Peak-end memory bias in laboratory-induced dyspnea: a comparison of patients with medically unexplained symptoms and healthy controls

Adding a nonpainful end to reduce pain recollection of Pap smear screening: a randomized controlled trial

ABSTRACT

The pain experienced during Pap tests is a crucial gap in reducing cervical cancer burden. This study sought to investigate whether adding a nonpainful step at the end of Pap tests helps women recall less pain. We conducted a randomized controlled trial on women aged 30 to 70 years at a cervical cancer screening center. A nonpainful step was added at the end of Pap test in the modified Pap group. The outcomes included recalled pain after Pap smear screening, real-time pain, and 1-year willingness to receive further Pap tests. Among 266 subjects in the intention-to-treat analysis, the modified Pap group (n = 133) experienced lower 5-minute recalled pain than the traditional Pap group on a 1 to 5 numeric scale (mean [SD], 1.50 [0.77] vs 2.02 [1.12]; P < 0.001) and a 0 to 10 visual analog scale (2.12 [1.79] vs 3.12 [2.23]; P < 0.001). In exploratory subgroup analyses, the association between the modified Pap test and reduced 5-minute recalled pain was not affected by predicted pain, demographic, or socioeconomic characteristics, but it was more apparent in postmenopausal women. Consistently, the modified Pap test attenuated 1-year recalled pain on both pain scales. Furthermore, the modified Pap test increased 1-year willingness grade to receive further Pap tests (adjusted β [SE], 2.11 [0.27]; P < 0.001). In conclusion, adding a nonpainful step at the end of Pap smear screening reduces on-site and long-term recalled pain and strengthens willingness to undergo subsequent Pap tests regularly. The modified Pap test contributes to cervical cancer screening participation.

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.

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.

Real-time measurement of post-stroke fatigue in daily life and its relationship with the retrospective Fatigue Severity Scale

Improving our understanding of post-stroke fatigue is crucial to develop more effective interventions. This effort may be hampered by the methods used to assess fatigue, which usually rely on retrospective memory reports. However, such reports are prone to memory bias and may not capture variability in fatigue in daily life; thereby failing to adequately represent symptom experience. This study aimed to assess the strength of the relationship between real-time experience of post-stroke fatigue and the commonly used retrospective Fatigue Severity Scale (FSS). Thirty individuals with stroke completed 10 daily questionnaires about momentary (here-and-now) fatigue for six consecutive days using the mHealth application PsyMate^TM (Experience Sampling Method). From these real-time fatigue ratings (N = 1012), we calculated three indices: total average, peak fatigue, and fatigue on the final day. Afterwards, participants rated their fatigue retrospectively with the FSS. Results showed weak to moderate and strong correlations (range: .334, .667), with retrospective reports capturing up to 44% of the variance in the indices of momentary fatigue. Exploratory analyses also revealed that even individuals with similar total FSS scores demonstrated highly different day-to-day fatigue patterns. We conclude that retrospective measures may provide an incomplete view of post-stroke fatigue and diurnal variation therein.

Ecological momentary assessments (EMAs) did not improve responsiveness of patient-reported outcomes on quality of life

OBJECTIVES

Clinical practice guidelines recommend questionnaires with short recall. We compare responsiveness of ecological momentary assessments (EMAs) and retrospective assessments of thyroid-related quality of life.

STUDY DESIGN AND SETTING

Patients with newly diagnosed thyrotoxicosis completed retrospective Thyroid-related Patient-Reported Outcome measures (ThyPROs) with 4-week and 1-week recall, respectively, and three daily EMAs for 4 weeks at time of inclusion and again after treatment (N = 115). Magnitude of change and statistical power (F-test statistics) were compared. Two designs were applied to the same data: Design 1 mimicked the practical realities of clinical trials by comparing 4-week recall ThyPRO administered at time of inclusion with EMA initiated at time of inclusion and collected prospectively for 1 week, thus not covering the same time frame or duration. Design 2 compared assessments covering the same 4 weeks after inclusion.

RESULTS

Design 1: the estimated change and statistical power were significantly larger for 4-week ThyPRO compared with EMAs. Design 2: retrospective assessments and EMAs had comparable change and power. Repeated 1-week ThyPRO administrations increased the statistical power.

CONCLUSION

Selecting the optimal time frame for evaluation proved crucial for responsiveness. EMAs did not provide higher responsiveness than retrospective measures in either design. Repeated 1-week ThyPRO administrations increased statistical power.

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.

All's Bad That Ends Bad: There Is a Peak-End Memory Bias in Anxiety

The peak-end memory bias has been well documented for the retrospective evaluation of pain. It describes that the retrospective evaluation of pain is largely based on the discomfort experienced at the most intense point (peak) and at the end of the episode. This is notable because it means that longer episodes with a better ending can be remembered as less aversive than shorter ones; this is even if the former had the same peak in painfulness and an overall longer duration of pain. Until now, this bias has not been studied in the domain of anxiety despite the high relevance of variable levels of anxiety in the treatment of anxiety disorders. Therefore, we set out to replicate the original studies but with an induction of variable levels of anxiety. Of 64 women, half watched a clip from a horror movie which ended at the most frightening moment. The other half watched an extended version of this clip with a moderately frightening ending. Afterward, all participants were asked to rate the global anxiety which was elicited by the video. When the film ended at the most frightening moment, participants retrospectively reported more anxiety than participants who watched the extended version. This is the first study to document that the peak-end bias can be found in the domain of anxiety. These findings require replication and extension to a treatment context to evaluate its implications for exposure therapy.

A longitudinal analysis of pain experience and recall in fibromyalgia

AIM

To evaluate pain experiences and memories in fibromyalgia (FM) patients over time.

METHOD

Participants included 572 females who were members of a large health maintenance organization who had a diagnosis of FM syndrome (FMS) and met inclusion criteria for the study. Recruitment was for an intervention study that tested the effects of social support and education treatment arms, but there were no treatment effects. Reports of experiential pain (EP), historical peak pain (HPP), and historical valley pain (HVP) for FM were collected. Differences between HPP and EP and EP and HVP (bias) were calculated to determine whether HPP and HVP were distributed evenly around EP over time across participants. Models were performed to assess personal history and psychosocial factors that affect EP, HPP, HVP, and bias.

RESULTS

There was systematic tendency for HPP to be significantly larger than EP relative to EP vs HVP. EP and HPP decreased significantly over time, but not HVP. There were significant predictors of EP, HPP, HVP, and bias, including depression, self-efficacy, and sleep quality, among others.

CONCLUSION

The experiences and recollections of pain in FM appear to provide a unique means of understanding the maintenance of chronic pain-including factors that affect this process.

Retrospective memory for symptoms in patients with medically unexplained symptoms

OBJECTIVE

Clinical assessment and diagnostic processes heavily rely on memory-based symptom reports. The current study investigated memory for symptoms and the peak-end effect for dyspnea in patients with medically unexplained symptoms and healthy participants.

METHODS

Female patients with medically unexplained dyspnea (MUD) (n=22) and matched healthy controls (n=22) participated in two dyspnea induction trials (short, long). Dyspnea ratings were collected: (1) continuously during symptom induction (concurrent with respiratory measures), (2) immediately after the experiment, and (3) after 2weeks. Symptoms, negative affect, and anxiety were assessed at baseline and after every trial. The mediating role of state anxiety in symptom reporting was assessed. The peak-end effect was tested with forced-choice questions measuring relative preference for the trials.

RESULTS

Compared to controls, dyspnea induction resulted in higher levels of symptoms, anxiety, concurrent dyspnea ratings, and minute ventilation in the patient group. In both groups, immediate retrospective ratings were higher than averaged concurrent ratings. No further increase in dyspnea ratings was observed at 2-week recall. Retrospective dyspnea ratings were mediated by both state anxiety and concurrent dyspnea ratings. Patients did not show a peak-end effect, whereas controls did.

CONCLUSION

The findings show that patients' experience of a dyspneic episode is subject to immediate memory bias, but does not change over a longer time period. The results also highlight the importance of affective state during symptom experience for both symptom perception and memory.

Are within-person Numerical Rating Scale (NRS) ratings of breathlessness 'on average' valid in advanced disease for patients and for patients' informal carers?

INTRODUCTION

The Numerical Rating Scale (NRS) is frequently used to assess patient-reported breathlessness in both a research and clinical context. A subgroup of patients report average breathlessness as worse than their worst breathlessness in the last 24 hours (paradoxical average). The Peak/End rule describes how the most extreme and current breathlessness influence reported average. This study seeks to highlight the existence of a subpopulation who give 'paradoxical averages using the NRS, to characterise this group and to investigate the explanatory relevance of the 'Peak/End' rule.

METHODS

Data were collected within mixed method face-to-face interviews for three studies: the Living with Breathlessness Study and the two subprotocols of the Breathlessness Intervention Service phase III randomised controlled trial. Key variables from the three datasets were pooled (n=561), and cases where participants reported a paradoxical average (n=45) were identified. These were compared with non-cases and interview transcripts interrogated. NRS ratings of average breathlessness were assessed for fit to Peak/End rule.

RESULTS

Patients in the paradoxical average group had higher Chronic Respiratory Questionnaire physical domain scores on average p=0.042). Peak/End rule analysis showed high positive correlation (Spearman's rho=0.756, p<0.001).

CONCLUSIONS

The NRS requires further standardisation with reporting of question order and construction of scale used to enable informed interpretation. The application of the Peak/End rule demonstrates fallibility of NRS-Average as a construct as it is affected by current breathlessness. Measurement of breathlessness is important for both clinical management and research, but standardisation and transparency are required for meaningful results.

Symptoms and the body: Taking the inferential leap

The relationship between the conscious experience of physical symptoms and indicators of objective physiological dysfunction is highly variable and depends on characteristics of the person, the context and their interaction. This relationship often breaks down entirely in the case of "medically unexplained" or functional somatic symptoms, violating the basic assumption in medicine that physical symptoms have physiological causes. In this paper, we describe the prevailing theoretical approach to this problem and review the evidence pertaining to it. We then use the framework of predictive coding to propose a new and more comprehensive model of the body-symptom relationship that integrates existing concepts within a unifying framework that addresses many of the shortcomings of current theory. We describe the conditions under which a close correspondence between the experience of symptoms and objective physiology might be expected, and when they are likely to diverge. We conclude by exploring some theoretical and clinical implications of this new account.

The Specificity of Health-Related Autobiographical Memories in Patients With Somatic Symptom Disorder

OBJECTIVE

Patients with somatic symptom disorder (SSD) have persistent distressing somatic symptoms that are associated with excessive thoughts, feelings, and behaviors. Reduced autobiographical memory specificity (rAMS) is related to a range of emotional disorders and is considered a vulnerability factor for an unfavorable course of pathology. The present study investigated whether the specificity of health-related autobiographical memories is reduced in patients with SSD with medically unexplained dyspnea complaints, compared with healthy controls.

METHODS

Female patients with SSD (n = 30) and matched healthy controls (n = 24) completed a health-related Autobiographical Memory Test, the Beck Depression Inventory, the Ruminative Response Scale, and rumination scales concerning bodily reactions. Depressive symptoms and rumination were assessed because both variables previously showed associations with rAMS.

RESULTS

Patients with SSD recalled fewer specific (F(1,52) = 13.63, p = .001) and more categoric (F(1,52) = 7.62, p = .008) autobiographical memories to health-related cue words than healthy controls. Patients also reported higher levels of depressive symptoms and rumination (all t > 3.00, p < .01). Importantly, the differences in memory specificity were independent of depressive symptoms and trait rumination.

CONCLUSIONS

The present study extends findings on rAMS to a previously unstudied sample of patients with SSD. Importantly, the presence of rAMS could not be explained by increased levels of depressive symptoms and rumination. We submit that rAMS in this group reflects how health-related episodes and associated symptoms are encoded in memory.

Accuracy and bias in retrospective symptom reporting

PURPOSE OF REVIEW

Self-reported bodily symptoms are of primary importance in healthcare and in health-related research. Typically, they are assessed in clinical interviews or by means of traditional questionnaire formats that require the respondent to provide retrospective symptom estimates rated along intuitive frequency and/or intensity standards and aggregated across varying or unspecified time windows.

RECENT FINDINGS

Retrospective symptom assessments are often biased when compared to (averaged) momentary assessments of symptoms. A variety of factors and conditions have been identified to influence the amount of bias in symptom reporting. Recent research has focused on the underlying mechanisms for the discrepancy between memory and experience. It is suggested that different types of questions and formats assess different types of information, and each may be relevant for different purposes. Knowledge of these underlying mechanisms also provides a relevant framework to better understand individual differences in symptom reporting, including somatoform and somatic symptom disorder.

SUMMARY

Accuracy of self-reported bodily symptoms is important for the clinician and the researcher. Understanding the mechanisms underlying bias may provide an interesting window to understand how symptom episodes are processed, encoded, and consolidated in memory and may also provide clues to modify symptom experiences.

Ambulatory and diary methods can facilitate the measurement of patient-reported outcomes

PURPOSE

Ambulatory and diary methods of self-reported symptoms and well-being have received increasing interest in recent years. These methods are a valuable addition to traditional strategies for the assessment of patient-reported outcomes (PROs) in that they capture patients' recent symptom experiences repeatedly in their natural environments. In this article, we review ways that incorporating diary methods into PRO measurement can facilitate research on quality of life.

METHODS

Several diary methods are currently available, and they include "real-time" (Ecological Momentary Assessment) and "near-real-time" (end-of-day assessments, Day Reconstruction Method) formats. We identify the key benefits of these methods for PRO research.

RESULTS

(1) In validity testing, diary assessments can serve as a standard for evaluating the ecological validity and for identifying recall biases of PRO instruments with longer-term recall formats. (2) In research and clinical settings, diaries have the ability to closely capture variations and dynamic changes in quality of life that are difficult or not possible to obtain from traditional PRO assessments. (3) In test construction, repeated diary assessments can expand understanding of the measurement characteristics (e.g., reliability, dimensionality) of PROs in that parameters for differences between people can be compared with those for variation within people.

CONCLUSIONS

Diary assessment strategies can enrich the repertoire of PRO assessment tools and enhance the measurement of patients' quality of life.

Subjective evaluation of experimental dyspnoea--effects of isocapnia and repeated exposure

Resistive respiratory loading is an established stimulus for the induction of experimental dyspnoea. In comparison to unloaded breathing, resistive loaded breathing alters end-tidal CO2 (P(ET)CO2), which has independent physiological effects (e.g. upon cerebral blood flow). We investigated the subjective effects of resistive loaded breathing with stabilized P(ET)CO2 (isocapnia) during manual control of inspired gases on varying baseline levels of mild hypercapnia (increased P(ET)CO2). Furthermore, to investigate whether perceptual habituation to dyspnoea stimuli occurs, the study was repeated over four experimental sessions. Isocapnic hypercapnia did not affect dyspnoea unpleasantness during resistive loading. A post hoc analysis revealed a small increase of respiratory unpleasantness during unloaded breathing at +0.6 kPa, the level that reliably induced isocapnia. We did not observe perceptual habituation over the four sessions. We conclude that isocapnic respiratory loading allows stable induction of respiratory unpleasantness, making it a good stimulus for multi-session studies of dyspnoea.