Cognitive impairment, event-related potentials and immunological status in patients with systemic lupus erythematosus.

BACKGROUND

Cognitive impairment (CI) is a frequent problem in lupus patients, regardless of their overt neuropsychiatric (NP) involvement.

OBJECTIVES

The aim of our study was to test cognitive abilities in systemic lupus erythematosus (SLE) patients by means of neuropsychological testing and event-related potentials (ERPs), and to search for their cognitive abilities correlations with a wide range of auto-antibodies.

MATERIAL AND METHODS

A total of 37 SLE patients were subjected to a battery of neuropsychological tests, recommended by the American College of Rheumatology (ACR), and to ERPs. They were also tested for a wide range of auto-antibodies (anti-cardiolipin (aCL), anti-β2-glycoprotein I (anti-β2-GPI), lupus anticoagulant, anti-dsDNA, anti-nucleosome, anti-ribosomal P (anti-Rib-P), anti-ganglioside, anti-Ro/SS-A, and anti-La/SS-B.

RESULTS

Cognitive impairment was found in 35% of patients, mostly with NP SLE (NPSLE), and was associated with higher disease activity, measured by the SLE Disease Activity Index (SLEDAI), and with a longer duration of central nervous system (CNS) involvement. There were no differences in the immunological status between CI patients and those without cognitive decline, but some antibodies were correlated with worse results in certain neuropsychological tests (anti-dsDNA and worse results of Rey Complex Figure Test - RCFTc for copying and RCFTr for recall, and of verbal fluency test (VFT); aCL IgG and worse results in Digit Span (DS) and in RCFTc). Event-related potentials showed prolonged N200 and P300 latencies in SLE patients in comparison to controls, but no differences were found between SLE and NPSLE patients. Mean P300 latency was significantly longer in patients without anti-nucleosome antibodies.

CONCLUSIONS

Event-related potentials can be used as a complementary tool in assessing CI in SLE patients. The immunological status of patients with CI did not differ from that of patients without cognitive problems.