Abstract
The aim was to evaluate the changes in brain tissue oxygenation, assessed by near-infrared spectroscopy (NIRS), during transcranial alternating current stimulation (tACS) in patients with mild and moderate traumatic brain injury (TBI). Nineteen patients with diffuse, blunt, non-severe TBI (mean age 32.7 ± 11.4 years; 4 women and 15 men; Glasgow Coma Score before tACS 14.1 ± 0.5) were treated by 10 Hz in-phase tACS applied for 30 minutes to the left and right lateral prefrontal cortex at 21 days after TBI. Regional cerebral tissue oxygen saturation (SctO(2)) in the frontal lobes was measured simultaneously by the cerebral oximeter. Significance was preset to P < 0.05. The SctO(2) values before tACS were not different between hemispheres ~65%. After 15 minutes of tACS, a significant (p < 0.05) decrease in regional SctO(2) was observed with the minimum at the eighth minute of 53.4 ± 3.2% and 53.4 ± 3.2% in the left and right hemispheres, respectively. At the end of the stimulation (30 minutes), the hemispheric differences in cerebral oxygen saturation became statistically insignificant again (p > 0.05). Therefore, tACS causes a significant decrease in SctO(2), probably, due to neuronal activation. Our data indicate that tACS may need to be supplemented with oxygen therapy. Further research is required.