Investigation of Pain Modulation Phenotypes in Female Patients With Fibromyalgia

Investigation of Pain Modulation Phenotypes in Female Patients With Fibromyalgia

Fibromyalgia is characterized by altered pain processing, including impaired descending pain inhibition and central sensitization. While both mechanisms have been independently associated with disease severity, their interrelationship remains unclear. This cross-sectional study aims to investigate whether central sensitization symptoms mediate the relationship between conditioned pain modulation and fibromyalgia impact.

Fibromyalgia is characterized by altered pain processing mechanisms, including impaired descending pain inhibition and central sensitization. Although both mechanisms have been independently associated with symptom severity and functional impairment, their interrelationship and relative contributions to disease impact are not fully understood.

This study aims to examine the associations between conditioned pain modulation, central sensitization symptoms, and fibromyalgia impact. In particular, the study evaluates whether central sensitization symptoms act as a mediator in the relationship between impaired pain modulation and clinical disease burden. Participants with fibromyalgia are assessed using standardized clinical and psychological measures, including the Fibromyalgia Impact Questionnaire, Central Sensitization Inventory, and Hospital Anxiety and Depression Scale. Quantitative sensory testing is performed to evaluate conditioned pain modulation, pressure pain threshold, and temporal summation.Statistical analyses are conducted to explore bivariate associations and to identify independent predictors of fibromyalgia impact. A mediation framework is applied to assess whether central sensitization symptoms explain the relationship between pain modulation and clinical outcomes.

Inclusion Criteria:

1. Having received a diagnosis of fibromyalgia according to the 2016 ACR diagnostic criteria
2. Female patients aged 18-65
3. Being literate
4. Having signed the informed consent form upon agreeing to participate in the study

Exclusion Criteria:

1. Being under 18 or over 65 years of age
2. Having any condition that may lower the pain threshold or cause chronic pain (Rheumatoid Arthritis, Ankylosing Spondylitis, systemic inflammatory diseases, malignancies, etc.)
3. Any neurological condition (stroke, traumatic brain injury, multiple sclerosis, Parkinson's disease, central nervous system malignancies…)
4. Peripheral artery disease
5. Severe cardiopulmonary insufficiency (stage 3-4)
6. Uncontrolled systemic diseases such as hypertension and diabetes
7. Presence of an active infection
8. Pregnancy
9. Presence of cognitive impairment, hearing loss, or communication difficulties that would prevent understanding of questionnaires and protocols