Objective. To assess the complexity of the mental state in terms of court trial participation of a person accused of communist crimes 50 years ago. Method. A description of the need for multiple tests at an interval of 16 months in connection with verifying the ability to participate in the trial. Results. In the first opinion, team of experts put the diagnosis: characteristics of an organic brain syndrome in the form of mild dementia. In the second opinion, done after 16 months, experts recognised the developing process of a moderate dementia. Conclusions. In a 80-year old person for whom the opinion was issued, in over 16 months there has been a significant increase in the process of dementia, which eventually prevented participation in the trial.