Delta power surge and alpha power decline in traumatic brain injury recovery: A quantitative EEG analysis of the CAPTAIN-rTMS trial.

Introduction: Traumatic brain injury (TBI) is a leading cause of disability and death. Both repetitive transcranial magnetic stimulation (rTMS) and Cerebrolysin (CRB) are promising therapies regulating neural plasticity. This study aimed to assess the changes in resting-state brain activity following CRB, rTMS, or combined CRB-rTMS therapy. Methods: This secondary analysis of the CAPTAIN-rTMS trial analyzed eyes-closed segments from EEG recordings at 30 days (baseline) and 180 days (after treatment) respectively. We computed relative power spectral densities for delta, theta, alpha and beta frequency bands, for the entire scalp and different regions. We conducted neuropsychological assessments and evaluated the correlations between resting-state relative power spectral density values and neuropsychological assessment performance. Results: We analyzed a total of 50 patients. For the entire scalp, we found statistically significant decreases in relative alpha power (p = 0.02) and significant increases in relative delta power (p = 0.02), further subgroup analysis showing differences between visits in the CRB + sham group (paired Cliff's δ = 0.6, p = 0.012 for Delta band, δ = 0.6, p = 0.064 for Alpha band). The differences were higher in the central (alpha p = 0.004, delta p = 0.002) and parietal (alpha p = 0.012, delta p = 0.03), and lower in the frontal (alpha p = 0.05, delta p = 0.026), temporal (alpha p = 0.065, delta p = 0.077), and occipital (alpha p = 0.064, delta p = 0.084) regions. Neuropsychological tests performance was negatively correlated with resting-state relative delta power, and positively correlated with alpha power. Conclusion: We found overall slowing of brain electrical activity during recovery after TBI, which was further influenced by rTMS and CRB treatment. Resting-state relative power spectral densities correlate with neuropsychological measurements.