Characterizing Subjective Cognitive Impairment in Systemic Lupus Erythematosus Using the Perceived Deficits Questionnaire-20 and Associations with Objective Neuropsychological Testing

Objectives Cognitive impairment (CI) is one of the most frequent yet least understood neuropsychiatric manifestations of systemic lupus erythematosus (SLE), affecting up to 40% of patients. While the American College of Rheumatology Neuropsychological Battery (ACR-NB) remains the gold standard for objective assessment, it is time-intensive and does not capture the lived experience of patients with subjective CI or “brain fog.” The Perceived Deficits Questionnaire-20 (PDQ-20) measures self-reported cognitive difficulties, but its role in SLE is not well established. Our objective was to characterize patient-reported cognitive symptoms using the PDQ-20 and examine its relationship with objective CI measured by the ACR-NB. Methods We performed a cross-sectional study of 214 adult SLE patients from a single-center longitudinal cohort who completed both the PDQ-20 and ACR-NB. The PDQ-20 assesses 4 domains—attention/concentration, planning/organization, retrospective memory, and prospective memory—across 20 items scored 0–4 (higher = worse). Objective cognition was evaluated using a modified ACR-NB assessing 6 domains: manual motor speed, attention/processing speed, visuospatial construction, language, learning/memory, and executive function. CI was defined as impairment (z ≤ −1.5) in ≥2 domains. Spearman correlations examined construct validity between PDQ-20 items/domains and ACR-NB tests, while Wilcoxon rank-sum tests compared PDQ-20 scores between CI and non-CI groups. Results Participants were predominantly female (90%), with a mean age of 31 ± 17 years; 43% met criteria for objective CI. The mean PDQ-20 score was 31.1 ± 16.9 (out of 80), indicating moderate subjective impairment. The most frequently reported difficulties were “mind wandering,” “forgetting names,” “losing train of thought,” and “forgetting why one entered a room,” reflecting deficits in attention and working memory. The highest domain scores were observed in attention/concentration and planning/organization. Correlations between PDQ-20 and ACR-NB scores were generally weak. The strongest associations were between PDQ-20 items related to working memory (eg, Q17 “trouble holding phone numbers,” Q4 “trouble organizing”) and the ACR-NB Auditory Consonant Trigrams test (r ≈ −0.25 to −0.29). No significant difference in PDQ-20 total scores was observed between CI (33.4 ± 17.5) and non-CI (29.3 ± 15.9) groups (p = 0.15), nor were there differences between individual PDQ-20 items (Figure 1). Conclusion SLE patients frequently report cognitive challenges, particularly in attention and planning, which correlate only weakly with objective CI. The PDQ-20 captures everyday cognitive experiences not reflected by formal testing, highlighting the need to assess both subjective and objective cognition in SLE. Integrating patient-reported cognitive screening may enhance understanding, monitoring, and support for cognitive health in clinical practice.