Relationship Between Different Experimental Measures of Distorted Symptom Perception in Functional Syndrome Patients

Patients with functional somatic syndromes show reduced correspondence between induced physiological changes and self-reported symptoms in a rebreathing paradigm, as well as elevated symptoms unrelated to physiological changes after induction of negative affective states in an affective picture-viewing paradigm. Detailed results of both paradigms separately were published elsewhere. The main goal of the current report is to describe the relationship between the responses to these two paradigms measuring distortions in symptom perception in a well-described sample of patients with fibromyalgia and/or chronic fatigue syndrome.

Patients (N = 81) with fibromyalgia and/or chronic fatigue syndrome participated in a test session comprising four well-validated paradigms, including the picture-viewing and rebreathing paradigm. Using mixed model analyses, we tested whether the amount of affective modulation of symptom reporting was related to distorted perception of induced dyspnea. In an exploratory way, we assessed the role of several individual difference variables as moderators.

There was no relationship between patients' amount of affective modulation of symptom reporting, as assessed with the picture paradigm, and level of distortion in dyspnea perception, as assessed with the rebreathing paradigm (effect of affective modulation in the subjective recovery from induced dyspnea: F1,70 = 0.16, p = .70; time by affective modulation interaction effect: F4,70 = 0.14, p = .97).

Biased symptom reporting in one paradigm is unrelated to biased symptom reporting in the other paradigm, indicating that distortions in symptom perception in patients with functional somatic syndromes are not a trait-like, cross-situationally stable condition, but a versatile dysfunction that is context dependent.