Regressive course of neurological signs and symptoms is an important factor of evaluating the clinical course and treatment efficacy of traumatic brain injury. This article presents changes evaluation of focal and brainstem symptoms in 200 patients with traumatic brain injury, and determines the association between these changes and the -675 4G/5G polymorphism in the PAI-1 gene. We have found a connection between 4G/4G and 4G/5G genotypes for the studied polymorphism and the changes of focal and brainstem symptoms in patients with traumatic brain injury. Thus, we have demonstrated that the clinical course of traumatic brain injury is influenced by the -675 4G/5G polymorphism in the PAI-1 gene.