New Book Chapter: Noninvasive Electrical Brain Stimulation of the Central Nervous System
Niranjan Khadka, Marom Bikson. Noninvasive Electrical Brain Stimulation of the Central Nervous System. 2022. Handbook of Neuroengineering. Springer. https://doi.org/10.1007/978-981-15-2848-4_59-1
Abstract
Noninvasive electrical brain stimulation of the central nervous system spans a broad range of devices and techniques that aim to change brain function with electrical current applied through electrodes on the surface of the body. The applications of such techniques span treatment of a wide range of neuropsychiatric disorders, healing of the nervous system after an injury, and experimental manipulations to study brain function. This chapter focuses on transcranial electrical stimulation (tES) which involves electrodes placed on the scalp with the goal of passing current through the skull and directly stimulate the cortex. tES itself is divided into subtechniques that are classified by the waveform applied and/or by the application of intended use. All tES devices share certain common features including a waveform generator and electrodes that are fully disposable or include a disposable component. The device applies the waveform to the electrodes through lead wires. tES “dose” is defined by the size and position of electrodes, and waveform includes the pattern, duration, and intensity of current. Versions of low-intensity tES include transcranial direct current stimulation (tDCS) and transcranial alternating current stimulation (tACS). Impedance measurement is largely used to monitor acceptability of electrode-skin properties. Computational FEM models of current flow support device design and programming by informing how to select dose to produce a given outcome. The evidence for tES use across varied clinical applications, spanning treatment of neuropsychiatric disorders and neurorehabilitation following injury, as well as a tool to change cognition and behavior in healthy individuals is developing.
