Agreement Between CSI and IASP Pain Classification in Chronic Cervical Myofascial Pain

This study aims to investigate how closely two approaches to assessing pain-related characteristics agree in adults with chronic cervical myofascial pain syndrome (chronic neck pain associated with painful muscle trigger points). The Central Sensitization Inventory (CSI) is a questionnaire that assesses symptoms associated with increased pain sensitivity. The International Association for the Study of Pain (IASP) has developed clinical criteria to identify nociplastic pain, a type of pain that cannot be fully explained by tissue damage or nerve injury. These approaches provide different types of information, and it is unclear how often they classify patients with chronic cervical myofascial pain in the same way. This observational, cross-sectional study will include 150 adults aged 18 years or older with chronic cervical myofascial pain syndrome. Participants will undergo a clinical assessment based on the IASP nociplastic pain criteria and complete the CSI, Neck Disability Index (NDI), and Revised Illness Perception Questionnaire (IPQ-R). Pain severity and relevant clinical information will also be recorded. The main objective is to determine the agreement between CSI classification using a cutoff score of 40 and IASP clinical classification of nociplastic pain. The study will also examine how often the two approaches produce different classifications and whether patients with matching or differing classifications report different emotional responses to their illness. All assessments will be completed during a single visit. No experimental treatments or additional invasive procedures will be performed.