efficacy). Cognitive-behavioral interventions may relieve dyspnea in COPD by (1) decreasing sympathetic nerve activity, dynamic hyperinflation, and comorbid anxiety, and (2) promoting arterial oxygen saturation, myelinated vagus nerve activity, a greater exercise training effect, and neuroplasticity.

CONCLUSION

While evidence is increasing, additional randomized controlled trials are needed to evaluate the effectiveness of psychosocial and self-management interventions in relieving dyspnea, in order to make them more available to patients and to endorse them in official COPD, dyspnea, and pulmonary rehabilitation practice guidelines. By relieving dyspnea and related anxiety, such interventions may promote adherence to exercise programs and adaptive lifestyle change.

Dyspnea and emotional states in health and disease

Anxiety and depression can increase the intensity of dyspnea out of proportion to the impairment in cardiorespiratory function and may contribute to the degree of disability associated with dyspnea. The effect of anxiety/depression on the sensory and affective components of reported dyspnea in patients with respiratory disorders might be of particular importance in improving the accuracy of the diagnostic process. However, the exact cause-relationship between dyspnea and anxiety/depression are unclear. A multidimensional model of dyspnea subsuming sensory components (i.e. intensity and quality) and affective components has recently been proposed. Affective responses drive patients to seek treatment which can cause them to alter their lifestyle to avoid dyspnea. Brain imaging techniques help identify distinct cortical structures involved in processing the discrete components of dyspnea.

Behavioral medicine approaches to chronic obstructive pulmonary disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a prevalent respiratory disease and associated with considerable individual and socioeconomic burden. Recent research started examining the role of psychosocial factors for course and management of the disease.

PURPOSE

This review provides an overview on recent findings on psychosocial factors and behavioral medicine approaches in COPD.

RESULTS

Research has identified several important psychosocial factors and effective behavioral medicine interventions in COPD. However, there is considerable need for future research in this field.

CONCLUSIONS

Although beneficial effects of some behavioral medicine interventions have been demonstrated in COPD, future research efforts are necessary to study the effects of distinct components of these interventions, to thoroughly examine promising but yet not sufficiently proven interventions, and to develop new creative interventions.

Gaps in the evidence base of opioids for refractory breathlessness. A future work plan?

Breathlessness or "shortness of breath," medically termed dyspnea, remains a devastating problem for many people and those who care for them. As a treatment intervention, administration of opioids to relieve breathlessness is an area where progress has been made with the development of an evidence base. As evidence in support of opioids has accumulated, so has our collective understanding about trial methodology, research collaboration, and infrastructure that is crucial to generate reliable research results for palliative care clinical settings. Analysis of achievements to date and what it takes to accomplish these studies provides important insights into knowledge gaps needing further research and practical insight into design of pharmacological and nonpharmacological intervention trials in breathlessness and palliative care. This article presents the current understanding of opioids for treating breathlessness, what is still unknown as priorities for future research, and highlights methodological issues for consideration in planned studies.

Quality of recalled dyspnoea is different from exercise-induced dyspnoea: an experimental study

QUESTIONS

Are volunteered and endorsed descriptors of recalled breathlessness consistent with descriptors of exercise-induced breathlessness? Are volunteered and endorsed descriptors of exercise-induced breathlessness consistent?

DESIGN

Within-participant, repeated measures, experimental study.

PARTICIPANTS

57 people with symptomatic chronic respiratory disease aged 71 years.

INTERVENTION

There were three conditions. The first was recalled breathlessness. Two conditions of exercise-induced breathlessness were created by getting the participants to undertake the 6-min Walk Test twice (breathlessness 1 and 2).

OUTCOME MEASURES

Descriptors of breathlessness were volunteered (where participants' used their own words) or endorsed (from a pre-existing list of 15 breathlessness statements).

RESULTS

Emotive descriptors made up 65% of recalled descriptors compared with 11% of exercise-induced descriptors, whereas physical descriptors made up 35% of recalled descriptors compared with 89% of exercise-induced descriptors. Of the 237 potential language pairs volunteered to describe recalled and exercise-induced breathlessness 1, only 27 (11%) were identical whereas of the 171 potential language pairs endorsed as describing recalled and exercise-induced breathlessness 1, 66 (39%) were identical. Of the 175 potential language pairs of descriptors volunteered to describe exercise-induced breathlessness 1 and 2, 72 (41%) were identical whereas of the 153 potential language pairs endorsed as describing exercise-induced breathlessness 1 and 2, 71 (46%) were identical.

CONCLUSION

The language used to describe exercise-induced breathlessness immediately after two walking challenges was similar. However, descriptions of recalled breathlessness did not consistently match descriptions of exercise-induced breathlessness, which may reflect the different contexts under which breathlessness was recalled and induced.

Opioids depress cortical centers responsible for the volitional control of respiration

Respiratory depression limits provision of safe opioid analgesia and is the main cause of death in drug addicts. Although opioids are known to inhibit brainstem respiratory activity, their effects on cortical areas that mediate respiration are less well understood. Here, functional magnetic resonance imaging was used to examine how brainstem and cortical activity related to a short breath hold is modulated by the opioid remifentanil. We hypothesized that remifentanil would differentially depress brain areas that mediate sensory-affective components of respiration over those that mediate volitional motor control. Quantitative measures of cerebral blood flow were used to control for hypercapnia-induced changes in blood oxygen level-dependent (BOLD) signal. Awareness of respiration, reflected by an urge-to-breathe score, was profoundly reduced with remifentanil. Urge to breathe was associated with activity in the bilateral insula, frontal operculum, and secondary somatosensory cortex. Localized remifentanil-induced decreases in breath hold-related activity were observed in the left anterior insula and operculum. We also observed remifentanil-induced decreases in the BOLD response to breath holding in the left dorsolateral prefrontal cortex, anterior cingulate, the cerebellum, and periaqueductal gray, brain areas that mediate task performance. Activity in areas mediating motor control (putamen, motor cortex) and sensory-motor integration (supramarginal gyrus) were unaffected by remifentanil. Breath hold-related activity was observed in the medulla. These findings highlight the importance of higher cortical centers in providing contextual awareness of respiration that leads to appropriate modulation of respiratory control. Opioids have profound effects on the cortical centers that control breathing, which potentiates their actions in the brainstem.

The impact of affective states on the perception of dyspnea in patients with chronic obstructive pulmonary disease

Dyspnea is the cardinal symptom of chronic obstructive pulmonary disease (COPD). Affective states can profoundly impact upon the perception of dyspnea, but little is known about this relationship in patients with COPD. We, therefore, examined the impact of viewing positive versus negative affective picture series on perceived dyspnea during two cycle ergometer exercise tests (CEET) in 30 patients with COPD. Whereas cardiopulmonary measures indicated comparable exercise intensity during both CEETs, parallel viewing of negative affective pictures resulted in increased dyspnea ratings compared to positive affective pictures. Regression analyses showed that only during positive picture viewing increases in the affective unpleasantness of dyspnea, but not in the sensory intensity of dyspnea, during CEETs were predictive of greater dyspnea during everyday activities and reduced health-related quality of life. The results suggest that negative affective states increase perceived dyspnea in patients with COPD and underline the importance of targeting the affect-dyspnea-relationship in this patient group.

Down-regulation of insular cortex responses to dyspnea and pain in asthma

RATIONALE

Dyspnea is the impairing cardinal symptom of asthma but its accurate perception is also crucial for timely initiation of treatment. However, the underlying brain mechanisms of perceived dyspnea in patients with asthma are unknown.

OBJECTIVES

To study brain mechanisms of dyspnea in asthma.

METHODS

By using functional magnetic resonance imaging we compared the neuronal responses to experimentally induced dyspnea in patients with asthma and healthy controls. These brain activations were compared with neuronal responses evoked by pain to study neuronal generalization processes to another, similarly unpleasant, physiological sensation.

MEASUREMENTS AND MAIN RESULTS

While lying in the scanner, fourteen patients with mild-to-moderate asthma and fourteen matched healthy controls repeatedly underwent conditions of mild dyspnea, severe dyspnea, mild pain and severe pain. Dyspnea was induced by resistive loaded breathing. Heat pain of similar intensity was induced by a contact thermode. Whereas the sensory intensity of both sensations was rated similar by patients and controls, ratings of the affective unpleasantness of dyspnea and pain were reduced in patients. This perceptual difference was mirrored by reduced insular cortex activity, but increased activity in the periaqueductal gray (PAG) in patients during both increased dyspnea and pain. Connectivity analyses showed that asthma-specific down-regulation of the insular cortex during dyspnea and pain was moderated by increased PAG activity.

CONCLUSIONS

The results suggest a down-regulation of affect-related insular cortex activity by the PAG during perceived dyspnea and pain in patients with asthma. This might represent a neuronal habituation mechanism reducing the affective unpleasantness of dyspnea in asthma, which generalizes to other unpleasant physiological sensations such as pain.