Validation of the brief cognitive symptoms index in Sjögren syndrome

The Brief Cognitive Symptoms Inventory (BCSI) is a short, self-report scale designed to measure cognitive symptomatology in patients with rheumatic disease. To facilitate research and clinical practice, we tested the internal consistency and validity of the BCSI in patients with Sjögren syndrome (SS).

Patients who met the American-European Consensus Group criteria for SS and healthy controls completed a questionnaire assessing symptoms including cognitive complaints. We calculated Cronbach's alpha to assess internal consistency and Pearson correlation coefficients to test for association between BCSI, symptoms, and demographic variables. Total score distribution was analyzed to establish cutoff criteria for differentiation of case versus non-case. We compared neuropsychological outcomes of patients with SS above and below the threshold BCSI score to assess the association of cognitive symptoms with objective cognitive deficits.

Complete data were available on 144 patients with SS and 35 controls. Internal consistency of the BCSI was good. Scores were similar in all patient groups and patients reported more cognitive symptoms than controls (p < 0.0001). BCSI scores correlated moderately with pain, depression, anxiety, fatigue, and health quality. High scores for cognitive dysfunction were reported by 20% of the patients with SS and only 3% of controls. Patients with cognitive scores > 50 had more depression, fatigue, pain (effect size all > 1), and worse performance on multiple cognitive domains.

The BCSI should be a useful tool for the study of cognitive symptoms in SS. Both self-report and standardized tests should be considered in screening for cognitive disorders in SS.