FMRI and EEG Reactions to Hand Motor Tasks in Patients with Mild Traumatic Brain Injury: Left-Hemispheric Sensitivity to Trauma

Background: Mild traumatic brain injury (mTBI) is one of the most common forms of cerebral pathology in young people and disorders involve dysfunctions in cognitive and motor spheres. We would like to examine the structural and functional alterations of the brain in patients with mTBI while performing hand movements. Methods: Twenty healthy right-handed subjects (age 25.1 ± 3.9) and 10 patients (age 27.9 ± 7.3) with mTBI without hemiparesis participated in the study using functional magnetic resonance imaging (fMRI) and electroencephalography (EEG). FMRI and EEG reactions were analysed during right- and left-hand movements. Results: It was shown that fMRI reactive changes have a larger inter-individual variability of activation during left-hand movements in comparison with right-hand ones in healthy subjects. The TBI patients demonstrated an increase of a diffuse component of fMRI reactive changes compared to healthy people. A greater number of the brain structures was involved, mainly at the subcortical level, mostly in the left hemisphere during right-hand movement. EEG study demonstrated coherence changes for the slow (delta) frequency bands in the left hemisphere, while performing both hand movements. In healthy persons, EEG coherence changes were observed in the fast (alhpa2) frequency band predominantly in contralateral hemispheres, while performing hand movements. Conclusion: So, fMRI and EEG studies revealed the most expressed pathological reactive changes in the left hemisphere and the brain cortical structures during right-hand movements in patients after mTBI. These data allowed us to propose that the younger brain structures were the most sensitive to mTBI.