Stuart M. Hochron

The effects of suggestion and emotional arousal on pulmonary function in asthma: a review and a hypothesis regarding vagal mediation.

&NA; This paper reviews the empirical literature on the relation between asthma, suggestion, and emotion, and proposes the hypothesis that these effects are mediated parasympathetically. The literature indicates that, among asthmatics, suggestion can produce both bronchoconstriction and bronchodilation, and that stress can produce bronchoconstriction. The proportion of asthmatic subjects showing bronchoconstriction to both suggestion and stress averages 35%‐40% across studies, but, because of methodological considerations, might be conservatively estimated as closer to 20%. The effect is smaller for suggestion of bronchodilation, and is very short‐lived among nonasthmatics. No clear connection has been found between these responses and such subject variables as age, gender, asthma severity, atopy, or method of pulmonary assessment, although some nonsignificant tendencies appear. Most studies in this literature used small ns and did not systematically examine various somatic, environmental, and demographic factors that could influence results. A hypothesis is presented regarding vagal mediation of psychological effects on the airways, as well as possible alternative mechanisms, and recommendations for future research to evaluate these hypotheses.

Respiratory Sinus Arrhythmia Versus Neck/Trapezius EMG and Incentive Inspirometry Biofeedback for Asthma: A Pilot Study

This pilot study compared biofeedback to increase respiratory sinus arrhythmia (RSA) with EMG and incentive inspirometry biofeedback in asthmatic adults. A three-group design (Waiting List Control n = 5, RSA biofeedback n = 6, and EMG biofeedback n = 6) was used. Six sessions of training were given in each of the biofeedback groups. In each of three testing sessions, five min. of respiratory resistance and EKG were obtained before and after a 20-min biofeedback session. Additional five-min epochs of data were collected at the beginning and end of the biofeedback period (or, in the control group, self-relaxation). Decreases in respiratory impedance occurred only in the RSA biofeedback group. Traub-Hering-Mayer (THM) waves (.03-.12 Hz) in heart period increased significantly in amplitude during RSA biofeedback. Subjects did not report significantly more relaxation during EMG or RSA biofeedback than during the control condition. However, decreases in pulmonary impedance, across groups, were associated with increases in relaxation. The results are consistent with Vaschillos theory that RSA biofeedback exercises homeostatic autonomic reflex mechanisms through increasing the amplitude of cardiac oscillations. However, deep breathing during RSA biofeedback is a possible alternate explanation.

Panic symptoms in asthma and panic disorder : a preliminary test of the dyspnea-fear theory

Leys (Behaviour Research and Therapy, 27, 549-554, 1989) dyspnea-fear theory was tested on three groups of subjects: 10 with panic disorder, 24 with asthma, and 12 who were nonanxious and nonasthmatic, using measures of pulmonary function, muscle tension; and self-report measures of generalized anxiety, dyspnea, and psychopathology. Results are supportive of dyspnea-fear theory for asthmatics but not for individuals with panic disorder. Differences between groups on panic/fear measures were explained by a combination of general anxiety and dyspnea. Within-group regression analyses showed that only generalized anxiety symptoms contributed significantly to scores on the Asthma Symptom Checklist scale of panic/fear within the panic disorder group; while only dyspnea contributed to panic/fear among asthmatics. Additional results show that panic disorder subjects performed normally on pulmonary function tests but reported respiratory symptoms as severe as did asthmatics. Compared with normal subjects, both patient groups displayed lower correlations between self-rated symptoms of bronchoconstriction and objective pulmonary measures. Panic disorder subjects showed a negative relationship between pulmonary function and hyperventilation symptoms, suggesting a heightened sensitivity to, and discomfort with, sensations associated with normal pulmonary function. Asthmatics displayed a significant relationship between degree of airway obstruction and both trapezius surface EMG and ratings of hyperventilation symptoms.

Behavioral task-induced bronchodilation in asthma during active and passive tasks: a possible cholinergic link to psychologically induced airway changes.

This study investigated pulmonary and autonomic reactions to active and passive behavioral laboratory tasks among asthmatic subjects.It also examined the relationship between airway irritability, as measured by the methacholine challenge test (MCT), and autonomic activity and reactivity to these tasks. Fifty-one asthmatic and 37 nonasthmatic subjects were exposed to psychological laboratory tasks involving either active (mental arithmetic and reaction time) or passive (films depicting shop accidents and thoracic surgery) response. The MCT was given to asthmatics in a separate session. Active tasks reduced respiratory impedance, as measured by forced oscillation pneumography. They also increased heart rate and appeared to block vagal activity, as measured by respiratory sinus arrhythmia (RSA). Airway irritability as assessed by the MCT was positively related to amplitude of RSA and to skin conductance levels. Our data suggest that active and passive behavioral tasks may produce different pulmonary effects among both asthmatic and nonasthmatic individuals. Engaging in tasks requiring active responses may produce temporary improvements in pulmonary function. No autonomic differences were obtained between asthmatics and nonasthmatics in physiological response to stress, but greater cholinergic receptor sensitivity was suggested among high responders to methacholine.

Psychological approaches to the treatment of asthma

Outcome literature on psychological treatment for asthma covers psychoeducational self-management programs, relaxation therapy, biofeedback, and family therapy. Psychoeducational approaches now being standardized in a national program are cost-effective. They produce improved adjustment, increased medication compliance, greater perceived self-competence in managing symptoms, and decreased use of medical services. Significant effects have been found for relaxation therapy, although it is not clear whether the effectiveness depends on whole-body relaxation or specifically facial- or respiratory-muscle relaxation. Family therapy is helpful to some asthmatics. Active components in these methods remain to be identified as do the populations whom they can best serve. Biofeedback for respiratory resistance, trachea sounds, and vagal tone shows promise but has not been given adequate clinical testing.

Relaxation decreases large-airway but not small-airway asthma

Eleven asthmatic subjects were each offered sixteen sessions of relaxation therapy, consisting of progressive relaxation, desensitization, and EMG biofeedback to the trapezius and frontalis areas, while 9 subjects were offered a complex placebo. Subjects in the relaxation condition showed greater improvement than subjects in the placebo condition in performance on a methacholine challenge test which, as a measure of airway reactivity, reflects degree of asthma. Subjects in both conditions showed improvements in various self-report measures of asthma symptoms and psychopathology. Subject in the relaxation condition reported a significantly greater decrease in frequency of emotional precursors to asthma attacks than subjects in the control condition. Overall improvement on the methacholine challenge test was predicted almost perfectly by heliox spirometry. Only subjects showing predominant large-airway obstruction obstruction improved on the methacholine challenge test. The relative contribution of large airway obstruction to asthma was found to correlate with psychopathology.

Defensiveness and individual response stereotypy in asthma

Objective Previous literature has shown that the psychological trait of defensiveness is related to elevated sympathetic reactivity to stress and to several cardiac risk factors. The aim of this study was to examine whether these previous findings on defensiveness extend to an asthmatic population. Methods Defensiveness was measured by the Marlowe-Crowne Social Desirability Scale using a quartile split: high (upper 25%) and low (bottom 75%). Twenty-two defensive and 66 nondefensive participants with asthma were exposed to laboratory tasks (initial baseline rest period, reaction time task, and a shop accident film). Results During the tasks there was evidence of lower skin conductance levels and greater respiratory sinus arrhythmia amplitudes among defensive patients with asthma. After exposure to the tasks, defensive patients with asthma showed a decline on spirometry test measures compared with nondefensive asthmatic patients, who displayed an increase. Conclusions These data confirm individual response stereotypy and suggest that defensiveness may be characterized by sympathetic hypoarousal and parasympathetic hyperarousal among patients with asthma. Future studies are needed to determine whether defensiveness is a risk factor for stress-induced bronchoconstriction.

THE ASTHMA SYMPTOM PROFILE: A PSYCHOPHYSICALLY BASED SCALE FOR ASSESSMENT OF ASTHMA SYMPTOMS

The Asthma Symptom Profile (ASP) assesses phasic changes in three dimensions of asthma symptoms: intensity, unpleasantness, and quality of sensations. Quantification data on verbal descriptors were gathered from 46 adult asthmatics for each of these scales, using bimodality scaling: i.e., with numerical estimates and drawing lines varying length. Close agreement was obtained between these two modalities. The ASP was analyzed before and after a bronchodilator in 44 asthmatics using ipratropium bromide (IB). Forty of these subjects were also tested in a placebo condition. Although ASP changes produced by IB were no greater than those produced by the placebo, correlations with changes in spirometry variables were significant. There were no significant differences in correlations with line drawings vs. numerical ratings. The ASP appears to be useful measure of phasic changes in asthma symptoms. Asthmatics with mild airway obstruction do not appear to be able to discriminate small changes in airway function.

The effect of facial and trapezius muscle tension on respiratory impedance in asthma

This study tested two theories about the relationship between voluntary changes in muscle tension and pulmonary function in asthma. Kotses has theorized that decreased facial muscle tension decreases respiratory impedance via a hypothesized vagaltrigeminal reflex, but that muscle tension in other muscle groups has no such effect. Others have suggested that decreased thoracic muscle tension improves pulmonary function. Subjects were 19 volunteer asthmatic adults. They performed 3-minute cycles of deliberate muscle contraction, alternating two each for the shoulder and forehead muscles, followed by dominant forearm contraction. Surface EMG was measured from the frontalis and right trapezius areas. Airway impedance was measured by forced oscillation pneumography. Cardiac interbeat interval and respiratory sinus arrhythmia were measured to assess vagal tone. Frequency dependence of respiratory impedance increased during shoulder tension, giving some support to the theory relating thoracic tension to impairment in pulmonary function. Correlational analyses suggested a negative relationship between changes in cardiac interbeat interval and both frontalis muscle tension and decreased compliance of tissues in the airways. These findings are the opposite of those predicted by the vagal-trigeminal reflex theory.

Hypnotic Susceptibility and its Relationship to Outcome in the Behavioral Treatment of Asthma: Some Preliminary Data

12 subjects from an experiment on relaxation therapy for asthma were given the Harvard Group Scale of Hypnotic Susceptibility, Form A. Full scale hypnotic susceptibility scores were positively correlated, at a borderline significance, with improvement in the methacholine challenge test, a measure of asthma severity. Performance on the amnesia item of the Harvard Group Scale was correlated with improvement in self-reported symptoms of asthma.