The latent structure of the functional dyspepsia symptom complex: a taxometric analysis.

OBJECTIVES: Rome III introduced a subdivision of functional dyspepsia (FD) into postprandial distress syndrome and epigastric pain syndrome, characterized by early satiation/postprandial fullness, and epigastric pain/burning, respectively. However, evidence on their degree of overlap is mixed. We aimed to investigate the latent structure of FD to test whether distinguishable symptom-based subgroups exist. METHODS: Consecutive tertiary care Rome II FD patients completed the dyspepsia symptom severity scale. Confirmatory factor analysis (CFA) was used to compare the fit of a single factor model, a correlated three-factor model based on Rome III subgroups and a bifactor model consisting of a general FD factor and orthogonal subgroup factors. Taxometric analyses were subsequently used to investigate the latent structure of FD. KEY RESULTS: Nine hundred and fifty-seven FD patients (71.1% women, age 41 ± 14.8) participated. In CFA, the bifactor model yielded a significantly better fit than the two other models (χ² difference tests both p < 0.001). All symptoms had significant loadings on both the general and the subgroup-specific factors (all p < 0.05). Somatization was associated with the general (r = 0.72, p < 0.01), but not the subgroup-specific factors (all r < 0.13, p > 0.05). Taxometric analyses supported a dimensional structure of FD (all CCFI<0.38). CONCLUSIONS AND INFERENCES: We found a dimensional rather than categorical latent structure of the FD symptom complex in tertiary care. A combination of a general dyspepsia symptom reporting factor, which was associated with somatization, and symptom-specific factors reflecting the Rome III subdivision fitted the data best. This has implications for classification, pathophysiology, and treatment of FD.

Treating primary insomnia: clinical effectiveness and predictors of outcomes on sleep, daytime function and health-related quality of life.

Primary insomnia, as defined by DSM-IV-TR, refers to a persistent sleep disturbance which is not connected to a current psychiatric or physical condition, but significantly impairs social and occupational functioning. This study explored the impact of Cognitive Behavioral Therapy for Insomnia (CBT-i) on sleep, daytime functioning and health-related quality of life (HRQoL). Next, we investigated which factors predicted positive treatment outcome by examining demographics, insomnia characteristics, baseline levels of daytime function, HRQoL, sleep-disruptive beliefs and psychological health on post-treatment sleep quality, daytime function and HRQoL. 138 consecutive primary insomnia patients completed questionnaires pre- and post-treatment and at 6 months follow-up. After CBT-i, robust clinical improvements were observed in sleep, daytime function and HRQoL, regardless of age, gender, type or duration of the complaint. Patients with pre-treatment severe insomnia, pronounced daytime impairment and low psychological well-being benefited most.

Effects of a shortened asthma self-management group program.

OBJECTIVE: Asthma self-management programs are effective but often time-consuming.We evaluated the effects of a shortened asthma self-management program on asthma knowledge, morbidity and asthma-related behaviour in a group of moderate to severe adult asthmatics. METHODS: The effects of the program were evaluated with a one year prospective trial in a group of 55 asthmatics (mean age 45 yrs, 42% males, N=26 in intervention group, N=29 in control group) by administering questionnaires and diary exercises at baseline, immediately, 3 and 12 months after the end of the program. RESULTS: Asthma-related knowledge and hyperventilation symptoms improved more in the intervention than in the control group and this effect was maintained until 3 months after participation. General asthma symptoms improved significantly, but substantial symptom improvements were also found in the control group. The original effects in the intervention group persisted partly but not significantly 1 year after participation. No significant effects were found on pulmonary function. CONCLUSIONS: Based on our preliminary results, we conclude that our shortened asthma self-management program had an impact on knowledge and asthma symptoms, especially hyperventilation symptoms, until 3 months after the end of the program. Continuous reinforcement and specifying the program content are essential aspects to obtain more robust and long-lasting effects when administering shortened asthma self-management programs.

[Cognitive-behavioural therapy for primary insomnia: effectiveness in a clinical setting]. / Cognitieve gedragstherapie voor primaire insomnia: effectiviteit in een klinische setting.

BACKGROUND: The effectiveness of cognitive behavioural therapy for insomnia (cbt-i) has been demonstrated in randomised controlled trials (rct's) with primary insomnia patients and, more recently, with comorbid insomnia patients. The clinical impact of the treatment is mainly on sleep quality and the use of medication and to a lesser extent on daytime functioning. So far there have been very few studies of the effectiveness of cbt-i in clinical settings. AIM: To examine the effectiveness of cbt-i for primary insomnia via an uncontrolled prospective study in a clinical tertiary care setting. METHOD: We included 76 patients with primary insomnia, most of whom having been referred by their gp or medical specialist to the Leuven University Centre of Sleep, who followed a 6-week course of cbt-i as a group. Effects of cbt-i on primary and secondary outcome measures were studied. results cbt-i resulted in a significant improvement in all primary sleep variables such as sleep onset, sleep efficiency and sleep quality. The increase in total sleep time was less substantial, probably as a result of the specific sleep restriction guidelines. There was also a significant improvement on several secondary parameters, in particular dysfunctional cognitions, affective state, general health and use of medication. CONCLUSIONS: cbt-i has a significant impact on sleep quality, medication use and daytime functioning in primary insomniacs in a clinical tertiary care setting.

Smoking status moderates the contribution of social-cognitive and environmental determinants to adolescents' smoking intentions.

In this study, it was tested whether attitudes, self-efficacy, social influences and the perception of the school and home environments had different associations with intentions for adolescent non-smokers, occasional smokers and daily smokers. A regression model allowing for separate slopes of social-cognitive and environment variables accounted for 72% of the variation in intentions. For non-smokers, ease of refusing to smoke (beta = -0.06) and social influences favouring smoking (beta = 0.05) were linked to intentions. Occasional and daily smokers' intentions were associated with health consequences (beta = -0.05 and beta = -0.06, respectively) and ease of smoking/buying cigarettes (beta = 0.05 and beta = 0.24, respectively). Social influences favouring smoking (beta = 0.10) were also associated with intentions in daily smokers. In an extended model for current smokers (adjusted R(2) = 0.45), context-cued nicotine cravings (beta = 0.27) were linked to daily smokers', but not occasional smokers' intentions. The results suggest that motivating adolescents to abstain from or to quit smoking implies working on different combinations of determinants in non-smokers, occasional smokers and daily smokers. Interventions for daily smokers should supplement motivational techniques with stratagems that allow smokers to reduce the number of cravings they experience in specific contexts.

The role of physical workload and pain related fear in the development of low back pain in young workers: evidence from the BelCoBack Study; results after one year of follow up.

AIMS: To study the influence of work related physical and psychosocial factors and individual characteristics on the occurrence of low back pain among young and pain free workers. METHODS: The Belgian Cohort Back Study was designed as a prospective cohort study. The study population of this paper consisted of 716 young healthcare or distribution workers without low back pain lasting seven or more consecutive days during the year before inclusion. The median age was 26 years with an interquartile range between 24 and 29 years. At baseline, these workers filled in a questionnaire with physical exposures, work related psychosocial factors and individual characteristics. One year later, the occurrence of low back pain lasting seven or more consecutive days and some of its characteristics were registered by means of a questionnaire. To assess the respective role of predictors at baseline on the occurrence of low back pain in the following year, Cox regression with a constant risk period for all subjects was applied. RESULTS: After one year of follow up, 12.6% (95% CI 10.1 to 15.0) of the 716 workers had developed low back pain lasting seven or more consecutive days. An increased risk was observed for working with the trunk in a bent and twisted position for more than two hours a day (RR 2.2, 95% CI 1.2 to 4.1), inability to change posture regularly (RR 2.1, 95% CI 1.3 to 3.5), back complaints in the year before inclusion (RR 1.7, 95% CI 1.1 to 2.8), and high scores of pain related fear (RR 1.8, 95% CI 1.0 to 3.1). Work related psychosocial factors and physical factors during leisure time were not predictive. CONCLUSION: This study highlighted the importance of physical work factors and revealed the importance of high scores of pain related fear in the development of low back pain among young workers.

[Clinical application of portable spirometry in asthma].

OBJECTIVE: To investigate the clinical applications of portable spirometry in asthma. METHODS: Twenty patients with asthma were recruited from Peking Union Medical College Hospital. Flow-volume loop, simultaneous asthma symptoms, and mood were monitored three times a day for consecutive 14 days. RESULTS: In patients with a normal daytime spirometry, marked decline of forced expiratory volume in one second (FEV1) and peak expiratory flow (PEF) were observed at night and/or in the early morning. A within subject correlation analysis between FEV1, PEF, and asthma symptoms showed that the correlation between symptoms and airway obstruction was found only in seven out of twenty patients (35%). Four patients (20%) reported many symptoms with nearly normal portable spirometry. Accordingly, their symptoms were not correlated with FEV1 and PEF. This group of patients was defined as over-perceivers. On the contrary, another two patients (10%) did not report any symptoms while obvious airways obstruction was recorded by a portable spirometry. These patients were defined as under-perceivers. CONCLUSIONS: Dynamic monitoring of flow-volume loop with a portable spirometry is more accurate than routine lung function test in assessment of asthma severity. In addition, combined with simultaneous monitoring of symptoms, it would be of particularly helpful in identifying two specific types of asthma patients, e.g. over-perceivers and under-perceivers.

[Medically unexplained dyspnea in children: a review of 34 cases].

OBJECTIVE: Medically unexplained dyspnea is common in adult and accounts for 14% patients complaining of dyspnea. Its occurrence in children is seldom recognized. In the present paper, 34 children with medically unexplained dyspnea (age 10 to 18 years) seen in Peking Union Medical College Hospital from 1996 to 2002 are reported. METHODS: The diagnosis of medically unexplained dyspnea was clinical: it was based on the presence of dyspnea and other complaints which cannot be explained by an organic disease. The patients answered Nijmegen questionnaire and state and trait anxiety (STAI), and performed hyperventilation provocation test. Twenty sessions of breathing therapy were applied and 13 out of 34 children were followed up after the therapy. RESULTS: Among the children, 75% started to have symptoms at the age of 13 to 16 years, though the age of first episode could be as early as 8 years. In most of the cases, the course was chronic clinically. In addition to marked dyspnea, their clinical profile included symptoms of hyperventilation i.e. blurred vision, dizziness, tingling, stiff fingers or arm. The symptoms of anxiety were less frequent in children and accordingly the level of anxiety evaluated by means of STAI was lower in children compared to adult patients. The precipitating psychological factors appeared to be related to middle school competition. Pressure from exams, reprimand from stern and unsympathetic teachers coupled with high parental expectation could be emotionally damaging to psychologically susceptible children. Thirteen patients were followed up after 2-3 months of breathing therapy with emphasis on abdominal breathing and slowing down of expiration. After therapy, the sum score of the Nijmegen Questionnaire was markedly decreased. Dyspnea and symptoms of hyperventilation were improved. The level of anxiety was minimally modified. CONCLUSION: The cases illustrated the need for careful diagnostic evaluation and treatment because of the high rate of chronicity of the disorder.

Medically unexplained dyspnea: psychophysiological characteristics and role of breathing therapy.

BACKGROUND: Medically unexplained dyspnea occurs commonly in medical settings and remains poorly understood. This study was conducted to investigate the psychophysiological characteristics of medically unexplained dyspnea and the efficacy of breathing retraining for these patients. METHODS: A group of patients with medically unexplained dyspnea were compared to patients with a variety of organic lung diseases and healthy subjects. In another group of patients, the influence of breathing therapy on complaints, anxiety, and breath-holding was evaluated for an average of 1.5 years. RESULTS: Patients with medically unexplained dyspnea reported more intense dyspnea than patients with a variety of organic lung diseases. Additionally, they were anxious and presented a broad range of symptoms in daily life and under challenge, for instance voluntary hyperventilation. More than one third of them qualified for panic disorder. They had shorter breath-holding time at rest, less increase in breath-holding time and higher chances of showing a "paradoxical" decrease of breath-holding time after hyperventilation. A combination of PaO2, forced expiratory volume in one second (FEV1), and anxiety measures distinguished them from organic dyspnea. Breathing retraining profoundly improved their symptoms and decreased the level of state and trait anxiety. Moreover, they better tolerated the voluntary hyperventilation and the symptoms induced were also markedly decreased after therapy. Breath-holding time was prolonged and PetCO2 in a representative group of patients increased. CONCLUSIONS: Patients with medically unexplained dyspnea appear to have the feature of a "psychosomatic" patient: an anxious patient with a wide variety of symptoms of different organ systems that do not have an organic basis. They can be distinguished from organic dyspnea using a small set of physiological and psychological measures. Breathing retraining turns out to be an effective therapy for those "difficult to treat patients".

Evaluation of an individualised asthma programme directed at behavioural change.

An individualised asthma programme directed at behavioural change was evaluated in asthmatic subjects who reported complaints and impairment, despite adequate medical treatment. Mild-to-moderate asthma patients (n=23) were randomly assigned to a programme or waiting list condition. Outcome measures were: McMaster Asthma Quality of Life Questionnaire, Asthma Symptom Checklist, Negative Emotionality Scale, Knowledge, Attitude and Self-Efficacy Asthma Questionnaire, Adherence Scale, and peak flow measurements. Both groups were evaluated at three consecutive moments, each separated by 3 months; the programme was delivered between the first two evaluations. At onset the patient received a workbook containing information, exercises and homework assignments. Psycho-education, behavioural and cognitive techniques were introduced during six 1-h individual sessions. Compared with controls the programme group reported less symptoms (obstruction, fatigue), better quality of life (activity, symptoms, emotions), decreased negative affectivity, and increased adherence, immediately after finishing the programme and at 3 months follow-up. All three cognitive variables (knowledge, attitude towards asthma, self-efficacy) and day and night peak flow ratings improved in the programme group but not in the waiting list group. Participation in an individualised programme resulted in improvement of asthma morbidity, and asthma-related behaviour and cognitions, in subjects reporting symptoms and impairment despite adequate medical therapy.

Critical conditions for hyperventilation responses. The role of autonomic response propositions during emotional imagery.

Hyperventilation is often conceived of as part of a fight-or-flight response, triggered by situations with high arousal and negative valence. However, a previous study using emotional imagery found hyperventilation responses during imagery of high-arousal scenes regardless of their valence. Those imagery scripts contained suggestions of autonomic activity, which may have partly induced or enhanced the hyperventilatory responsivity. The present study used four emotional scripts--depicting relaxing, fearful, depressive, and pleasant situations--without suggestions of autonomic or respiratory responses. After each imagery trial, participants rated their imagery for valence, arousal, and vividness. Fractional end-tidal carbon dioxide (FetCO2), inspiratory and expiratory time, tidal volume, and pulse rate were measured in a non-intrusive way. Results showed significant FetCO2 drops during the fearful and pleasant scripts. However, this effect was much smaller compared to imagery scripts with autonomic response propositions. Participants imagining scripts without autonomic response information found it harder to imagine the scripts vividly and reported lower levels of subjective arousal.

Food likes and their relative importance in human eating behavior: review and preliminary suggestions for health promotion.

The present article reviews research about the psychological determinants of human eating behavior. A hypothetical model of food choice and intake is introduced, presenting various factors influencing eating behavior. Internal factors include sensory food aspects. Among the external factors are information, the social context and the physical environment. Processes such as mere exposure, Pavlovian conditioning and social learning shape the relationships between these factors, food liking and eating behavior. The relative contribution of the various determinants is discussed. In spite of a scarcity of studies, liking for the sensory aspects of food seems to be at the center of the development, maintenance and change of dietary patterns. Consequently, efforts for promoting healthy eating behavior might benefit from an increased attention towards learning principles and food likes in the development of interventions. Existing intervention strategies are criticized and preliminary suggestions are formulated to enhance their effectiveness.

Hyperventilation beyond fight/flight: respiratory responses during emotional imagery.

Hyperventilation (HV) is often considered part of a defense response, implying an unpleasant emotion (negative valence) combined with a strong action tendency (high arousal). In this study, we investigated the importance of arousal and valence as triggers for HV responses. Forty women imagined eight different scripts varying along the arousal and valence dimensions. The scripts depicted relaxation, fear, depressive, action, and desire situations. After each trial, the imagery was rated for valence, arousal, and vividness. FetCO2, inspiratory and expiratory time, tidal volume, and pulse rate were measured in a nonintrusive way. FetCO2 drops and decreases in inspiratory and expiratory time occurred in all but the depressive and the relaxation scripts, suggesting that a defense conceptualization of hyperventilation is not always appropriate.

Acquiring symptoms in response to odors: a learning perspective on multiple chemical sensitivity.

In this chapter, a learning account is discussed as a potential explanation for the symptoms in multiple chemical sensitivity. Clinical evidence is scarce and anecdotal. A laboratory model provides more convincing results. After a few breathing trials containing CO2-enriched air as an unconditioned stimulus in a compound with harmless odor substances as conditioned stimuli, subjective symptoms are elicited and respiratory behavior is altered by the odors only. Also, mental images can become conditioned stimuli to trigger subjective symptoms. The learning effects cannot be explained by a response bias or by conditioned arousal, and they appear to involve basic associative processes that do not overlap with aware cognition of the relationship between the odors and the CO2 inhalation. Learned symptoms generalize to new odors and they can be eliminated in a Pavlovian extinction procedure. In accordance with clinical findings, neurotic subjects and psychiatric cases are more vulnerable to learning subjective symptoms in response to odors. Consistent with a learning account, cognitive-behavioral treatment techniques appear to produce beneficial results in clinical cases. Several criticisms and unresolved questions regarding the potential role of learning mechanisms are discussed.

Hyperventilation and attention: effects of hypocapnia on performance in a stroop task.

This study aimed to investigate the effect of hypocapnia on attentional performance. Hyperventilation, producing hypocapnia, is associated with physiological changes in the brain and with subjective symptoms of dizziness, concentration problems and derealization. In this study (N=42), we examined cognitive performance on a Stroop-like task, following either 3 min of hypocapnic or normocapnic overbreathing. Both overbreathing trials were run on separate days, each preceded by a baseline trial with the same task during normal breathing. More and other symptoms were reported after hypocapnia compared to normocapnia. Also, more errors were made and progressively slower reaction times (RT's) were observed during recovery from hypocapnia. These performance deficits were only found in participants characterized by apneas. The number of symptoms did not correlate with RT's or errors. The pattern of data suggested that hypoxia, as a result of apneas during recovery from hypocapnia, caused the cognitive performance deficit.

A study of the relationship among self-reported noncompliance, symptomatology, and psychological variables in patients with asthma.

We examined the association among self-reported noncompliance and clinical status, symptomatology, functional activity, and psychological variables in asthma. Eighty-five asthmatics, who were hospitalized (H group), outpatients previously hospitalized (OH group), or outpatients not previously hospitalized (O group) completed questionnaires. Compliance was assessed during a structured interview. The higher prevalence of self-reported noncompliance in H group and OH group, compared to O group, was not explained by differences in respiratory function. Self-reported noncompliance was related to symptoms and emotional distress associated with disease and treatment, but not to functional or emotional status. A patient subgroup that catalogued itself as noncompliant may also be at risk for hospitalization, and was characterized by emotional distress associated with disease and treatment.

Psychosomatic symptoms and breathing pattern.

OBJECTIVE: Study of the links between breathing pattern, negative affectivity, and psychosomatic complaints at rest and following hyperventilation. METHODS: In 819 patients with anxiety and somatoform disorders and 159 healthy subjects, self-reported symptoms, breathing pattern, and end-tidal CO(2) concentration (FetCO(2)) were recorded during rest and following a hyperventilation provocation test (HVPT). The relationship between disorder category, symptoms, age, and score of STAI-trait (as a measure of negative affectivity) on the one hand, and breathing pattern on the other was investigated, separately in men and women. RESULTS: Anxiety disorders, and to a lesser extent, somatoform disorders, were characterized by breathing instability (progressive decrease of FetCO(2) at rest during mouthpiece breathing, delayed recovery of FetCO(2) following HVPT), the mean values of respiratory frequency, and FetCO(2) being modulated by STAI-trait. After grouping the symptoms into independent factors, links were observed between symptoms and breathing pattern, independently from the presence of an anxiety or somatoform disorder. CONCLUSION: Some symptom factors appeared to be related to a lower FetCO(2) during hyperventilation, others likely directly influenced the breathing pattern. Among those, mainly respiratory symptoms were accompanied by a reduction of FetCO(2) at rest, with slower recovery of FetCO(2) following HVPT. The latter was observed also in the presence of marked anxiety. In contrast, subjects complaining of dizziness, fainting, and paresthesias in daily life presented higher values of FetCO(2) following HVPT, probably due to a voluntary braking of ventilation during HVPT.

Generalization of acquired somatic symptoms in response to odors: a pavlovian perspective on multiple chemical sensitivity.

OBJECTIVE: Somatic symptoms that occur in response to odors can be acquired in a pavlovian conditioning paradigm. The present study investigated 1) whether learned symptoms can generalize to new odors, 2) whether the generalization gradient is linked to the affective or irritant quality of the new odors, and 3) whether the delay between acquisition and testing modulates generalization. METHODS: Conditional odor stimuli (CS) were (diluted) ammonia and niaouli. One odor was mixed with 7.4% CO2-enriched air (unconditional stimulus) during 2-minute breathing trials (CS+ trial), and the other odor was presented with air (CS- trial). Three CS+ and three CS- trials were conducted in a semirandomized order (acquisition phase). The test phase involved one CS+-only (CS+ without CO2) and one CS- test trial, followed by three trials using new odors (butyric acid, acetic acid, and citric aroma). Half of the subjects (N = 28) were tested immediately, and the other half were tested after 1 week. Ventilatory responses were measured during and somatic symptoms were measured after each trial. RESULTS: Participants had more symptoms in response to CS+-only exposures, but only when ammonia was used as the CS+. Also, generalization occurred: More symptoms were reported in response to butyric and acetic acid than to citric aroma and only in participants who had been conditioned. Both the selective conditioning and the generalization effect were mediated by negative affectivity of the participants. The delay between the acquisition and test phases had no effect. CONCLUSIONS: Symptoms that occur in response to odorous substances can be learned and generalize to new substances, especially in persons with high negative affectivity. The findings further support the plausibility of a pavlovian perspective of multiple chemical sensitivity.

Acquisition and extinction of somatic symptoms in response to odours: a Pavlovian paradigm relevant to multiple chemical sensitivity.

OBJECTIVES: Multiple chemical sensitivity is a poorly understood syndrome in which various symptoms are triggered by chemically unrelated, but often odorous substances, at doses below those known to be harmful. This study focuses on the process of pavlovian acquisition and extinction of somatic symptoms triggered by odours. METHODS: Diluted ammonia and butyric acid were odorous conditioned stimuli (CS). The unconditioned stimulus (US) was 7.4% CO2 enriched air. One odour (CS+) was presented together with the US for 2 minutes (CS+ trial), and the other odour (CS-) was presented with air (CS-trial). Three CS+ and three CS-exposures were run in a semi-randomised order; this as the acquisition (conditioning) phase. To test the effect of the conditioning, each subject then had one CS+ only--that is, CS+ without CO2--and one CS- test exposure. Next, half the subjects (n = 32) received five additional CS+ only exposures (extinction group), while the other half received five exposures to breathing air (wait group). Finally, all subjects got one CS+ only test exposure to test the effect of the extinction. Ventilatory responses were measured during and somatic symptoms after each exposure. RESULTS: More symptoms were reported upon exposure to CS+ only than to CS-odours, regardless of the odour type. Altered respiratory rate was only found when ammonia was CS+. Five extinction trials were sufficient to reduce the level of acquired symptoms. CONCLUSION: Subjects can acquire somatic symptoms and altered respiratory behaviour in response to harmless, but odorous chemical substances, if these odours have been associated with a physiological challenge that originally had caused these symptoms. The conditioned symptoms can subsequently be reduced in an extinction procedure. The study further supports the plausibility of a pavlovian conditioning hypothesis to explain the pathogenesis of MCS.