Clinical and diagnostic features of repeated mild traumatic brain injuries

Abstract

Repeated mild traumatic brain injury (TBI) leads to new changes and exacerbates the existing ones caused by the primary trauma. The pathogenetic mechanisms of repeated TBI are the result of traumatic effects and their cumulation. They cause various morphological and functional changes in the brain. Objective — to improve the diagnosis of pathological changes in patients with repeated mild traumatic brain injury. Materials and methods. The study involved 199 patients with a history of repeated mild TBI. Men predominated among them — 158 (79.40 %). There were 80 (40.20 %) patients of youthful age (17—24 years), 78 (39.20 %) of young age (25—44 years), and 41 (20.60 %) of middle-aged (45—60 years). The number of repeated TBIs per patient ranged from two to five. All patients were examined in the remote period of TBI. The control group consisted of 30 people aged 18 to 50 years (mean age — (33.11 ± 3.09) years) who had no history of TBI. Cognitive impairment (CI) was assessed by neuropsychological examination using the Mini-Mental State Examination (MMSE), the Frontal Area Battery (FAB), and the clock drawing test. Methods of neuropsychological analysis, neuroimaging and neurophysiological methods were used. The data of clinical and neurological examinations and studies of cognitive functions were analyzed, structural changes of the brain and cerebrospinal tract were established on the basis of neuroimaging studies of the brain, and the peculiarities of cerebral hemodynamics in patients with mild repeated TBI were determined. The characteristics of neurophysiological changes in patients are given based on the study of the features of electroencephalographic changes and the study of cognitive evoked potentials of the brain. The immune status was evaluated in patients who had repeated mild TBI. Results. Repeated TBI in our study was observed in the form of mild concussions and brain contusions. Their number in one patient ranged from 1 to 5. Clinical manifestations of repeated mild TBI had peculiarities: cephalalgic, cerebral and cerebrospinal hypertensive syndrome, cognitive impairment, diffuse neurological symptoms, and pyramidal insufficiency prevailed in the clinical picture. Only in the main group were cases of a combination of three to eight neurological syndromes detected. A decrease in cognitive function was found in patients with repeated mild TBI compared to the control group according to neuropsychological testing. The analysis of cognitive evoked potentials revealed an increase in the latent period of the cognitive complex P300 in patients with repeated TBI compared with the control group, indicating a decrease in cognitive function. More frequent CP was detected in the main group. The use of modern neuroimaging methods revealed that patients with repeated TBI had increased width of the lateral ventricles on both sides, ventricle III, and the cavity of the septum compared with the control group, as well as a higher frequency of expansion of the septum and convexity of the subarachnoid spaces. Patients with repeated mild TBI are characterised by an increase in blood flow velocity in the extracranial parts of the carotid basin and a decrease in velocity in the vessels of the vertebrobasilar basin with a change in vascular resistance, in the segments of the intracranial part of the carotid basin — a decrease in blood flow velocity without a change in vascular resistance. Disorders of venous cerebral circulation (increased velocity in the internal jugular vein and Rosenthal veins) were recorded in the majority of the main group. According to the data of the CEG, in patients with repeated TBI against the background of diffuse changes in brain bioelectrical activity, focal changes in the left hemisphere of the brain are more common. Dominant arrhythmia was recorded in 97.78 % of patients in the main group. The amplitude of arrhythmia in patients with repeated TBI is lower compared to the control group, and the frequency of arrhythmic oscillations is higher. Conclusions. The use of clinical and diagnostic control allows to prevent the development of damage and obtain objective information about the state of the brain and its structures.