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

Comparing recalled versus experienced symptoms of breathlessness ratings: An ecological assessment study using mobile phone technology

BACKGROUND AND OBJECTIVE

Recall of breathlessness is important for clinical care but might differ from the experienced (momentary) symptoms. This study aimed to characterize the relationship between momentary breathlessness ratings and the recall of the experience. It is hypothesized that recall is influenced by the peak (worst) and end (most recent) ratings of momentary breathlessness (peak-end rule).

METHODS

This study used mobile ecological momentary assessment (mEMA) for assessing breathlessness in daily life through an application installed on participants' mobile phones. Breathlessness ratings (0-10 numerical rating scale) were recorded throughout the day and recalled each night and at the end of the week. Analyses were performed using regular and mixed linear regression.

RESULTS

Eighty-four people participated. Their mean age was 64.4 years, 60% were female and 98% had modified Medical Research Council (mMRC) ≥ 1. The mean number of momentary ratings of breathlessness provided was 7.7 ratings/participant/day. Recalled breathlessness was associated with the mean, peak and end values of the day. The mean was most closely associated with the daily recall. Associations were strong for weekly values: peak breathlessness (beta = 0.95, r2  = 0.57); mean (beta = 0.91, r2  = 0.53); and end (beta = 0.67, r2  = 0.48); p < 0.001 for all. Multivariate analysis showed that peak breathlessness had the strongest influence on the breathlessness recalled at the end of the week.

CONCLUSION

Over 1 week, recalled breathlessness is most strongly influenced by the peak breathlessness; over 1 day, it is mean breathlessness that participants most readily recalled.

Mechanisms underlying the sensation of dyspnea

Dyspnea is defined as a subjective experience of breathing discomfort that consists of qualitatively distinct sensations that vary in intensity. It is a common symptom among patients with respiratory diseases that reduces daily activities, induces deconditioning, and is self-perpetuating. Although clinical interventions are needed to reduce dyspnea, its underlying mechanism is poorly understood depending on the intertwined peripheral and central neural mechanisms as well as emotional factors. Nonetheless, experimental and clinical observations suggest that dyspnea results from dissociation or a mismatch between the intended respiratory motor output set caused by the respiratory neuronal network in the lower brainstem and the ventilatory output accomplished. The brain regions responsible for detecting the mismatch between the two are not established. The mechanism underlying the transmission of neural signals for dyspnea to higher sensory brain centers is not known. Further, information from central and peripheral chemoreceptors that control the milieu of body fluids is summated at higher brain centers, which modify dyspneic sensations. The mental status also affects the sensitivity to and the threshold of dyspnea perception. The currently used methods for relieving dyspnea are not necessarily fully effective. The search for more effective therapy requires further insights into the pathophysiology of dyspnea.

Breathlessness and the brain: the role of expectation

PURPOSE OF REVIEW

Breathlessness debilitates countless people with a wide range of common diseases. For some people, the experience of breathlessness is poorly explained by the findings of medical tests. This disparity complicates diagnostic and treatment options and means that disease-modifying treatments do not always have the expected effect upon symptoms. These observations suggest that brain processing of respiratory perceptions may be somewhat independent of disease processes. This may help to explain the dissonance observed in some patients between physical disease markers and the lived experience of breathlessness.

RECENT FINDINGS

A body of breathlessness research using functional neuroimaging has identified a relatively consistent set of brain areas that are associated with breathlessness. These areas include the insula, cingulate and sensory cortices, the amygdala and the periaqueductal gray matter. We interpret these findings in the context of new theories of perception that emphasize the importance of distributed brain networks. Within this framework, these perceptual networks function by checking an internal model (a set of expectations) against peripheral sensory inputs, instead of the brain acting as a passive signal transducer. Furthermore, other factors beyond the physiology of breathlessness can influence the system.

SUMMARY

A person's expectations and mood are major contributors to the function of the brain networks that generate perceptions of breathlessness. Breathlessness, therefore, arises from inferences made by the brain's integration of both expectations and sensory inputs. By better understanding individual differences across these contributing perceptual factors, we will be better poised to develop targeted and individualized treatments for breathlessness that could complement disease-modifying therapies.

Differences between experienced and recalled breathlessness: a review

PURPOSE OF REVIEW

Experienced breathlessness and recalled breathlessness are two different entities, which may be associated with different factors and might have different impacts on function for the individual. The aim was to review the knowledge from the last 2 years concerning experienced breathlessness and recalled breathlessness and related factors.

RECENT FINDINGS

Experienced breathlessness was most often induced or measured during exercise testing in a lab environment using a modified Borg scale. It was associated with both psychological factors, such as social rejection, presence of others, psychosocial stress and prenatal exposure to stress, as well as physical factors, such as hypoxia and frequent exacerbations.Recalled breathlessness was most often measured in epidemiological studies, most commonly using the modified Medical Research Council scale. It was associated with lung volumes, overweight, exercise training, frailty, smoking, personality traits, behavior and marital and occupational status.

SUMMARY

No studies during the review period had directly compared experienced breathlessness and recalled breathlessness. Several factors were related to either experienced breathlessness or recalled breathlessness but no clear differences between factors were found in this review. There is a need for comparative studies using the same measurement methods and in the same settings in order to examine their relation.

Relating Experienced To Recalled breathlessness Observational (RETRO) study: a prospective study using a mobile phone application

Background

Breathlessness, the subjective sensation of breathing discomfort, is common and appears in the daily life of people with cardiorespiratory diseases. Physicians often rely on patient's history based on symptom recall. The relation between recalled and experienced breathlessness is still poorly understood. This paper presents the protocol for a study primarily aimed at evaluating the relationship between experienced breathlessness and (1) recalled breathlessness and (2) predicted future breathlessness.

Methods

A mobile phone application will be used to collect data during daily life. Medically stable participants, ≥18 years of age with mean daily breathlessness of Numerical Rating Scale (NRS) 3/10 and able to use a mobile phone with internet will rate their breathlessness intensity on a 0-10 NRS prompted the user several times daily for 1 week. Participants will recall their breathlessness each day and week. Multivariable random effects regression models will be used for statistical analyses.

Results

Results of the study will be submitted for publication in peer-reviewed journals and presented at relevant conferences.

Discussion

This protocol describes a study aimed at investigating previously unknown areas of the experience and recall of breathlessness using a new method of data collection.

Registration details

Prospectively registered with ClinicalTrials.gov (Nr: NCT03468205).

Ethics and dissemination

The study has received ethical approval from the Regional Ethical Review Board Lund (DNr 2017/149). After a general study information including that participation is entirely voluntary, participants will answer the eligibility criteria and be asked to consent to participate before entering the study questions. Written informed consent to participate will be obtained for participants in the clinical sub-cohort. Participation can be discontinued at the discretion of the participant in which case no further data will be collected.

Comparison of the Dyspnoea-12 and Multidimensional Dyspnoea Profile in people with COPD

We directly compared convergent, discriminant and concurrent validity of the Dyspnoea-12 (D-12) and Multidimensional Dyspnoea Profile (MDP) in people with chronic obstructive pulmonary disease.

Breathlessness measures (D-12, MDP, visual analogue scales and descriptors) were completed for two focal periods (daily life and end of walk test). Instrument structure (D-12 and MDP item grouping) was assessed with factor analysis. Differences between airflow severity stage and focal periods (ANOVA, t-test and Chi-squared test), associations between D-12 and MDP (r, r2 for static pulmonary function, 6-min walk test and self-reported measures of impairment) and individual consistency for comparable items of the D-12 and MDP (McNemar's test) were assessed.

In 84 participants (mean±sd age 70±9 years, 47 males, forced expiratory volume in 1 s 48±17% predicted), item groupings were confirmed for both focal periods. Developer-recommended single and subdomain scores were highly correlated, and demonstrated similar convergent, discriminant and concurrent validity. Individual consistency differed between the D-12 and MDP according to item/item groups.

At the level of developer-recommended single and subdomain scores, the D-12 and MDP share similar psychometric properties, but these instruments serve different purposes, do not assess the same sensations or emotions and are not interchangeable.

Test-retest reliability of multidimensional dyspnea profile recall ratings in the emergency department: a prospective, longitudinal study

BACKGROUND

Dyspnea is among the most common reasons for emergency department (ED) visits by patients with cardiopulmonary disease who are commonly asked to recall the symptoms that prompted them to come to the ED. The reliability of recalled dyspnea has not been systematically investigated in ED patients.

METHODS

Patients with chronic or acute cardiopulmonary conditions who came to the ED with dyspnea (N = 154) completed the Multidimensional Dyspnea Profile (MDP) several times during the visit and in a follow-up visit 4 to 6 weeks later (n = 68). The MDP has 12 items with numerical ratings of intensity, unpleasantness, sensory qualities, and emotions associated with how breathing felt when participants decided to come to the ED (recall MDP) or at the time of administration ("now" MDP). The recall MDP was administered twice in the ED and once during the follow-up visit. Principal components analysis (PCA) with varimax rotation was used to assess domain structure of the recall MDP. Internal consistency reliability was assessed with Cronbach's alpha. Test-retest reliability was assessed with intraclass correlation coefficients (ICCs) for absolute agreement for individual items and domains.

RESULTS

PCA of the recall MDP was consistent with two domains (Immediate Perception, 7 items, Cronbach's alpha = .89 to .94; Emotional Response, 5 items; Cronbach's alpha = .81 to .85). Test-retest ICCs for the recall MDP during the ED visit ranged from .70 to .87 for individual items and were .93 and .94 for the Immediate Perception and Emotional Response domains. ICCs were much lower for the interval between the ED visit and follow-up, both for individual items (.28 to .66) and for the Immediate Perception and Emotional Response domains (.72 and .78, respectively).

CONCLUSIONS

During an ED visit, recall MDP ratings of dyspnea at the time participants decided to seek care in the ED are reliable and sufficiently stable, both for individual items and the two domains, that a time lag between arrival and questionnaire administration does not critically affect recall of perceptual and emotional characteristics immediately prior to the visit. However, test-retest reliability of recall over a 4- to 6-week interval is poor for individual items and significantly attenuated for the two domains.

An official American Thoracic Society statement: update on the mechanisms, assessment, and management of dyspnea

BACKGROUND

Dyspnea is a common, distressing symptom of cardiopulmonary and neuromuscular diseases. Since the ATS published a consensus statement on dyspnea in 1999, there has been enormous growth in knowledge about the neurophysiology of dyspnea and increasing interest in dyspnea as a patient-reported outcome.

PURPOSE

The purpose of this document is to update the 1999 ATS Consensus Statement on dyspnea.

METHODS

An interdisciplinary committee of experts representing ATS assemblies on Nursing, Clinical Problems, Sleep and Respiratory Neurobiology, Pulmonary Rehabilitation, and Behavioral Science determined the overall scope of this update through group consensus. Focused literature reviews in key topic areas were conducted by committee members with relevant expertise. The final content of this statement was agreed upon by all members.

RESULTS

Progress has been made in clarifying mechanisms underlying several qualitatively and mechanistically distinct breathing sensations. Brain imaging studies have consistently shown dyspnea stimuli to be correlated with activation of cortico-limbic areas involved with interoception and nociception. Endogenous and exogenous opioids may modulate perception of dyspnea. Instruments for measuring dyspnea are often poorly characterized; a framework is proposed for more consistent identification of measurement domains.

CONCLUSIONS

Progress in treatment of dyspnea has not matched progress in elucidating underlying mechanisms. There is a critical need for interdisciplinary translational research to connect dyspnea mechanisms with clinical treatment and to validate dyspnea measures as patient-reported outcomes for clinical trials.

An official American Thoracic Society statement: update on the mechanisms, assessment, and management of dyspnea

BACKGROUND

Dyspnea is a common, distressing symptom of cardiopulmonary and neuromuscular diseases. Since the ATS published a consensus statement on dyspnea in 1999, there has been enormous growth in knowledge about the neurophysiology of dyspnea and increasing interest in dyspnea as a patient-reported outcome.

PURPOSE

The purpose of this document is to update the 1999 ATS Consensus Statement on dyspnea.

METHODS

An interdisciplinary committee of experts representing ATS assemblies on Nursing, Clinical Problems, Sleep and Respiratory Neurobiology, Pulmonary Rehabilitation, and Behavioral Science determined the overall scope of this update through group consensus. Focused literature reviews in key topic areas were conducted by committee members with relevant expertise. The final content of this statement was agreed upon by all members.

RESULTS

Progress has been made in clarifying mechanisms underlying several qualitatively and mechanistically distinct breathing sensations. Brain imaging studies have consistently shown dyspnea stimuli to be correlated with activation of cortico-limbic areas involved with interoception and nociception. Endogenous and exogenous opioids may modulate perception of dyspnea. Instruments for measuring dyspnea are often poorly characterized; a framework is proposed for more consistent identification of measurement domains.

CONCLUSIONS

Progress in treatment of dyspnea has not matched progress in elucidating underlying mechanisms. There is a critical need for interdisciplinary translational research to connect dyspnea mechanisms with clinical treatment and to validate dyspnea measures as patient-reported outcomes for clinical trials.