Thomas Ritz — Page 2 | PubMed Health

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Implementation and interpretation of respiratory sinus arrhythmia measures in psychosomatic medicine: practice against better evidence?

Respiratory sinus arrhythmia (RSA) or high-frequency heart rate variability has been widely used as a noninvasive measure of cardiac vagal tone. However, their dependency on both respiration rate and tidal volume is largely ignored. Only a minority of studies published in Psychosomatic Medicine in recent years has implemented precautions for controlling respiration rate in RSA measures, and tidal volume effects were only rarely addressed. We discuss methodologic issues related to respiratory control methods and present data that demonstrate that both respiration rate and tidal volume contribute substantially to the within-individual RSA variance under conditions of variable breathing, with tidal volume contributing up to one third beyond respiration rate. Finally, we outline a respiratory control method for the time-domain index of RSA and review research pertaining to its reliability, validity, and experimental application.

Arrhythmia, Sinus↗

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The asthma trigger inventory: validation of a questionnaire for perceived triggers of asthma.

BACKGROUND: Asthma patients' perceptions of triggers have been explored in a largely unstructured fashion in the past. We therefore developed and validated a questionnaire of commonly perceived asthma triggers. METHODS: Two hundred forty-seven primary care patients with asthma filled in an asthma trigger survey together with questionnaires on demographics, asthma-relevant information, perceived control of asthma, and general health status. Factor structure of the item pool and psychometric properties of trigger subscales were evaluated. We also investigated the relationship between allergen or psychological trigger reports and allergy skin test response or respiratory impedance during emotional film viewing, respectively. RESULTS: Principal component analysis yielded six factors that were thematically associated with psychology, animal allergens, pollen allergens, physical activity, infection, and air pollution/irritants. Subscales showed good internal consistencies and low to moderately positive intercorrelations. Psychological triggers were consistently associated with less favorable health status, a reduced perception of asthma control, and greater medical treatment utilization. Animal allergen scores correlated positively with skin test responses to animal allergens. Respiratory impedance increases during emotional film clips were positively correlated with the psychological trigger subscale. CONCLUSION: The questionnaire is a reliable measure of commonly perceived asthma triggers. Aspects of patients' trigger reports reflect actual reactivity to specific trigger factors.

Adult↗