3D-printable stimulation electrodes to improve precision, reproducibility, and reliability of transcranial electric current stimulation

Abstract

Objective

Transcranial electric stimulation (tES) refers to noninvasive neuromodulation techniques that apply a low-amplitude electric current through scalp electrodes to modulate brain activity. Conventional scalp electrodes are made of conductive rubber and are embedded in saline-soaked sponges, held in place using non-conductive rubber straps. Precisely positioning the electrodes at the desired location is challenging, and maintaining their position is equally difficult. In addition, as sponges are prone to drying out during prolonged use, they can compromise the electrode’s conductivity and therefore cause fluctuations in connectivity.

Methods

To tackle these limitations of conventional tES electrodes, we designed new 3D-printable gel-filled tES electrodes.

Results

We developed electrodes in various sizes ranging in radius from 12 mm to 30 mm to allow a wide variety of options regarding stimulation parameters and electrode montages. By integrating the electrodes into a 10–20-cap, they can be positioned precisely according to the 10–20 coordinate system and the cap holds them in place, even during significant movements.

Conclusions

Sharing our 3D-printable electrode designs as open-source can improve precision, reproducibility, and reliability of tES.

Significance

In this way, we aim to tackle the reliability and reproducibility issues in the tES field as they provide an accessible and reliable tool to apply tES in humans.