In a recent study published in the journal Behavioral Medicine, researchers from the University of Jaén, Spain, investigated interoceptive awareness in patients with fibromyalgia syndrome (FMS), a chronic pain condition accompanied by various affective manifestations.

Interoceptive awareness is the ability to perceive one’s own heartbeat, which may be relatively easily quantified using mental tracking procedures. In this paradigm, participants are asked to count their heartbeats in defined time intervals, with heartbeat perception indicated by the difference between the number of counted heartbeats and the number of actual heartbeats assessed via electrocardiography (ECG).

Fibromyalgia syndrome (FMS) is a form of fibromyalgia where pain and stiffness occurs in muscles, tendons, and ligaments throughout the body, accompanied by other generalized symptoms such as fatigue, sleep disruption or unrefreshing sleep, mood disorder, and cognitive difficulties such as poor memory or mental “fogginess.” Even though the cause underlying FMS is not known, this condition mainly affects middle-aged women.

The observation of diminished interoception in somatoform disorders encouraged researchers to investigate this issue in the context of FMS, as these syndromes exhibit considerable overlap with physical symptoms that cannot be sufficiently explained by concurrent organic disease.

In the study entitled “Diminished Interoceptive Awareness in Fibromyalgia Syndrome,” Gustavo A. Reyes del Paso from the Department of Psychology and colleagues, compared cardiac interoceptive awareness between 45 patients with a diagnosis of FMS and 31 healthy individuals. Interoceptive awareness was assessed using a heartbeat perception task. Cognitive performance, co-morbid psychiatric disorders, and medication use were assessed as possible confounding variables.

The results revealed that FMS patients exhibited a markedly reduced heartbeat perception compared to healthy individuals. The researchers also found an inverse relationship between interoceptive awareness and FMS symptom severity. Moreover, data revealed a significant reduction in cardiac interoceptive awareness in women with FMS. Poor access to bodily signals may limit patients’ ability to integrate these signals during emotional processing, which may inhibit optimal emotional self-regulation. Based on the results, the researchers indicated that “further research seems worthwhile to explore the precise role of poor interoception in the pathogenetic mechanisms of FMS, and to evaluate the utility of training in interoceptive awareness in the context of FMS treatment.”