MIT researchers reported on Sept. 9, 2026, that short bursts of gentle pink noise delivered during sleep strengthened slow electrical waves in the brain, which in turn enlarged the waves of cerebrospinal fluid (CSF) that help clear waste. The study, published in Science Translational Medicine, tested 14 healthy volunteers. The bursts lasted 50 milliseconds and were timed to peaks in the participants' slow waves, which appear only during non-REM sleep.

Because the magnetic fields used for fMRI interfere with EEG signals, the team developed rapid signal processing and an algorithm to predict when slow-wave peaks would occur. The work was led by senior author Laura Lewis of MIT, with Joshua Levitt as lead author.

The researchers said they now hope to study whether enhanced CSF flow could support more restorative sleep, particularly for people with insomnia, and whether it might help in Alzheimer's and other diseases involving harmful protein buildup. They described these as future research directions, not established clinical benefits. Levitt has started a company that hopes to develop a home device such as a headband.