Application of Noninvasive Brain Stimulation for Sleep Quality Enhancement and Cognitive Improvement.

Sleep is a fundamental process for maintaining our physical and mental health by adjusting brain homeostasis and repairing axons to refresh memories. Due to its essentiality, sleep disorders and insufficiency can cause both physiological and behavioral risks. This report diverges from traditional medical treatments and focuses mainly on physiotherapy-based neuroregulatory techniques for sleep treatment. Noninvasive brain stimulation (NiBS) techniques have been developed to enhance patients' sleep and memory, including transcranial electrical stimulation (tES), transcranial magnetic stimulation (TMS), closed-loop stimulation, and Slow-wave sleep (SWS) brain-wave music. These techniques not only facilitate sleep but also improve and manipulate patients' cognitive performance in areas such as addiction, post-traumatic stress disorder (PTSD), and Alzheimer's Disease (AD). However, brain stimulation during sleep has not yet been widely applied due to inconvenience of the large machines for long-term usage. Future research and engineering designs should focus on developing portable devices to restore sleep quality and cognitive performance. Insomnia can have multiple and interactive causes, including environmental, psychological, and physiological factors. Thus, case-by-case analyses are required, and neuroregulatory techniques play a supportive role in assisting sleep. To cure sleep problems completely, a combination of psychotherapy, medical treatments, and environmental adjustments may be necessary. There are still many puzzles to be solved in the study of sleep problems, and neurostimulation therapy provides new ideas for solving sleep problems and studying sleep behavior.