Attentional distraction reduces the affective but not the sensory dimension of perceived dyspnea

The impact of sport on the physical, psychological and social wellbeing of people with chronic breathlessness: A mixed-methods systematic review

OBJECTIVE

Sport participation may have quality-of-life benefits for people with chronic breathlessness; however, its feasibility and impact on health are unknown. We aimed to synthesise the scientific literature concerning the impact of sport for people with chronic breathlessness.

DATA SOURCES

Searches of MEDLINE, CINAHL, PsycINFO, Embase, SPORTDiscus and Google Scholar were conducted (May 2023).

REVIEW METHODS

Studies were included if they assessed the impact of sport with participants who were likely to suffer from chronic breathlessness due to an underlying condition (e.g. severe asthma, heart failure). A convergent-segregated approach to synthesis in accordance with the JBI methodology for mixed-methods reviews was utilised, including meta-analytic and meta-aggregation analyses.

RESULTS

A total of 22 studies met the inclusion criteria. Studies sampled 1017 participants from 13 different countries, with sample sizes ranging from 5 to 185. Causes of breathlessness consisted of chronic respiratory diseases (9 studies) and coronary heart disease (13 studies). Design-wise, 18 reported quantitative methods, 3 qualitative, and 1 mixed-methods.

CONCLUSIONS

Sports were well-adhered to with only minor/unrelated adverse events reported. Improvements in exercise capacity were observed although there was no impact on health-related quality of life. Other quantitative outcomes extracted varied widely across studies, making it difficult to draw firm conclusions. Participation in sports was reliably recorded at intensity consistent with moderate-to-vigorous activity despite being self-paced. Qualitative themes emphasised the positive elements of sport participation, namely, social cohesion, the capacity to incorporate culture, and the idea that participation is enjoyable rather than a necessary chore to maintain one's health.

Symptom Assessment for Mechanically Ventilated Patients: Principles and Priorities: An Official American Thoracic Society Workshop Report

Mechanically ventilated patients experience many adverse symptoms, such as anxiety, thirst, and dyspnea. However, these common symptoms are not included in practice guideline recommendations for routine assessment of mechanically ventilated patients. An American Thoracic Society-sponsored workshop with researchers and clinicians with expertise in critical care and symptom management was convened for a discussion of symptom assessment in mechanically ventilated patients. Members included nurses, physicians, a respiratory therapist, a speech-language pathologist, a critical care pharmacist, and a former intensive care unit patient. This report summarizes existing evidence and consensus among workshop participants regarding 1) symptoms that should be considered for routine assessment of adult patients receiving mechanical ventilation; 2) key symptom assessment principles; 3) strategies that support symptom assessment in nonvocal patients; and 4) areas for future clinical practice development and research. Systematic patient-centered assessment of multiple symptoms has great potential to minimize patient distress and improve the patient experience. A culture shift is necessary to promote ongoing holistic symptom assessment with valid and reliable instruments. This report represents our workgroup consensus on symptom assessment for mechanically ventilated patients. Future work should address how holistic, patient-centered symptom assessment can be embedded into clinical practice.

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).

Dyspnea in Patients with Stiff-Person Syndrome

BACKGROUND

Stiff-person syndrome (SPS) is a rare autoimmune disorder that leads to progressively worsening stiffness and spasm of thoracic and proximal-limb musculature. Dyspnea has been reported but not analyzed in patients with SPS.

MATERIALS AND METHODS

For this prospective study, 17 patients were recruited from a university-based neurology clinic. History and exam were performed, demographic information collected and available imaging reviewed. Dyspnea was assessed using vertical visual analog scales (VAS), the University of California San Diego Shortness of Breath Questionnaire (UCSD-SOBQ) and dyspnea "descriptors". Standardized assessments of SPS severity were performed by an experienced neurologist. Forced vital capacity (FVC) spirometric analysis was performed on all patients.

RESULTS

Fifteen of 17 patients complained of dyspnea, including dyspnea at rest, with exertion, and disturbing sleep. A restrictive pattern was the most common abnormality noted on spirometry. FVC (r = -0.67; P < 0.01) and forced expiratory volume in 1-second (FEV1) (r = -0.76; P < 0.01) percent predicted correlated with dyspnea measured by VAS over the preceding 2 weeks. Pulmonary function did not correlate with UCSB-SOBQ or standardized measures of SPS severity.

CONCLUSIONS

Dyspnea in SPS is common and occurs at rest with exertion and disturbs sleep. The finding of restrictive physiology and correlation between pulmonary function variables and dyspnea support the hypothesis that thoracic cage constriction by rigidity and/or spasm of the muscles of the trunk causes or contributes to the sensation of dyspnea. The possibility of diaphragmatic involvement requires further study.

The role of hedonics in the Human Affectome

Experiencing pleasure and displeasure is a fundamental part of life. Hedonics guide behavior, affect decision-making, induce learning, and much more. As the positive and negative valence of feelings, hedonics are core processes that accompany emotion, motivation, and bodily states. Here, the affective neuroscience of pleasure and displeasure that has largely focused on the investigation of reward and pain processing, is reviewed. We describe the neurobiological systems of hedonics and factors that modulate hedonic experiences (e.g., cognition, learning, sensory input). Further, we review maladaptive and adaptive pleasure and displeasure functions in mental disorders and well-being, as well as the experience of aesthetics. As a centerpiece of the Human Affectome Project, language used to express pleasure and displeasure was also analyzed, and showed that most of these analyzed words overlap with expressions of emotions, actions, and bodily states. Our review shows that hedonics are typically investigated as processes that accompany other functions, but the mechanisms of hedonics (as core processes) have not been fully elucidated.

The Impact of Unpredictability on Dyspnea Perception, Anxiety and Interoceptive Error Processing

Dyspnea is a prevalent interoceptive sensation and the aversive cardinal symptom in many cardiorespiratory diseases as well as in mental disorders. Especially the unpredictability of the occurrence of dyspnea episodes has been suggested to be highly anxiety provoking for affected patients. Moreover, previous studies demonstrated that unpredictable exteroceptive stimuli increased self-reports and electrophysiological responses of anxiety such as the startle probe N100 as well as amplified the processing of errors as reflected by greater error-related negativity (ERN). However, studies directly examining the role of unpredictability on dyspnea perception, anxiety, and error processing are widely absent. Using high-density electroencephalography, the present study investigated whether unpredictable compared to predictable dyspnea would increase the perception of dyspnea, anxiety and interoceptive error processing. Thirty-two healthy participants performed a respiratory forced choice reaction time task to elicit an interoceptive ERN during two conditions: an unpredictable and a predictable resistive load-induced dyspnea condition. Predictability was manipulated by pairing (predictable condition) or not pairing (unpredictable condition) dyspnea with a startle tone probe. Self-reports of dyspnea and affective state as well as the startle probe N100 and interoceptive ERN were measured. The results demonstrated greater dyspnea unpleasantness in the unpredictable compared to the predictable condition. Post hoc analyses revealed that this was paralleled by greater anxiety, and greater amplitudes for the startle probe N100 and the interoceptive ERN during the unpredictable relative to the predictable condition, but only when the unpredictable condition was experienced in the first experimental block. Furthermore, higher trait-like anxiety sensitivity was associated with higher ratings for dyspnea unpleasantness and experimental state anxiety ratings. The present findings suggest that unpredictability increases the perception of dyspnea unpleasantness. This effect seems related to increased state and trait anxiety and interoceptive error processing, especially when upcoming dyspnea is particularly unpredictable, such as in early experimental phases. Future studies are required to further substantiate these findings in patients suffering from dyspnea.

Mirtazapine for chronic breathlessness? A review of mechanistic insights and therapeutic potential

INTRODUCTION

Chronic breathlessness is a common and distressing symptom of advanced disease with few effective treatments. Central nervous system mechanisms are important in respiratory sensation and control. Consequently, drugs which may modify processing and perception of afferent information in the brain may have a role. Antidepressants have been proposed; however, current evidence is limited. Of potentially suitable antidepressants, mirtazapine is an attractive option given its tolerability profile, low cost, and wide availability, along with additional potential benefits. Areas covered: The paper provides an overview of the physiology of breathlessness, with an emphasis on central mechanisms, particularly the role of fear circuits and the associated neurotransmitters. It provides a potential rationale for how mirtazapine may improve chronic breathlessness and quality of life in patients with advanced disease. The evidence was identified by a literature search performed in PubMed through to October 2018. Expert opinion: Currently, there is insufficient evidence to support the routine use of antidepressants for chronic breathlessness in advanced disease. Mirtazapine is a promising candidate to pursue, with definitive randomized controlled trials required to determine its efficacy and safety in this setting.

Understanding changes in dyspnoea perception in obstructive lung disease after mindfulness training

Introduction

Dyspnoea has been defined as a ‘subjective experience of breathing discomfort that consists of qualitatively distinct sensations that vary in intensity’. However, the majority of available dyspnoea measures treat it as a single entity and rely on quantitative methodology. We propose that qualitative research can enhance our understanding of dyspnoea, in particular, how perception varies so much among patients with similar disease states. In this paper, we focus on how a specific type of inner attention—mindfulness—may alter perceptions of dyspnoea. The aim is to characterise mindfulness attention, which impacts on perceptions of dyspnoea and relate these to the multidimensional model of dyspnoea. We explore how an individual can change their perception and therefore relationship to similar disease states.

Method

22 patients with asthma or chronic obstructive pulmonary disease were recruited from primary and secondary care to an 8-week course in mindfulness-based cognitive therapy (MBCT). 12 patients took part in an in-depth qualitative interview 2 months after completing the MBCT course. Data were recorded, transcribed and then analysed using a framework approach, drawing on components of the multidimensional model of dyspnoea (multidimensional dyspnoea profile, MDP).

Results

We found that MBCT training involves developing three types of mindful attention (broad attention, informative attention and re-directive attention), which impact on perceptions of the sensory dimension of dyspnoea. MBCT appears to target affective and sensory perceptions articulated in the MDP model.

Conclusion

More research is needed into how mindfulness-based interventions may mediate the relationship between affective experience and the sensory perception of dyspnoea symptoms.

A Systematic Review of Relaxation, Meditation, and Guided Imagery Strategies for Symptom Management in Heart Failure

BACKGROUND

Pain, dyspnea, fatigue, and sleep disturbance are prevalent and distressing symptoms in persons with advanced heart failure. Although many lifestyle and self-care interventions have been developed to control heart failure progression, very few studies have explored treatments exclusively for symptom palliation. Cognitive-behavioral strategies may be effective treatment for these symptoms in advanced heart failure.

OBJECTIVE

A systemic review was conducted to describe the effect of cognitive-behavioral strategies on pain, dyspnea, fatigue, and sleep disturbance in patients with heart failure.

METHODS

CINAHL, Medline, and PsychINFO were searched from inception through December 2014. Articles were selected for inclusion if they tested a cognitive-behavioral strategy using a quasi-experimental or experimental design, involved a sample of adults with heart failure, and measured pain, dyspnea, fatigue, sleep disturbance, or symptom-related quality of life. The 2 authors evaluated study quality, abstracted data elements from each study, and synthesized findings.

RESULTS

Thirteen articles describing 9 unique studies met criteria and were included in the review. Five studies tested relaxation strategies, 3 tested meditation strategies, and 1 tested a guided imagery strategy. Of the 9 studies, 7 demonstrated some improvement in symptom outcomes. Relaxation, meditation, guided imagery, or combinations of these strategies resulted in less dyspnea and better sleep compared with attention control or usual care conditions and reduced pain, dyspnea, fatigue, and sleep disturbance within treatment groups (pretreatment to posttreatment). Symptom-related quality of life was improved with meditation compared with attention control and usual care conditions and improved pre- to post-guided imagery.

CONCLUSIONS

Studies exploring cognitive-behavioral symptom management strategies in heart failure vary in quality and report mixed findings but indicate potential beneficial effects of relaxation, meditation, and guided imagery on heart failure-related symptoms. Future research should test cognitive-behavioral strategies in rigorously designed efficacy trials, using samples selected for their symptom experience, and measure pain, dyspnea, fatigue, and sleep disturbance outcomes with targeted symptom measures.

Dyspnea related to reversibly-binding P2Y12 inhibitors: A review of the pathophysiology, clinical presentation and diagnostics

Dyspnea is a common symptom physiologically associated with strenuous exercise and pathologically reflecting well-known diseases and conditions that are predominantly pulmonary, cardiovascular, and weight-related in origin. Dyspnea improves with appropriate measures that enhance physical performance and treatment of the underlying diseases. Dyspnea is less commonly triggered by other causes such as the environment (e.g., ozone), drugs, and others, some of which do not seem to affect bronchopulmonary function as evidenced by normal results of comprehensive pulmonary function testing. In cardiovascular medicine, dyspnea has recently attracted attention because it has been reported that this symptom occurs more frequently with the administration of the new oral reversibly-binding platelet P2Y12 receptor inhibitors ticagrelor [1-6], cangrelor [7-10], and elinogrel [11]. This paper succinctly addresses the current understanding of the pathophysiology, clinical presentation, and diagnostics of dyspnea, associated either with bronchopulmonary function impairment, as triggered mainly by pulmonary and cardiovascular diseases, or without bronchopulmonary function impairment, as induced by endogenous or external compounds such as drugs in order to provide a context for understanding, recognizing and managing P2Y12 inhibitor-induced dyspnea.

High Thrill and adventure seeking is associated with reduced interoceptive sensitivity: evidence for an altered sex-specific homeostatic processing in high sensation seekers

OBJECTIVE

The personality trait of sensation seeking (SS) has been traditionally linked to the construct of exteroception, i.e. sensing of the outside world. Little is known about the relationship between SS and interoception, i.e. sensing originating in the body. Interoceptive sensations have strong affective and motivational components that may influence behaviors such as risk-taking in SS. This investigation examined whether interoceptive differences contribute to different behavioral characteristics in SS.

METHOD

Using an inspiratory resistive load breathing task, the response to an aversive interoceptive stimulus as a basic homeostatic process was studied in 112 subjects (n=74 females, 38 males). A linear-mixed model approach was used to examine the influence of thrill and adventure seeking (TAS) on the interoceptive response across three levels of breathing resistances (10, 20, 40 cmH₂O/L/sec).

RESULTS

High relative to low TAS individuals were less responsive in evaluating intensities of perceived choking with increasing inspiratory resistive loads. This effect was driven by male, but not female high TAS individuals and was particularly associated with reduced interoceptive sensitivity in males.

CONCLUSION

The conceptualization of SS as primarily driven by exteroceptive stimuli can be expanded to a view of an altered homeostasis in SS, specifically in males.

Evidence for multiple sensory circuits in the brain arising from the respiratory system: an anterograde viral tract tracing study in rodents

Complex sensations accompany the activation of sensory neurons within the respiratory system, yet little is known about the organization of sensory pathways in the brain that mediate these sensations. In the present study, we employ anterograde viral neuroanatomical tract tracing with isogenic self-reporting recombinants of HSV-1 strain H129 to map the higher brain regions in receipt of vagal sensory neurons arising from the trachea versus the lungs, and single-cell PCR to characterize the phenotype of sensory neurons arising from these two divisions of the respiratory tree. The results suggest that the upper and lower airways are predominantly innervated by sensory neurons derived from the somatic jugular and visceral nodose cranial ganglia, respectively. This coincides with central circuitry that is predominately somatic-like, arising from the trachea, and visceral-like, arising from the lungs. Although some convergence of sensory pathways was noted in preautonomic cell groups, this was notably absent in thalamic and cortical regions. These data support the notion that distinct afferent subtypes, via distinct central circuits, subserve sensations arising from the upper versus lower airways. The findings may explain why sensations arising from different levels of the respiratory tree are qualitatively and quantitatively unique.

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.

The breathing conundrum-interoceptive sensitivity and anxiety

Cognitive and affective processing has been the central focus of brain-related functions in psychology and psychiatry for many years. Much less attention has been paid to what could be considered the primary function of the brain, to regulate the function of the body. Recent developments, which include the conceptualization of interoception as a process consisting of integrating the information coming from the inside of the body in the central nervous system and the appreciation that complex emotional processes are fundamentally affected by the processing and regulation of somatic states, have profoundly changed the view of the function and dysfunction of the brain. This review focuses on the relationship between breathing and anxiety. Several anxiety disorders have been associated with altered breathing, perception of breathing, and response to manipulations of breathing. Both clinical and experimental research studies are reviewed that relate breathing dysfunctions to anxiety. Altered breathing may be useful as a physiological marker of anxiety as well as a treatment target using interoceptive interventions.

Psychosocial factors and behavioral medicine interventions in asthma

OBJECTIVE

This review examines the evidence for psychosocial influences in asthma and behavioral medicine approaches to its treatment.

METHOD

We conducted a systematic review of the literature on psychosocial influences and the evidence for behavioral interventions in asthma with a focus on research in the past 10 years and clinical trials. Additional attention was directed at promising new developments in the field.

RESULTS

Psychosocial factors can influence the pathogenesis and pathophysiology of asthma, either directly through autonomic, endocrine, immunological, and central nervous system mechanisms or indirectly through lifestyle factors, health behaviors, illness cognitions, and disease management, including medication adherence and trigger avoidance. The recent decade has witnessed surging interest in behavioral interventions that target the various pathways of influence. Among these, self-management training, breathing training, and exercise or physical activation programs have proved particularly useful, whereas other essential or promising interventions, such as smoking cessation, dietary programs, perception and biofeedback training, and suggestive or expressive psychotherapy, require further, more rigorous evaluation. Given the high comorbidity with anxiety and mood disorders, further evaluation of illness-specific cognitive behavior therapy is of particular importance. Progress has also been made in devising community-based and culturally tailored intervention programs.

CONCLUSION

In concert with an essential medication treatment, behavioral medicine treatment of asthma is moving closer toward an integrated biopsychosocial approach to disease management.

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.

The effects of altered intrathoracic pressure on resting cerebral blood flow and its response to visual stimulation

Investigating how intrathoracic pressure changes affect cerebral blood flow (CBF) is important for a clear interpretation of neuroimaging data in patients with abnormal respiratory physiology, intensive care patients receiving mechanical ventilation and in research paradigms that manipulate intrathoracic pressure. Here, we investigated the effect of experimentally increased and decreased intrathoracic pressures upon CBF and the stimulus-evoked CBF response to visual stimulation. Twenty healthy volunteers received intermittent inspiratory and expiratory loads (plus or minus 9cmH2O for 270s) and viewed an intermittent 2Hz flashing checkerboard, while maintaining stable end-tidal CO2. CBF was recorded with transcranial Doppler sonography (TCD) and whole-brain pseudo-continuous arterial spin labeling magnetic resonance imaging (PCASL MRI). Application of inspiratory loading (negative intrathoracic pressure) showed an increase in TCD-measured CBF of 4% and a PCASL-measured increase in grey matter CBF of 5%, but did not alter mean arterial pressure (MAP). Expiratory loading (positive intrathoracic pressure) did not alter CBF, while MAP increased by 3%. Neither loading condition altered the perfusion response to visual stimulation in the primary visual cortex. In both loading conditions localized CBF increases were observed in the somatosensory and motor cortices, and in the cerebellum. Altered intrathoracic pressures, whether induced experimentally, therapeutically or through a disease process, have possible significant effects on CBF and should be considered as a potential systematic confound in the interpretation of perfusion-based neuroimaging data.

Subjecting elite athletes to inspiratory breathing load reveals behavioral and neural signatures of optimal performers in extreme environments

Background

It is unclear whether and how elite athletes process physiological or psychological challenges differently than healthy comparison subjects. In general, individuals optimize exercise level as it relates to differences between expected and experienced exertion, which can be conceptualized as a body prediction error. The process of computing a body prediction error involves the insular cortex, which is important for interoception, i.e. the sense of the physiological condition of the body. Thus, optimal performance may be related to efficient minimization of the body prediction error. We examined the hypothesis that elite athletes, compared to control subjects, show attenuated insular cortex activation during an aversive interoceptive challenge.

Methodology/Principal Findings

Elite adventure racers (n = 10) and healthy volunteers (n = 11) performed a continuous performance task with varying degrees of a non-hypercapnic breathing load while undergoing functional magnetic resonance imaging. The results indicate that (1) non-hypercapnic inspiratory breathing load is an aversive experience associated with a profound activation of a distributed set of brain areas including bilateral insula, dorsolateral prefrontal cortex and anterior cingulated; (2) adventure racers relative to comparison subjects show greater accuracy on the continuous performance task during the aversive interoceptive condition; and (3) adventure racers show an attenuated right insula cortex response during and following the aversive interoceptive condition of non-hypercapnic inspiratory breathing load.

Conclusions/Significance

These findings support the hypothesis that elite athletes during an aversive interoceptive condition show better performance and an attenuated insular cortex activation during the aversive experience. Interestingly, differential modulation of the right insular cortex has been found previously in elite military personnel and appears to be emerging as an important brain system for optimal performance in extreme environments.

A multidimensional computer adaptive test approach to dyspnea assessment

OBJECTIVES

To develop and test a prototype dyspnea computer adaptive test (CAT).

DESIGN

Prospective study.

SETTING

Two outpatient medical facilities.

PARTICIPANTS

A convenience sample of adults (N=292) with chronic obstructive pulmonary disease (COPD).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURE

We developed a modified and expanded item bank and CAT for the Dyspnea Management Questionnaire (DMQ), an outcome measure consisting of 4 dyspnea dimensions: dyspnea intensity, dyspnea anxiety, activity avoidance, and activity self-efficacy.

RESULTS

Factor analyses supported a 4-dimensional model underlying the 71 DMQ items. The DMQ item bank achieved acceptable Rasch model fit statistics, good measurement breadth with minimal floor and ceiling effects, and evidence of high internal consistency reliability (α=.92-.98). With the use of CAT simulation analyses, the DMQ-CAT showed high measurement accuracy compared with the total item pool (r=.83-.97, P<.0001) and evidence of good to excellent concurrent validity (r=-.61 to -.80, P<.0001). All DMQ-CAT domains showed evidence for known-groups validity (P≤.001).

CONCLUSIONS

The DMQ-CAT reliably and validly captured 4 distinct dyspnea domains. Multidimensional dyspnea assessment in COPD is needed to better measure the effectiveness of pharmacologic, pulmonary rehabilitation, and psychosocial interventions in not only alleviating the somatic sensation of dyspnea but also reducing dysfunctional emotions, cognitions, and behaviors associated with dyspnea, especially for anxious patients.

Panic attacks and panic disorder in chronic obstructive pulmonary disease: a cognitive behavioral perspective

The prevalence of panic disorder in patients with chronic obstructive pulmonary disease (COPD) is up to 10 times greater than the overall population prevalence of 1.5-3.5%, and panic attacks are commonly experienced. When present, clinically significant anxiety decreases quality of life for COPD patients, and also increases health care costs. Therefore, understanding why COPD patients have such high rates of panic attacks and panic disorder is important for optimal management of COPD. The cognitive model of panic anxiety is the most widely accepted theory of panic attacks and panic disorder in physically healthy adults. According to this model, panic attacks occur when catastrophic misinterpretations of ambiguous physical sensations (such as shortness of breath or increased heart rate) increase arousal, creating a positive feedback loop that results in panic. As the major symptom of a terminal illness that threatens our most basic physical requirement, dyspnea in COPD is open to catastrophic misinterpretation. There is some experimental and clinical evidence for the applicability of the cognitive model of panic anxiety in COPD, and of the utility of cognitive behavior therapy (CBT), based on this model, for treating anxiety symptoms and panic attacks in COPD patients. However, there is much need for further studies. Evidence is increasing that mental health professionals, in collaboration with multi-disciplinary pulmonary teams, potentially have key roles to play in preventing and treating panic attacks and panic disorder in COPD patients. This review addresses diagnosis, epidemiology, theoretical conceptualizations, treatment, and recommendations for future research.

Efficacy of guided imagery with theta music for advanced cancer patients with dyspnea: a pilot study

BACKGROUND

Dyspnea is a frequent and devastating symptom among advanced cancer patients for which improved and low-cost palliative techniques are needed.

METHODS

A one-group repeated measures research design investigated the efficacy of guided imagery (GI) with theta music (M) on dyspnea in advanced cancer patients. The intervention consisted of four periods: (a) pretest; (b) intervention with peaceful non-M; (c) intervention with 10 min of GI with M (GI/M), with the first and last 3 min being M only (i.e., the middle 4 min was GI/M); and (d) posttest. Dyspnea outcome was measured with the Modified Borg Scale (MBS) for self-reported evaluation of dyspneic symptoms. Physiological parameters measured were pulse oxygen saturation (SpO(2)), end-tidal CO( 2) (EtCO(2)), heart rate (HR), and respiratory rate (RR). Posttest qualitative data were obtained via interview for subjective patient experience.

RESULTS

Participants included 53 patients, 33% with lung cancer. GI/M produced a significant decrease in MBS scores; 90% of the subjects gave positive qualitative reviews of GI/M. SpO(2) did not change significantly over time. GI/M significantly increased EtCO(2), decreased RR, and decreased HR.

DISCUSSION

This study demonstrates that GI/M is a useful intervention for palliative care of patients with dyspnea. M alone was demonstrated to be effective, while soothing non-M was not effective. GI/M was more effective than M alone. GI/M should be considered low-cost end-of-life palliative care for dyspnea.

Additional evidence for the affective dimension of dyspnea in patients with COPD

The primary purpose of this secondary analysis was to determine whether 103 participants with chronic obstructive pulmonary disease rated the affective dimension of dyspnea (dyspnea-related anxiety and dyspnea-related distress) separately from the sensory dimension (intensity) during baseline exercise testing conducted as part of a randomized clinical trial. A secondary purpose was to determine if dyspnea-related anxiety and distress were rated distinctly different from other measurements of anxiety. At the end of a 6-minute walk and an incremental treadmill test, participant ratings of the magnitude of dyspnea-related anxiety and distress on the Modified Borg Scale were significantly different from their ratings of the intensity of dyspnea. Dyspnea-related anxiety and distress also appeared to be concepts independent from measures of state anxiety, negative affect, and anxiety before a treadmill test.

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.

Repeated breathlessness experiences induced by hypercapnia: differential effects on intensity and unpleasantness

BACKGROUND

The present study investigated the effect of repeated hypercapnic challenges on the sensory (intensity [I]) and affective (unpleasantness [U]) dimensions of breathlessness.

METHODS

Three subsequent rebreathing trials (Read, 1968) were administered to healthy men and women (n = 39). The I and U of breathlessness were rated every 20 s during the baseline, rebreathing, and recovery phases. Breathing behavior (fractional end-tidal CO(2) [Fetco(2)] and minute ventilation [Ve]) was monitored continuously. Intraindividual linear regression slopes for Fetco(2) and Ve] were calculated and standardized, separately for both rating dimensions.

RESULTS

Both the absolute magnitude and the slope of the I of breathlessness were higher compared to U (p < 0.05). Across-trial habituation of the peak I and U of breathlessness occurred in both genders (p < 0.001), but habituation was larger for the U than for the I (p = 0.05).

CONCLUSIONS

The findings show that the sensory and affective dimensions of breathlessness can meaningfully be distinguished during hypercapnic challenges and that repeated exposures have different effects on both dimensions.

Mechanisms of dyspnea in chronic lung disease

PURPOSE OF REVIEW

To discuss three emerging areas of research triggering new hypotheses for mechanisms of dyspnea.

RECENT FINDINGS

There has been an emphasis on the importance of lung volumes in evaluating symptoms and lung function in patients with chronic obstructive pulmonary disease. Dyspnea intensity seems to more closely correlate with measures of hyperinflation than airflow limitation, highlighting the importance of neuromechanical dissociation in the development of dyspnea. Inhaled furosemide has demonstrated a beneficial effect in laboratory-induced dyspnea, and the sensation of air hunger has been ameliorated by this therapy, possibly via activation of pulmonary stretch receptors. There appear to be distinct affective and sensory components of dyspnea, and the affective dimension may be modifiable, although this has not been fully studied.

SUMMARY

Dyspnea in chronic obstructive pulmonary disease is clearly related to hyperinflation, and lung volumes are valuable for characterizing disease. It remains unclear whether a limitation in tidal volume due to dynamic hyperinflation is the key factor in exertional dyspnea in this disease. Research of inhaled furosemide demonstrates the importance of afferent sensory input in modifying dyspnea, and deserves further study. The contributions of the affective and sensory components of dyspnea remain unclear, but should be studied further.

The multiple dimensions of dyspnea: review and hypotheses

Although dyspnea is a common and troubling symptom, our understanding of the neurophysiology of dyspnea is woefully incomplete. Most measurements of dyspnea treat it as a single entity. Although the multidimensional dyspnea concept has been mentioned for many decades, only recently has the concept been the subject of experimental tests. Emerging evidence has begun to favor the hypothesis that dyspnea comprises multiple dimensions or components that can be measured as different entities. Most recently, studies have begun to show that there is a separable 'affective dimension' (i.e. unpleasantness and emotional impact). Understanding of the multidimensional measurement of pain is far in advance of dyspnea, and has enabled progress in the neurophysiology of pain, including identification of separate neural structures subserving various elements of pain perception. We propose here a multidimensional model of dyspnea based on a state-of-the-art pain model, and review existing evidence in the light of this model.

The language of breathlessness differentiates between patients with COPD and age-matched adults

BACKGROUND

If descriptors of the sensation of breathlessness are able to differentiate between medical conditions, the language of breathlessness could potentially have a role in differential diagnosis. This study investigated whether the language used to describe the sensation of breathlessness accurately categorized older individuals with and without a prior diagnosis of COPD.

METHODS

Using a parallel-group design, participants with and without a prior diagnosis of COPD volunteered words and phrases and endorsed up to three statements to describe their sensation of breathlessness. Cluster analysis (v-fold cross-validation) was applied, and subjects were clustered by their choice of words. Cluster membership was then compared to original group membership (COPD vs non-COPD), and predictive power was assessed.

RESULTS

Groups were similar for age and gender (COPD, n = 94; 48 men; mean age, 70 +/- 10 years [+/- SD]; vs non-COPD, n = 55; 21 men; mean age, 69 +/- 13 years) but differed significantly in breathlessness-related impairment, intensity, and quality of life (p < 0.0001). Cluster membership corresponded accurately with original group classifications (volunteered, 85%; and up to three statements, 68% agreement). Classification based on a single best descriptor (volunteered [62%] or endorsed [55%]) was less accurate for group membership.

CONCLUSIONS

Language used to describe the sensation of breathlessness differentiated people with and without a prior diagnosis of COPD when descriptors were not limited to a single best word or statement.

The etiology and management of intractable breathlessness in patients with advanced cancer: a systematic review of pharmacological therapy

Intractable breathlessness is a common, devastating symptom of advanced cancer causing distress and isolation for patients and families. In advanced cancer, breathlessness is complex and usually multifactorial and its severity unrelated to measurable pulmonary function or disease status. Therapeutic advances in the clinical management of dyspnea are limited and it remains difficult to treat successfully. There is growing interest in the palliation of breathlessness, and recent work has shown that a systematic, evidence-based approach by a committed multidisciplinary team can improve lives considerably. Where such care is lacking it may be owing to therapeutic nihilism in clinicians untrained in the management of chronic breathlessness and unaware that there are options other than endurance. Optimum management involves pharmacological treatment (principally opioids, occasionally oxygen and anxiolytics) and nonpharmacological interventions (including use of a fan, a tailor-made exercise program, and psychoeducational support for patient and family) with the use of parenteral opioids and sedation at the end of life when appropriate. Effective care centers on the patient's needs and goals. Priorities in breathlessness research include studies on: neuroimaging, the effectiveness of new interventions, the efficacy, safety, and dosing regimens of opioids, the contribution of deconditioning, and the effect of preventing or reversing breathlessness.

The affective dimension of laboratory dyspnea: air hunger is more unpleasant than work/effort

RATIONALE

It is hypothesized that the affective dimension of dyspnea (unpleasantness, emotional response) is not strictly dependent on the intensity of dyspnea.

OBJECTIVES

We tested the hypothesis that the ratio of immediate unpleasantness (A(1)) to sensory intensity (SI) varies depending on the type of dyspnea.

METHODS

Twelve healthy subjects experienced three stimuli: stimulus 1: maximal eucapnic voluntary hyperpnea against inspiratory resistance, requiring 15 times the work of resting breathing; stimulus 2: Pet(CO(2)) 6.1 mm Hg above resting with ventilation restricted to less than spontaneous breathing; stimulus 3: Pet(CO(2)) 7.7 mm Hg above resting with ventilation further restricted. After each trial, subjects rated SI, A(1), and qualities of dyspnea on the Multidimensional Dyspnea Profile (MDP), a comprehensive instrument tested here for the first time.

MEASUREMENTS AND MAIN RESULTS

Stimulus 1 was always limited by subjects failing to meet a higher ventilation target; none signaled severe discomfort. This evoked work and effort sensations, with relatively low unpleasantness (mean A(1)/SI = 0.64). Stimulus 2, titrated to produce dyspnea ratings similar to those subjects gave during stimulus 1, evoked air hunger and produced significantly greater unpleasantness (mean A(1)/SI = 0.95). Stimulus 3, increased until air hunger was intolerable, evoked the highest intensity and unpleasantness ratings and high unpleasantness ratio (mean A(1)/SI = 1.09). When asked which they would prefer to repeat, all subjects chose stimulus 1.

CONCLUSIONS

(1) Maximal respiratory work is less unpleasant than moderately intense air hunger in this brief test; (2) unpleasantness of dyspnea can vary independently from perceived intensity, consistent with the prevailing model of pain; (3) separate dimensions of dyspnea can be measured with the MDP.

Distractive Auditory Stimuli Reduce the Unpleasantness of Dyspnea During Exercise in Patients With COPD

BACKGROUND

Dyspnea is the primary symptom limiting exercise in patients with COPD. Recent research has demonstrated that psychological factors can substantially influence the perception of dyspnea, but little is known about the modulation of perceived intensity or unpleasantness of dyspnea by attentional distraction. Therefore, we examined the impact of distractive auditory stimuli on the perception of exercise-induced dyspnea and the affective state in patients with COPD during 6-min walking tests (6MWTs).

METHODS

Twenty patients with mild-to-severe COPD (mean FEV1, 55.9% predicted) underwent two 6MWTs. Under one exercise condition, distractive auditory stimuli were presented with headphones, while the other condition was performed without auditory distraction. Lung function (FEV1), heart rate (HR), pulse oximetric saturation (SpO2), perceived intensity of dyspnea (ie, visual analog scale for perceived intensity of dyspnea [VAS-I]), and perceived unpleasantness of dyspnea (visual analog scale for perceived unpleasantness of dyspnea [VAS-U]) were measured before and after exercise. In addition, the global level of dyspnea (Borg score), positive affectivity (PA), and negative affectivity were assessed after both conditions.

RESULTS

A similar exercise level during both conditions was confirmed by comparable results in FEV1, HR, SpO2, and distances walked. During auditory distraction, Borg scores and increases in VAS-U were smaller, while PA was higher compared to the nondistraction condition (p<0.05). VAS-I did not show differences across conditions.

CONCLUSIONS

Distractive auditory stimuli decrease the global level of exercise-induced dyspnea in patients with COPD by reducing the perceived unpleasantness of dyspnea and lead to an additional increase in PA. Auditory distraction might therefore serve as an intervention for the reduction of dyspnea during exercise in this patient group.

The influence of corticosteroids on the perception of dyspnea in asthma

Corticosteroids are effective anti-inflammatory medications that are recommended for the control of persistent asthma. Little, however, is known about their influence on the perception of dyspnea, which, in turn, is important to the successful self-management of asthma. This paper provides a synopsis of available studies examining the impact of corticosteroids on the sensitivity to perceive dyspnea and presents possible mechanisms underlying this relationship. The results of these investigations are conflicting with some studies showing improved perception and other studies showing worsened perception of dyspnea after corticosteroid treatment. Thus, firm conclusions cannot be derived from the currently available data. Implications for future research, which is required to increase our understanding of potential influences of corticosteroids on the perception of dyspnea, are provided.