Steven De Peuter

Inaccurate perception of asthma symptoms: a cognitive-affective framework and implications for asthma treatment.

Inaccurate perception of respiratory symptoms is often found in asthma patients. Typically, patients who inaccurately perceive asthma symptoms are divided into underperceivers and overperceivers. In this paper we point out that this division is problematic. We argue that little evidence exists for a trait-like stability of under- and overperception and that accuracy of respiratory symptom perception is highly variable within persons and strongly influenced by contextual information. Particularly, expectancy and affective cues appear to have a powerful influence on symptom accuracy. Based on these findings and incorporating recent work on associative learning, attention and mental representations in anxiety and symptom perception, we propose a cognitive-affective model of symptom perception in asthma. The model can act as a framework to understand both normal perception as well as under- and overperception of asthma symptoms and can guide the development of affect-related interventions to improve perceptual accuracy, asthma control and quality of life in asthma patients.

Sigh rate and respiratory variability during mental load and sustained attention

Spontaneous breathing consists of substantial correlated variability: Parameters characterizing a breath are correlated with parameters characterizing previous and future breaths. On the basis of dynamic system theory, negative emotion states are predicted to reduce correlated variability whereas sustained attention is expected to reduce total respiratory variability. Both are predicted to evoke sighing. To test this, respiratory variability and sighing were assessed during a baseline, stressful mental arithmetic task, nonstressful sustained attention task, and recovery in between tasks. For respiration rate (excluding sighs), reduced total variability was found during the attention task, whereas correlated variation was reduced during mental load. Sigh rate increased during mental load and during recovery from the attention task. It is concluded that mental load and task-related attention show specific patterns in respiratory variability and sigh rate.

Distorted Symptom Perception in Patients With Medically Unexplained Symptoms

The present study investigated differences in symptom perception between a clinical sample with medically unexplained symptoms (MUS) and a matched healthy control group. Participants (N = 58, 29 patients) were told that they would inhale different gas mixtures that might induce symptoms. Next, they went through 2 subsequent rebreathing trials consisting of a baseline (60 s room air breathing), a rebreathing phase (150 s, which gradually increased ventilation, PCO2 in the blood, and perceived dyspnea), and a recovery phase (150 s, returning to room air breathing). Breathing behavior was continuously monitored, and dyspnea was rated every 10 s. The within-subject correlations between dyspnea on the one hand and end-tidal CO2 and minute ventilation on the other were used to index the degree to which perceived dyspnea was related to specific relevant respiratory changes. The results showed that perceived symptoms were less strongly related to relevant physiological parameters in MUS patients than in healthy persons, specifically when afferent physiological input was relatively weak. This suggests a stronger role for top-down psychological processes in the symptom perception of patients with MUS.

Negative affectivity and the influence of suggestion on asthma symptoms

OBJECTIVE To investigate the effect of suggestion on subjective and objective asthma symptoms as a function of negative affectivity of the patients. METHODS Asthmatics (n=32) took puffs from three separate placebo inhalers, being described as an inert (practice) substance, a bronchoconstrictor, and a bronchodilator. Negative affectivity, social desirability, probability of medication-intake, intensity of asthma symptoms and total respiratory resistance were measured at onset. The latter three measures were repeated after each trial. Heart rate, end tidal PCO(2), and breathing behaviour were measured during each trial. RESULTS Asthmatics with high negative affectivity had overall more intense asthma symptoms. They also reported more airway obstruction after suggested bronchoconstriction and less after suggested bronchodilation, whereas persons with low negative affectivity did not show such variation. These effects were unrelated to social desirability. Respiratory symptoms correlated with the odds of medication intake. Neither negative affectivity nor suggestion influenced lung function and only breathing parameters under voluntary control changed as a function of suggestion. CONCLUSION Self-reported symptoms of asthmatics with high negative affectivity are more influenced by suggestion than those of patients with low negative affectivity.

Can subjective asthma symptoms be learned

Objective: We investigated whether perception of subjective asthma symptoms can be brought under control of biomedically irrelevant cues in the environment, i.e., whether subjective asthma symptoms can be learned in response to harmless stimuli. Methods: Twenty patients with asthma and 20 healthy participants were presented with two placebo-inhalers presented as new chemicals for diagnosing asthma. One inhaler was coupled three times with rebreathing 5% CO2 in oxygen, the other inhaler was coupled three times with rebreathing oxygen. In the subsequent test phase, both inhalers were coupled once with oxygen. We assessed airway resistance and subjective symptoms throughout the study. Results: Both groups expected and reported more symptoms with the inhaler that was previously associated with the CO2 trials compared with trials with the inhaler that was used on trials without CO2 without concomitant effects on respiratory resistance. The learning effects were most pronounced in a subgroup of patients reporting symptoms of hyperventilation during asthma exacerbations in daily life. Conclusions: Subjective respiratory symptoms can be learned in response to harmless stimuli and a substantial proportion of patients with asthma might be especially vulnerable to this phenomenon. Because asthma patients rely mainly on perceived symptoms for their medication use, it is likely that they will take reliever medication based on expected symptoms instead of real exacerbations of respiratory dysfunction. ASC = Asthma Symptom Checklist; ANX = ASC anxiety subscale; DYS = ASC dyspnea subscale; FAT = ASC fatigue subscale; FOT = forced oscillation technique; HYP = ASC hyperventilation subscale; IRR = ASC irritability subscale; NA = negative affectivity; OBS = ASC obstruction subscale; VAS = visual analog scale.

Verdere validering van de Positive and Negative Affect Schedule (PANAS) en vergelijking van twee Nederlandstalige versies

Further validation of the Positive and Negative Affect Schedule (PANAS) and comparison of two Dutch versionsThe first aim of this study was to evaluate the reliability and validity of one version of the PANAS that is widely used in Flanders. In a large nonclinical sample (N=3499), the PANAS showed solid psychometric properties. Sex differences appeared: men scored significantly higher on Positive Affect (PA), but significantly lower on Negative Affect (NA), in comparison with women. Six models were tested with Confirmatory Factor Analysis (CFA). The best-fitting model consisted of two correlated factors corresponding to the PA and NA scales and permitted correlated error. Consequently the hypothesis of complete independence between PA and NA must be rejected. In a second part, we compared our version with a Dutch version (Peeters, Ponds & Vermeeren, 1996). Both translations differed regarding nine items. Our analysis confirmed the psychometric properties of the latter version, and CFA indicated the same model as best-fitting model. Inspection on the item level revealed no considerable differences between the two versions.

Accuracy of respiratory symptom perception in persons with high and low negative affectivity

Accuracy of respiratory symptom perception was investigated in different contexts in participants (N = 56) scoring high or low for negative affectivity (NA). Within subject-correlations were calculated between minute ventilation (frequency per minute × tidal volume) and the subjective symptom ‘faster and/or deeper breathing’ across 10 subsequent breathing trials of 2 min with varying air mixtures, containing fresh or foul smelling odours and/or 5.5% CO2. Half the participants were given a positive information frame for the sensations (‘some air mixtures may induce a pleasantly arousing feeling, like when being in love’), whereas the other half was given a negative frame (‘some air mixtures may induce feelings of being anxious and distressed’). Interoceptive accuracy was overall fairly high (r = 0.56–0.74), but it dropped considerably (r = 0.27), when bodily sensations were induced in high NA persons in a negative information frame (interaction, p < 0.005). Interoceptive accuracy appears low when persons with high NA are in situations characterised by negative affective cues.

Negative affective pictures can elicit physical symptoms in high habitual symptom reporters

The present study aimed to explore the role of a brief negative affective state on symptom reporting. Non-clinical high (n = 24) and low (n = 24) habitual symptom reporters viewed four picture series (160 s per series) varying in affective content: neutral, general positive, general negative and symptom-related. Participants rated each picture series on valence, dominance and arousal, and reported their affective state and somatic symptoms experienced during the series. Results showed that all participants reported higher levels of negative affect during the negative and symptom-related picture series compared with the positive and neutral picture series. Only high habitual symptom reporters also reported more bodily symptoms after viewing the negative and symptom-related pictures. The findings allude to a learned association between negative emotional states and symptom reporting in high habitual symptom reporters.

Why do you sigh? Sigh rate during induced stress and relief

Whereas sighing appears to function as a physiological resetter, the psychological function of sighing is largely unknown. Sighing has been suggested to occur both during stress and negative emotions, such as panic and pain, and during positive emotions, such as relaxation and relief. In three experiments, sigh rate was investigated during short imposed states of stress and relief. Stress was induced by exposure to a loud noise stressor or by anticipation of it. Relief was induced by the end of the stressor or the anticipation that no stressor would follow. Breathing parameters were recorded continuously by means of the LifeShirt System. Results consistently showed that more sighing occurred during conditions of relief compared to conditions of stress.

Air hunger and ventilation in response to hypercapnia: effects of repetition and anxiety

We investigated the effects of anxiety on the intensity of air hunger during gradually increasing levels of CO2 until the end-tidal fractional concentration of CO2 was 7.9% or air hunger was intolerable. Normal high and low (trait) anxious participants (N=23) went through three rebreathing trials (15 min interval). Breathing behaviour was continuously monitored and air hunger was rated every 12 s. The threshold for responding to the increased CO2 was always lower for the subjective rating than for the ventilatory response. Habituation across trials was observed for both the ventilatory response and the air hunger rating regardless of anxiety. However, beyond the threshold, the slope in air hunger ratings decreased across trials in low anxious persons and tended to increase in high anxious persons (interaction P<0.05). No differences occurred in the slopes of the breathing responses. The findings documented uncoupling of the physiological and subjective responses during CO2-induced air hunger.