Exploring the True Potential of the Spanish Central Sensitization Inventory: Factorial Structure, Convergent and Concurrent Validity

Background: This study aimed to explore the true potential of the Spanish Version of the Central Sensitization Inventory (CSI) in a sample of 262 chronic pain patients. Methods: We employed Confirmatory Factor Analysis to evaluate the fit of the data to the factorial solutions most commonly proposed in previous literature. Loadings of items covering the psychological manifestations of central sensitization, in comparison to other manifestations of this phenomenon, were examined. Convergence with psychological measurements was analyzed. Concurrent validity was examined by estimating the wind-up ratio (WUR) values from temporal summation of pain to repetitive pinprick stimulation in a subsample of 87 patients. Results: A bifactor model with a general factor and four orthogonal factors was the best solution. Loadings on the general factor of items examining the psychological concomitants of central sensitization were significantly higher than those of the items examining physiological symptoms. Conclusions: Our results indicate that this instrument may be more appropriate to assess aspects associated to cognitive-emotional sensitization or hypervigilance in patients with chronic pain rather than physiological alterations related to sensitization.