Mild Traumatic Brain Injury Assessment Based on EEG and MEG Analysis

Mild traumatic brain injury (mTBI) is difficult to diagnose because patients typically lack external injuries and pathological findings in conventional imaging. The main objective of this study has been the development of reliable biomarkers for mTBI. We compared brain activation profiles in 13 mTBI patients and 9 orthopedic controls using resting-state and evoked activity obtained with Electro- (EEG) and Magneto-encephalography (MEG). First, statistical analysis, spectral characteristics, and independent component topography were used to eliminate artifacts and then, the average power spectral density of each subject’s cortical sources was used to compare the two groups. We further investigated whether functional brain connectivity could assess recovery in mTBI patients using recordings obtained at three different visits using the Stroop and n-back working memory tasks. We analyzed evoked response amplitude and latency, sensor level connectivity, signal entropy, connectivity strength and directionality, as well as the local and global topological properties of the resulting brain networks. The ANOVA/MANOVA models included group, visit, experimental condition, and their interactions as fixed effects. Overall, mTBI patients exhibited statistically significant overactivation. In particular, controls showed significantly stronger connections between the two hemispheres, whereas mTBI patients had significantly stronger connectivity within the right hemisphere. Activity across repeat sessions did not show any significant differences within each group. These findings suggest that resting-state EEG/MEG activation networks can be used as biomarkers that can help detect mTBI and assess the efficacy of intervention. Furthermore, the lack of significant differences across the three recording sessions indicates that mTBI patients improve slowly, confirming independent reports that mTBI deficits may persist for years.Electrical and Computer Engineering, Department o