Cognitive Function in Patients With Complex Regional Pain Syndrome: No Clear Impairment Found in a Select Patient Sample

Abstract

Background: Given the impact of chronic pain on cognition, CRPS may affect specific cognitive functions. However, cognitive functioning is rarely assessed in CRPS, and previous studies have examined only limited domains. As a result, it remains unclear which cognitive functions are affected and whether impairments are CRPS-specific. This study comprehensively evaluates cognition in CRPS and compares it to carpal tunnel syndrome (CTS) to determine whether cognitive dysfunction is specific to CRPS. Methods: All patients underwent a standardised cognitive assessment consisting of ten tests, evaluating the domains of memory, concentration, executive functioning, social cognition and performance validity. Standardised z-scores and proportion of low-performing patients (< −1.5 SD from age-, sex- and education adjusted normative data) were examined. Both patient groups were compared with each other and the expected population proportion. Results: Sixty-four patients (n = 39 CRPS and n = 25 CTS) with a mean age of 52.5 (range 20–81) were included. Compared with patients with CTS, patients with CRPS had significantly higher pain scores 24 h before and during the visit (p < 0.001). All cognitive test results were similar between the two groups. Z-scores of both groups were comparable or better than the population norm. Furthermore, proportions of patients with Z-scores below −1.5 SD were similar or better than expected. Conclusions: Our results consistently showed no cognitive impairment in either patient group. Both groups met or exceeded population norms on all tests. However, despite our clear results, attention should be paid to factors affecting cognition, like depression, anxiety and stress. Significance Statement: This study explores the underexamined cognitive dysfunction in Complex Regional Pain Syndrome (CRPS). Cognitive issues, often reported by CRPS patients, can add to the burden on daily life and quality of life (QoL) but are rarely assessed. By comparing CRPS with CTS, this research examines whether cognitive impairments are specific to CRPS. Identifying these issues may lead to targeted therapies addressing both pain and cognitive challenges, ultimately improving patient outcomes and QoL.