Cognitive functions can be assessed and followed up over a period of time with cognitive evoked potentials (CEP) P300� In this context, brainstem auditory evoked potentials (BAEP) are most commonly used, but visual evoked potentials (VEP) are utilized as well� The research in this area has demonstrated that these techniques could be used as a supplemental method in diagnostics of numerous diseases such as Alzheimer's disease, mild cognitive impairment, vascular dementia, epilepsy, craniocerebral trauma, Parkinson's disease, multiple sclerosis, and other degenerative diseases� In addition, P300 can also be used as an auxiliary method in the diagnostics of mental disorders conditions such as schizophrenia, panic disorders, narcotic drug addiction, nicotinism, alcoholism, etc� The method assists in monitoring the course of diseases leading to encephalopathy, such as liver and kidney damage and grave anaemia� The advantages of P300 testing are easy application, non-invasiveness, and an unlimited number of potential applications� Moreover, the results obtained with this method are measurable and can be compared�