Abstract
Cognitive impairment occurs in a high percentage in all forms of multiple sclerosis, regardless of physical disability. Slowing the speed of information processing is one of the most difficult and the most frequently mentioned, but impairment of memory, attention, executive functions are included also. Long latency event related potentials (ERP) are much more objective means of cognitive functioning evaluation. Different types of immunomodulatory therapies which are used for relapsing- remitting forms of multiple sclerosis may affect the results of ERP. ERP can evaluate subclinical changes and provide important information on the evolution of cognitive changes in patients with MS.