MIT researchers report that brief bursts of pink noise, synchronized with sleeping participants' brain activity, increased the amplitude of slow brain waves and cerebrospinal-fluid waves in 14 healthy volunteers.
According to MIT's September 9 announcement, the team used EEG to time 50-millisecond sounds and fMRI to monitor the fluid response. Cerebrospinal fluid surrounds the brain and spinal cord. The work appeared in Science Translational Medicine.
The distinction is timing. This experiment used measured brain activity to control the stimulus, rather than playing a continuous background recording.
The findings do not establish better sleep, improved memory, increased waste clearance or prevention of neurodegenerative disease. Those possible benefits require further investigation. Lead author Joshua Levitt has also started a company pursuing a device for home use, MIT reports.