Slow Wave Sleep Brainwave Soft Waves

https://www.sciencedirect.com/science/article/pii/S1389945725004307?fr=RR-2&ref=pdf_download&rr=a13f6e829daeae19 Listening to brainwave entrainment sound modulations while sleeping can improve sleep quality and quantity. Isochronic tones, vibration encoding, strobe flicker encoding, and other effects are presented randomly in the delta 5- 4 Hz range to mimic one's own sleeping brainwaves. Technically, this is too slow for the brain to detect a pattern and initiate the frequency-following response. However, this research and earlier research conducted at Northwestern University in Chicago show an increase in the amplitudes of not only delta frequencies but also alpha and beta frequencies present during REM sleep.