Modulación del sistema defensivo en pacientes con fibromialgia

Abstract

The aim of this thesis was to study the response of the defensive system in patients with fibromyalgia through different psychophysiological indexes: defensive reflexes, heart rate variability and brain oscillations. Additionally, we have studied whether a cognitive-behavioral intervention could modify physiological, emotional and behavioral disorders of these patients. For this purpose, we have conducted four studies. The first two ones were focused on the study of the autonomic nervous system response by using heart rate variability indices in patients with fibromyalgia, patients with chronic back pain and healthy volunteers under three experimental conditions: rest, paying attention to pain and during paced breathing. The first study showed that both groups of patients (fibromyalgia and chronic back pain) exhibited lower heart rate variability than healthy volunteers. In addition, patients with fibromyalgia showed an increase in heart rate variability when they were paying attention to their own pain. The second study evaluated the stability of the heart rate variability indices over time, as well as whether the severity of the symptoms was related to changes in heart rate variability. The results of this study indicated that the steady decrease in heart rate variability was more pronounced in patients with fibromyalgia than in patients with chronic back pain. Moreover, it was observed that this reduction correlated with high levels of pain and fatigue in patients with chronic back pain, but not in patients with fibromyalgia. The third study showed that patients with fibromyalgia had a significant decrease in affective modulation of defensive reflexes and parasympathetic autonomic activity and a significant increase in spectral power of brain oscillations during an emotional induction task by using virtual environments. Finally, it was found that patients with fibromyalgia improved their mood, reduced their pain interference and increased their heart rate variability after a cognitive behavioral intervention. The findings of these studies seem to suggest that patients with fibromyalgia have significant disturbances in the defense system responses in different contexts and that these perturbations can be modified using a cognitive behavioral intervention.