Cognitive dysfunction is one of the common clinical symptoms in multiple sclerosis (MS), but there is no effective treatment for it.

The aim of this study was to evaluate the effect of rivastigmine in treating memory and cognitive dysfunction in MS.

A single-center double-blind placebo-controlled randomized clinical trial conducted from October 2005 to February 2007. Sixty definite MS patients with cognitive impairment age 16 to 54 years were randomly allocated to receive a 12-week treatment course of either rivastigmine (1.5 mg once a day increment over 4 weeks to 3 mg twice daily) or placebo. Response to treatment was assessed by the Wechsler Memory Scale (WMS) at baseline and 12 weeks after start of therapy.

A slight, but significant memory improvement occurred in both groups. Of the 30 patients treated with rivastigmine, the mean (SD) WMS general memory score increased from 60.3 (4.2) at baseline to 64.9 (5.3) at the end of study period (P<0.001). Correspondingly, in the 30 patients treated with placebo, the mean (SD) WMS general memory score increased from 60.5 (4.9) to 64.5 (3.7) (P < 0.001). The average WMS general memory score at the end of trial did not changed between rivastigmine and placebo group (mean difference, 0.4; 95% CI, -2.0, 2.8).

No significant differences were seen between rivastigmine and placebo on the mean (SD) WMS general memory score. A larger multicenter study of rivastigmine in MS is warranted in order to more definitely assess the efficacy of this intervention.