Perception Of Respiratory Symptoms Research Articles

Laryngeal response to high-intensity exercise in healthy athletes

IntroductionExercise-induced laryngeal obstruction (EILO) is a common cause of exertional breathing problems. The current diagnostic approach rests on evaluation of laryngeal obstruction visualised by laryngoscopy performed continuously throughout a maximal...

Respiratory symptom perception during exercise in patients with heart failure with preserved ejection fraction

We investigated whether central or peripheral limitations to oxygen uptake elicit different respiratory sensations and whether dyspnea on exertion (DOE) provokes unpleasantness and negative emotions in patients with heart failure with preserved ejection fraction (HFpEF). 48 patients were categorized based on their cardiac output (Q̇c)/oxygen uptake (V̇O2) slope and stroke volume (SV) reserve during an incremental cycling test. 15 were classified as centrally limited and 33 were classified as peripherally limited. Ratings of perceived breathlessness (RPB) and unpleasantness (RPU) were assessed (Borg 0–10 scale) during a 20 W cycling test. 15 respiratory sensations statements (1–10 scale) and 5 negative emotions statements (1−10) were subsequently rated. RPB (Central: 3.5±2.0 vs. Peripheral: 3.4±2.0, p=0.86), respiratory sensations, or negative emotions were not different between groups (p>0.05). RPB correlated (p<0.05) with RPU (r=0.925), “anxious” (r=0.610), and “afraid” (r=0.383). While DOE provokes elevated levels of negative emotions, DOE and respiratory sensations seem more related to a common mechanism rather than central and/or peripheral limitations in HFpEF.

Relationship of computed tomography-based measurements with symptom perception and quality of life in patients with severe asthma

BackgroundSymptom perception and quality of life (QOL) are important domains for properly managing severe asthma. This study aimed to assess the relationship between airway structural and parenchymal variables measured using chest computed tomography (CT) and subjective symptom perception and QOL in patients with severe asthma enrolled in the Korean Severe Asthma Registry. MethodsThis study used CT-based objective measurements, including airway wall thickness (WT), hydraulic diameter, functional small airway disease (fSAD), and emphysematous lung (Emph), to assess their association with subjective symptom (cough, dyspnea, wheezing, and sputum) perception measured using the visual analog scale, and QOL measured by the Severe Asthma Questionnaire (SAQ). ResultsA total of 94 patients with severe asthma were enrolled in this study. The WT and fSAD% were significantly positively associated with cough and dyspnea, respectively. For QOL, WT and Emph% showed significant negative associations with the SAQ. However, there was no significant association between lung function and symptom perception or between lung function and QOL. ConclusionOverall, WT, fSAD%, and Emph% measured using chest CT were associated with subjective symptom perception and QOL in patients with severe asthma. This study provides a basis for clarifying the clinical correlates of imaging-derived metrics and for understanding the mechanisms of respiratory symptom perception.

The impact of emotional context on neural substrates of respiratory sensory gating.

Psychological challenges have been found to impact respiratory symptom perception in healthy individuals as well as in patients with various neurological disorders. Human respiratory sensory gating is an objective measure to examine respiratory sensory information processing of repetitive respiratory mechanical stimuli in the central nervous system. With this electrophysiological method, patients with higher anxiety levels showed reduced respiratory sensory gating function in the cortex, and increased symptom perception. In addition, positive emotional contexts were found to increase the respiratory sensory gating function using RREPs. However, neural substrates related to emotional impacts on respiratory sensory gating remain still unclear. In the present study, we examined the emotion processing of respiratory sensory gating using functional magnetic resonance imaging. We hypothesized that positive compared with neutral stimuli would result in reduced brain activations in cortical areas with the paired occlusion paradigm. Thirty-five healthy adults participated in this event-designed fMRI experiment. Paired inspiratory occlusions (two transient occlusions with a 500 ms inter-stimulus-interval are delivered during one inspiration) were provided using an external trigger outside of the scanner. At least 40 paired inspiratory occlusions were collected for each trial. The experiment contained three runs during which participants underwent 12 min for the paired inspiratory occlusion paradigm while watching a fixation cross (the control condition), neutral and positive emotional picture series. The order of emotional picture series was randomized across the participants. Our results revealed an overall trend of reduction of brain activity from the neutral (minus fixation) condition, to the pleasant (minus fixation) condition. For bilateral thalamus and primary visual cortices, there was no significant difference in neural activation between the two contrasts of pleasant (ContrastP-F) and neutral condition (ContrastN-F). The activation of the mid-cingulate and the orbitofrontal cortex was lower in ContrastP-F compared to ContrastN-F. In conclusion, our results suggest that emotional context, especially positive valence, modulates neural correlates in middle cingulate cortex and orbitofrontal cortex in terms of respiratory sensory gating. Future studies are recommended to test emotional impacts on respiratory sensations in patients with neurological disorders.

Beware of Dog: Practical Consideration in Asthmatic Patients with Poor Perception of Respiratory Symptoms

Symptoms are often difficult to quantify, represent and depict for the patients and sometime also for the attending physicians. Anyway their role is crucial in influencing the relationship patient/physician in many ways. Respiratory symptoms (cough, thoracic pain, dispnoea) are not free of this challenging drawback. In asthmatic patients the subjective awareness of their disease condition, expecially their insight in the quality of breathing pattern, is critical to assess severity and control of their disease: under-perception of respiratory symptoms make this task problematic for patients and physicians. To estimate the magnitude of problem two set of reports have been examined: one on “real life” patients with chronic stable asthma and secondly studies evaluating the level of perception in selected asthmatic patients in a laboratory setting using bronchial provocation tests tool. Cumulatively a rough percentage of 20% asthmatic patients showed a reduced ability to be aware of their low level of pulmonary function. This impaired ability to perceive and report symptoms could also be a harbinger of undesirable and sometimes dangerous consequences. These data show that poor perception in asthma is a challenging problem affecting a large proportion of patients, with the potential of severe outcomes that need to be accurately addressed.

Expectation and dyspnoea: the neurobiological basis of respiratory nocebo effects.

Cues such as odours that do not per se evoke bronchoconstriction can become triggers of asthma exacerbations. Despite its clinical significance, the neural basis of this respiratory nocebo effect is unknown.We investigated this effect in a functional magnetic resonance imaging (fMRI) study involving 36 healthy volunteers. The experiment consisted of an experience phase in which volunteers experienced dyspnoea while being exposed to an odorous gas ("Histarinol"). Volunteers were told that Histarinol induces dyspnoea by bronchoconstriction. This was compared with another odorous gas which did not evoke dyspnoea. Dyspnoea was actually induced by a concealed, resistive load inserted into the breathing system. In a second, expectation phase, Histarinol and the control gas were both followed by an identical, very mild load. Respiration parameters were continuously recorded and participants rated dyspnoea intensity after each trial.Dyspnoea ratings were significantly higher in Histarinol compared with control conditions, both in the experience and in the expectation phase, despite identical physical resistance in the expectation phase. Insula fMRI signal matched the actual load, i.e. a significant difference between Histarinol and control in the experience phase, but no difference in the expectation phase. The periaqueductal gray showed a significantly higher fMRI signal during the expectation of dyspnoea. Finally, Histarinol-related deactivations during the expectation phase in the rostral anterior cingulate cortex mirrored similar responses for nocebo effects in pain.These findings highlight the neural basis of expectation effects associated with dyspnoea, which has important consequences for our understanding of the perception of respiratory symptoms.

Beware of Dog: Practical Consideration in Asthmatic Patients with Poor Perception of Respiratory Symptoms

Symptoms are often difficult to quantify, represent and depict for the patients and sometime also for the attending physicians. Anyway their role is crucial in influencing the relationship patient/physician in many ways. Respiratory symptoms (cough, thoracic pain, dispnoea) are not free of this challenging drawback. In asthmatic patients the subjective awareness of their disease condition, expecially their insight in the quality of breathing pattern, is critical to assess severity and control of their disease: under-perception of respiratory symptoms make this task problematic for patients and physicians. To estimate the magnitude of problem two set of reports have been examined: one on “real life” patients with chronic stable asthma and secondly studies evaluating the level of perception in selected asthmatic patients in a laboratory setting using bronchial provocation tests tool. Cumulatively a rough percentage of 20% asthmatic patients showed a reduced ability to be aware of their low level of pulmonary function. This impaired ability to perceive and report symptoms could also be a harbinger of undesirable and sometimes dangerous consequences. These data show that poor perception in asthma is a challenging problem affecting a large proportion of patients, with the potential of severe outcomes that need to be accurately addressed.

Respiratory modulation of intensity ratings and psychomotor response times to acoustic startle stimuli

Respiratory interoception may play an important role in the perception of respiratory symptoms in pulmonary diseases. As the respiratory cycle affects startle eye blink responses, startle modulation may be used to assess visceral-afferent signals from the respiratory system. To ascertain the potential impact of brainstem-relayed signals on cortical processes, we investigated whether this pre-attentive respiratory modulation of startle (RMS) effect is also reflected in the modulation of higher cognitive, evaluative processing of the startle stimulus. Twenty-nine healthy volunteers received 80 acoustic startle stimuli (100 or 105 dB(A); 50 ms), which were presented at end and mid inspiration and expiration, while performing a paced breathing task (0.25 Hz). Participants first responded to the startle probes by ‘as fast as possible’ button pushes and then rated the perceived intensity of the stimuli. Psychomotor response time was divided into ‘reaction time’ (RT; from stimulus onset to home button release; represents stimulus evaluation) and ‘movement time’ time (MT; from home button release to target button press). Intensity judgments were higher and RTs accelerated during mid expiration. No effect of respiratory cycle phase was found on eye blink responses and MTs. We conclude that respiratory cycle phase affects higher cognitive, attentional processing of startle stimuli.

Management of patients with obstructive lung disease in South India: a retrospective study of spirometry and bronchodilator use in an urban health centre

Background: Based on the burden of obstructive lung diseases program (BOLD), the global prevalence of chronic obstructive pulmonary disease (COPD) was 11.7% in which 90% of the deaths occur in low- and middle-income countries. India and China are estimated to account for 66% of total global COPD mortality. The Indian Chest Society (ICS) recommends spirometry to document irreversible airflow limitation in patients suspected of having COPD. However, the reported usage of spirometry among primary care physicians in India is only 10-20% as primary health care centers in India are not equipped with spirometry or inhaler devices.Methods: A retrospective study was done on patients treated for respiratory symptoms with bronchodilators at an urban health centre to document the practice pattern of primary care physicians with regards to use of spirometry in patients on bronchodilators.Results: Of the 1196 patients on bronchodilators, spirometry was documented in 15.5%. Patients on inhalers, using more than one therapy and males less than 55 years were more likely to undergo spirometry. About 52.4% of patients who underwent spirometry were found to have post bronchodilator forced expiratory volume at first second (FEV1)/ forced vital capacity (FVC) less than 0.7 of which 43% had severe disease and 44% had poor post-broncho-dilator reversibility.Conclusions: Besides diagnostic spirometry, management guidelines for COPD should be complemented by health education to change patients’ perception of respiratory symptoms, increase awareness of COPD in those with risk factors and change their health seeking behaviour along with continuous professional development activities for primary care physicians.

The triad of obstructive sleep apnea syndrome, COPD, and obesity: sensitivity of sleep scales and respiratory questionnaires.

ABSTRACTObjective:To investigate whether the presence of obstructive sleep apnea syndrome (OSAS) alters the perception of respiratory symptoms and quality of life in COPD patients, by using specific questionnaires, as well as to determine whether scales for assessing daytime sleepiness and for screening for OSAS can be used in the triad of OSAS, COPD, and obesity. Methods:We included 66 patients diagnosed with mild-to-moderate or severe COPD and presenting with a body mass index > 27 kg/m2. After polysomnography, patients completed the Epworth sleepiness scale (ESS), the Berlin questionnaire (BQ), the modified Medical Research Council (mMRC) scale, the Baseline Dyspnea Index (BDI), and the Saint George’s Respiratory Questionnaire (SGRQ). Results:Patients were first divided into two groups: COPD + OSAS (n = 46); and COPD-only (n = 20). The COPD + OSAS group was subdivided into a COPD + mild-to-moderate OSAS group (n = 32) and a COPD + severe OSAS group (n = 14), all of which were compared with the COPD-only group. There was a significant difference in mean FEV1 (L) between the COPD + OSAS groups and the COPD-only group (p = 0.073). The presence of the triad did not lead to significantly higher ESS scores, and scores > 10 had a specificity of 0.58. The BQ did not identify high risk for OSAS in the presence of the triad (specificity of 0.31). There were no significant differences in domain or total scores of the SGRQ between the COPD + OSAS groups and the COPD-only group. Conclusions:The confounding factors present in the triad of OSAS, COPD, and obesity prevented the perception of increased daytime sleepiness and high risk for OSAS. We observed no worsening of dyspnea perception or quality of life.

Perception of Asthma Symptoms as Assessed on the Visual Analog Scale in Subjects With Asthma: A Real-Life Study.

The perception of symptoms is a cornerstone in asthma management, but studies concerning this aspect provide conflicting evidence. The visual analog scale has been proposed as a useful tool for assessing perception of respiratory symptoms. The present study investigated whether visual analog scale assessment of perception of asthma symptoms was correlated to lung function or clinical features. This cross-sectional study enrolled 388 subjects with asthma (159 males; mean age 39.7 y). Perception of asthma symptoms was assessed by the visual analog scale; lung function was measured by spirometry. Asthma control was evaluated by the asthma control test. Anxiety and depression were evaluated on the Hospital Anxiety and Depression Scale questionnaire. Asthma was well controlled in 46.6% of subjects. Asthma symptoms in the prior month were reported by 59% of subjects; asthma signs were detected in 7.2%. The visual analog scale score was moderately correlated to FEV1 (r = 0.43). Subjects with bronchial obstruction had lower visual analog scale values than those without (P < .001). A visual analog scale score of 6 was a reliable cutoff point to discriminate subjects with bronchial obstruction (area under the curve = 0.71 at receiver operating characteristic curve; odds ratio [OR] = 7.58). Reported asthma symptoms (OR = 4.83), asthma signs (OR = 8.36), and anxiety (OR = 1.14) were predictive of a visual analog scale score of <6. This real-life study found that assessment of asthma symptoms by the visual analog scale might be a reliable tool in managing patients with asthma.

Self-reported Symptoms after Induced and Inhibited Bronchoconstriction in Athletes.

ABSTRACTPurposeA change in the perception of respiratory symptoms after treatment with inhaled beta2 agonists is often used to aid diagnosis of exercise-induced bronchoconstriction (EIB). Our aim was to test the association between subjective ratings of respiratory symptoms and changes in airway caliber after induced and inhibited bronchoconstriction in athletes with EIB.MethodsEighty-five athletes with diagnosed or suspected EIB performed a eucapnic voluntary hyperpnea (EVH) challenge with dry air. Of the 45 athletes with hyperpnea-induced bronchoconstriction [i.e., post-EVH fall in forced expiratory volume in 1 s (FEV1) ≥10%, EVH−], 36 were randomized in a double-blind, placebo-controlled, crossover study. Terbutaline (0.5 mg) or placebo was administered by inhalation 15 min before EVH. Spirometry (for FEV1) was performed before and after EVH, and respiratory symptoms were recorded 15 min after EVH on visual analog scales.ResultsTerbutaline inhibited bronchoconstriction (i.e., maximal fall in FEV1 <10% after EVH) in 83% of the EVH-positive athletes, with an average degree of bronchoprotection of 53% (95% confidence interval [CI], 45% to 62%). Terbutaline reduced group mean symptom scores (P < 0.01), but the degree of bronchoprotection did not correlate with individual differences in symptom scores between terbutaline and placebo. Of the 29 athletes who had less than 10% FEV1 fall after EVH in the terbutaline condition, almost half (48%) rated at least one respiratory symptom higher under terbutaline, and more than one quarter (28%) had a higher total symptom score under terbutaline.ConclusionSelf-reports of respiratory symptoms in conditions of induced and inhibited bronchoconstriction do not correlate with changes in airway caliber in athletes with EIB. Therefore, subjective ratings of respiratory symptoms after treatment with inhaled beta2 agonists should not be used as the sole diagnostic tool for EIB in athletes.

Respiratory Symptom Perception Differs in Obese Women With Strong or Mild Breathlessness During Constant-Load Exercise

During constant-load exercise, some otherwise healthy obese women report substantially more dyspnea on exertion (DOE) than do others. The objective of this study was to investigate whether qualitative differences exist between the sensations of dyspnea felt by these women. Seventy-eight women were categorized based on their ratings of perceived breathlessness (RPBs) (Borg 0-10 scale) after 6 min of 60-W cycling. Thirty-four women rated RPB ≥ 4 (+DOE) (34 ± 7 years, 36 ± 5 kg/m² BMI), and 22 women rated RPB ≤ 2 (-DOE) (32 ± 7 years, 37 ± 4 kg/m² BMI). Twenty-two women rated RPB as 3 (RPB = 3) (34 ± 7 years, 34 ± 4 kg/m² BMI) and were grouped separately to allow for a better delineation of the +DOE and the -DOE groups. After the exercise test, subjects were asked to pick three of 15 statements that best described their respiratory sensations. The +DOE and the -DOE groups were characterized differentially (P < .05) by the respiratory clusters "Breathing more" (82% of -DOE vs 41% of +DOE), "Shallow" (36% vs 6%), and "Heavy" (14% vs 53%). All four descriptors in the cluster "Work/Effort" were chosen more frequently by women in the +DOE group than by women in the -DOE group. Although relative exercise intensity was higher in the +DOE women (75% ± 13% vs 67% ± 10% of oxygen uptake at peak exercise, 41 ± 10 L/min vs 31 ± 8 L/min as % maximal voluntary ventilation, 83% ± 7% vs 76% ± 7% of peak heart rate), none of these variables was significantly associated with RPB. Not only is the intensity of dyspnea significantly different between the +DOE and the -DOE groups, but so are the self-reported qualitative aspects of their dyspnea. Women in the +DOE group reported an increased sensation of the work of breathing relative to women in the -DOE group, which may be associated with the elevated RPB.

The impact of emotions on symptom perception in patients with asthma and healthy controls

Accurate perception of respiratory symptoms is highly important for course and treatment of asthma. Recent findings suggest that emotions can greatly impact respiratory symptom perception. This study compared the impact of emotions on respiratory symptom perception between patients with asthma and matched healthy controls. Pleasant and unpleasant emotional states were elicited by viewing emotional picture series while symptom reports and respiratory parameters were measured. Greater symptom report was observed for the unpleasant compared to the pleasant emotional state that was not related to respiratory parameters. Notably, this effect was comparable between patients with asthma and healthy controls. The present results suggest that the impact of emotions on respiratory symptom perception is a rather general phenomenon and not dependent upon previous experiences with asthma symptoms.

The effect of anxiety on respiratory sensory gating measured by respiratory-related evoked potentials

Respiratory sensory gating is evidenced by decreased amplitudes of the respiratory-related evoked potentials (RREP) N1 peak for the second (S2) compared to the first occlusion (S1) when two paired occlusions are presented with a 500-millisecond (ms) inter-stimulus-interval during one inspiration. Because anxiety is prevalent in respiratory diseases and associated with altered respiratory perception, we tested whether anxiety can modulate individuals’ respiratory neural gating mechanism.By using high-density EEG, RREPs were measured in a paired inspiratory occlusion paradigm in 11 low and 10 higher anxious individuals with normal lung function.The N1 peak gating S2/S1 ratio and the N1 S2 amplitudes were greater in higher compared to low anxious individuals (p's<0.05). In addition, higher anxiety levels were correlated with greater S2/S1 ratios (r=0.54, p<0.05) and S2 amplitudes (r=−0.49, p<0.05).The results demonstrate that anxiety is associated with reduced respiratory sensory gating which might underlie altered respiratory symptom perception in anxious individuals.

Bronchial asthma

The aim of this review is to underline the need for an adequate clinical and functional evaluation of respiratory function and asthma control in patients undergoing surgical procedures requiring general anesthesia to obtain useful information for an adequate preoperative pharmacological approach. It has been shown that baseline uncontrolled clinical/functional conditions of airways represent the most important risk factors for perioperative bronchospasm. In nonemergency conditions, asthma patients should undergo clinical/functional assessment at least 1 week before the surgery intervention to obtain, the better feasible control of asthma symptoms in the single patient. Some simple preoperative information given by the patient in preoperative consultation may be sufficient to identify individuals with uncontrolled or poor controlled asthmatic conditions. Spirometric evaluation is essential in individuals with poor control of symptoms, as well as in those patients with uncertain anamnestic data or limited perception of respiratory symptoms, and in those requiring lung resection. A better control of asthma must be considered the 'gold standard' for a patient at 'a reasonable low risk' to develop perioperative/postoperative bronchospasm. International consensus promoted by pulmonologists, anesthesiologists, and allergists might be useful to define a better diagnostic and therapeutic approach.

The influence of fear of symptoms and perceived control on asthma symptom perception

ObjectiveSelf-reported asthma symptoms correlate only modestly with measures of underlying pathophysiological mechanisms. In this study, we investigated the role of fear of symptoms and perceived control on respiratory symptom perception in patients with asthma. MethodsPatients with intermittent to moderate persistent asthma (N=32) were administered 4 subsequent rebreathing challenges (one using 100% O2 and three using 5% CO2 and 95% O2). We manipulated perceived control by providing information on the availability/unavailability of rescue medication during the challenges (perceived control/no control condition). Perceived symptoms and lung function were assessed after each rebreathing challenge. ResultsPersons with low fear of symptoms reported respiratory symptoms to be less unpleasant during the perceived control condition compared to the no control condition. The reverse was found for persons with high fear of symptoms. The interaction between fear of symptoms and the control manipulations was mediated by threat perception. ConclusionMessages intended to increase perceived control over symptoms may actually increase threat in persons with high fear of symptoms and eventually increase unpleasantness of respiratory sensations. This finding underlines the importance of affective processes in the perception of asthma symptoms and shows that instructions to patients should take pre-existing fear levels into account.

The effect of anxiety on respiratory sensory gating measured by the respiratory related evoked potential (RREP)

Respiratory sensory gating is evidenced by decreased amplitude of the respiratory-related evoked potentials (RREP) N1 peak for the second occlusion (S2) when two 200-millisecond (msec) occlusions are presented with a 500-msec interval during inspiration. The N1 peak amplitude ratio of the S2 and first occlusion (S1), S2/S1, is less than 0.5 due to central neural sensory gating. We hypothesized that anxiety can modulate individuals' respiratory neural gating. We tested this hypothesis with the paired inspiratory occlusion protocol in 11 low and 10 high anxious individuals. Individuals were divided into the two groups based on their state anxiety scores obtained by the State-Trait Anxiety Inventory. The results showed a significant difference of the N1 peak gating S2/S1 ratio between the low anxious and high anxious group (0.28 ± 0.13 and 0.42 ± 0.16, respectively, p<0.05). A two-way ANOVA confirmed that this ratio difference was due to significantly lower S2 amplitudes in the low anxious group compared to the high anxious group (−1.31 ± 0.6 μV and −1.83 ± 0.59 μV, respectively). The results demonstrated that the respiratory sensory gating function was decreased in high anxious individuals. This suggests that anxiety was associated with increased neural throughput of redundant respiratory sensory information which might underlie altered respiratory symptom perception in anxious individuals.

Lung hyperinflation, perception of bronchoconstriction and airway hyperresponsiveness

To compare the influence of underlying airway inflammation and lung hyperinflation on dyspnea during induced bronchoconstriction in subjects with mild asthma (or asymptomatic airway hyperresponsiveness (AAHR). Fourteen mild asthmatic and 14 AAHR subjects had methacholine and 5'-adenosine monophosphate (AMP) challenges, and induced sputum analysis. Changes in inspiratory capacity (IC) and respiratory symptom scores were measured after challenges. Perception of respiratory symptoms was recorded on a modified Borg scale. The mean baseline FEV1, IC, mean provocative concentration of methacholine inducing a 20% decrease in FEV1 (PC20), the mean PC20 AMP and median inflammatory cell counts were similar in both groups. After methacholine, mean (+/-SD) reductions in FEV1 were 24.7+/-10.3% in mild asthma and 35.6+/-19.1% in AAHR (P>0.05); reductions in IC were, respectively, 10+/-12% and 24+/-20% (P>0.05); mean breathlessness scores at PC20 were 1.1 in mild asthma and 0 in AAHR P=0.003), and mean chest tightness scores were 1.2 in mild asthma and 0.8 in AAHR (P>0.05). Maximum chest tightness scores following MC correlated with the maximum decrease in IC in mild asthma (rs=0.75,P=0.009) and with the maximum decrease in FEV1 in AAHR (rs=0.60,P=0.04). After AMP, symptom scores were not significantly correlated with decreases in FEV1 or IC. The number of inflammatory cells was not correlated with decreases in IC after methacholine, AMP or with their PC20s, although inflammation was minimal in both groups. Lower breathlessness scores in AAHR compared to mild asthma were not explained by differences in lung hyperinflation nor in airway inflammation.

Differentiation between the sensory and affective aspects of histamine-induced bronchoconstriction in asthma

Respiratory symptom perception research has focused mainly on respiratory sensations. Because dyspnea is multidimensional, affective aspects should be investigated. Patients with asthma (N=25) underwent a histamine provocation until a 20% fall in forced expiratory volume in 1s (FEV(1)). After each dose level, 6 symptoms of dyspnea intensity and 6 symptoms of dyspnea affectivity were rated. Individual perceptual sensitivity was determined by calculating the linear slope between the fall in FEV(1) and the increase in the total symptom score, and for affective and sensory symptoms separately [Bijl-Hofland, Folgering, van den Hoogen, et al. Perception of bronchoconstriction in asthma patients measured during histamine challenge test. Eur Respir J 1999;14:1049-54]. Trait anxiety, baseline state anxiety, daily asthma symptoms and catastrophizing during an asthma exacerbation were also assessed. Sensitivity was unrelated to physiological indices of disease severity (i.e., baseline FEV(1) and histamine dose level at 20% fall in FEV(1)), whereas it was positively related to trait anxiety, state anxiety, daily asthma symptoms and catastrophic thinking during an asthma exacerbation in daily life. These relationships were overall much stronger for affective than for sensory symptom slopes. In stepwise multiple regressions, state anxiety was the best predictor of the affective symptom slopes, whereas catastrophic thinking during an asthma exacerbation was the best predictor for the sensory symptom slopes. The differentiation between sensory and affective components of dyspnea adds to the understanding of respiratory symptom perception in asthma.