Electrosleep therapy

Electrosleep therapy, also referred to as Cranial Electrotherapy Stimulation (CES), is the application of electrical stimulation to a subject, typically in the form of pulsating direct current at low amplitude applied via electrode to the scalp or eyelids, for the intended purpose of inducing sleep or a hypnotic state.

Reading

• Solomon, Cyril (13 Jan. 1963), "The Russians' New Sleep Machine", This Week: 5-6, 8 
• Helvey, T. C. (1964), "Electronic Sleep Control of Astronauts", The Space Congress Proceedings: Where Are We Going In Space?, https://commons.erau.edu/cgi/viewcontent.cgi?article=3255&context=space-congress-proceedings  — "Astronautic mission profiles require for the crew, various sleep-wakefulness cycles which are quite different from the normal diurnal rhythm. It has been found that there are means by which certain levels of sleep can be induced electronically without undesirable side effects. The paper describes the efforts made so far in the international scientific community and also the results of his own experiments."
• Tad T., Brunye, et. al. (Feb. 2021), "A Critical Review of Cranial Electrotherapy Stimulation for Neuromodulation in Clinical and Non-Clinical Samples", Frontiers in Human Neuroscience, https://www.frontiersin.org/articles/10.3389/fnhum.2021.625321/full 

Devices

• Somniatron (Soviet Union)
• Electrosone
• Neurotone 101 (NeuroSystems, Inc. of Garland, Texas)
• Transcranial Electrostimulator