Transcranial electrical stimulation devices
Transcranial electrical stimulation (tES) devices apply electrical waveforms through electrodes placed on the scalp to modulate brain function. This chapter describes the principles, types, and components of tES devices as well as practical considerations for their use. All tES devices include a waveform generator, electrodes, and an adhesive or headgear to position the electrodes. tES dose is defined by the size and position of electrodes, and the waveform, duration, and intensity of the current. Many sub-classes of tES are named based on dose. This chapter focuses on low-intensity tES, which includes transcranial direct current stimulation (tDCS), transcranial alternating current stimulation (tACS), and transcranial pulsed current stimulation (tPCS). tES electrode types are reviewed, including electrolyte-soaked sponge, adhesive hydrogel, high-definition, hand-held solid metal, free paste on electrode, and dry. Computational models support device design and individual targeting. The tolerability of tES is protocol specific, and medical-grade devices minimize risk.
