Papalambros and her team have learned that hearing pink noise (described here: https://en.wikipedia.org/wiki/Pink_noise) while sleeping can enhance sleep quality and memory performance the day after the pink noise is heard among older individuals. People 60 to 84 years old participated in the Papalambros lead study and the pink noise was coordinated with sleeping brain rhythms. Zhou, Liu, Li, Ma, Zhang, and Fang (2012) reported, more generally, that “steady pink noise has significant effect on reducing brain wave complexity and inducing more stable sleep time to improve sleep quality of individuals.”
Nelly Papalambros, Giovanni Santostasi, Roneil Malkani, Rosemary Braun, Sandra Weintraub, Ken Paller, and Phyllis Zee. “Acoustic Enhancement of Sleep Slow Oscillations and Concomitant Memory Improvement in Older Adults.” Frontiers in Human Neuroscience, in press.
J. Zhou, D. Liu, J Ma, J. Zhang, and J. Fang. 2012. “Pink Noise: Effect on Complexity Synchronization of Brain Activity and Sleep Consolidation.” Journal of Theoretical Biology, vol. 306, pp. 68-72.