Cerebral hemodynamics after transcranial direct current stimulation (tDCS) in patients with consequences of traumatic brain injury

Abstract

In recent years, hopes for better treatment of traumatic brain injury (TBI) have focused on non-pharmacologic transcranial electrical brain stimulation; however, studies of perfusion changes after stimulation are few and contradictory. Therefore, the aim of this study was to assess cerebral perfusion after high-definition transcranial direct current stimulation (HD-tDCS) in patients with posttraumatic encephalopathy (PTE). Methods. Twenty patients with PTE (16 men and 4 women, aged 35.5 ± 14.8 years) underwent perfusion computed tomography (PCT), followed by anodal HD-tDCS and post-stimulation tomography at 21 days after TBI. The Westermark perfusion maps were constructed and quantitative perfusion parameters calculated. Significance was preset to P < 0.05. Results. Qualitative analysis revealed that all patients had areas with reduced cerebral blood flow (CBF) and increased average mean transit time (MTT). HD-tDCS was accompanied by a significant decrease in the number of zones of both hypoperfusion and ischemia (p < 0.05). Quantitative analysis showed that, in all patients, HD-tDCS caused a significant increase in CBF (p < 0.001), cerebral blood volume (CBV) (p < 0.01) and MTT shortening (p < 0.05) in the frontotemporal region on the anode side. In the basal ganglia, a significant increase in CBF was found only in the five patients in whom this was initially reduced (p < 0.01) and only with an anode placed on the same side. Conclusions. In patients with complications due to PTE TBI, HD-tDCS causes a significant increase in CBV, CBF and a decrease in the average MTT, suggesting better oxygen delivery to tissue.