Improvement of neuropsychological function in cognitively impaired multiple sclerosis patients treated with natalizumab: a preliminary study.

Treatment with natalizumab has been shown to reduce physical disability in people with multiple sclerosis (MS). However, its effect on neuropsychological dysfunction is not well understood. A single-center, open-label, retrospective study was conducted to evaluate the effect of natalizumab treatment on neuropsychological function in individuals with relapsing-remitting multiple sclerosis (RRMS) who had a measurable neuropsychological deficit prior to natalizumab treatment. A total of 40 MS patients (mean age, 48.5 years; 77.5% female) were evaluated on a neuropsychological battery of nine tests designed for MS patients before and after 6 or more months of treatment with natalizumab. Posttreatment neuropsychological testing results were compared to baseline results. The mean baseline Neuropsychological Impairment Index was 0.49, which improved to 0.41 after treatment (P = .0002) as analyzed using the Wilcoxon signed rank test. The mean Beck Depression Inventory-II (BDI-II) score improved by 2.45 points (P = .001). The mean Expanded Disability Status Scale (EDSS) score improved by 0.30 (P = .02). A total of 52.5% of patients showed neuropsychological improvement, while 30.0% showed no change and 17.5% had worsening. Magnetic resonance imaging showed no changes. The specific prior disease-modifying therapy had no influence on the results for natalizumab effect. The results of this study show that natalizumab can stabilize or improve neuropsychological function in RRMS patients. The improvement was consistent with, but apparently independent of, improvement in depression and physical disability.