Transcranial direct current stimulation on hypertension: a systematic review and meta-analysis

Hypertension is a clinical condition that presents an enormous prevalence worldwide. Despite there being gold-standard treatments, several people frequently present sequelae and die. Transcranial direct current stimulation (tDCS) emerges as a cheap, easy-to-use, and portable intervention to modulate the central nervous system and control cardiovascular parameters.

To evaluate the tDCS effects on the hemodynamic and autonomic parameters of hypertensive people.

This systematic review included clinical trials published in databases that used tDCS as an intervention, isolated or associated, in hypertensive people to modulate the hemodynamic and autonomic parameters. We calculated the effect sizes, performed a meta-analysis, and evaluated the risk of bias in the studies. Three different researchers performed all the steps presented in the methods section.

Four studies suited the eligibility criteria of this review. Some studies showed that tDCS isolated after one session generated improvements in hemodynamic and autonomic parameters. Despite in meta-analysis, no statistical differences were detected between the groups, there was a tendency to reduce systolic (MD: -0.72 (CI: -1.54; 0.11; p = 0.06) and diastolic blood pressure (MD: -1.23; CI: -3.45; 0.99; p < 0.01), and root mean square of successive differences (MD: 0.73; CI: -0.30; 1.76; p < 0.01). There was no statistical difference after ten tDCS sessions. All the studies presented a low risk of bias.

After one session, isolated tDCS might be able to modulate hypertensive people's hemodynamic and autonomic parameters. The anodic stimulation over the primary motor cortex shows signs of being the best target to generate a response.