The purpose of our study was to assess the dynamics of local cerebral oxygenation (LCO) by near-infrared spectroscopy (NIRS) during transcranial direct current stimulation (tDCS) in the acute stage of mild traumatic brain injury (mTBI). Fifty-seven mTBI patients (18 women and 39 men, 35 ± 11.7 years old, GCS 13.7 ± 0.7) were treated by tDCS at 3-5 days after head injury. Stimulation parameters were: 1 mA, 9 V, duration-20 min. A cerebral oximeter was used to assess LCO-values in the frontotemporal lobes. Anodal and cathodal LCO values were compared before tDCS and every 2 min until the tDCS end. Significance was preset to p < 0.05. Results: A significant decrease in LCO values on the anodal side was observed at the 8th to 12th minutes of stimulation, compared to the cathodal side (at 8th minute - p = 0.011; at 12th minute - p < 0.00000001) and compared to LCO values before tDCS (p < 0.00001). The LCO on the cathodal side was not significantly different during the whole tDCS. At the end of the procedure, the interhemispheric LCO differences were not statistically significant (p = 0.757). Conclusions: Transcranial DCS in 3-5 days of mTBI leads to a significant decrease in the LCO value on the anodal side between 8 and 12 min and subsequent recovery to baseline values by the end of the procedure.
Keywords: Local cerebral oxygenation; Mild traumatic brain injury; Neurovascular coupling; Transcranial direct current stimulation.
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