'Pink noise' can help old people sleep their way to better memory

Washington D.C.: You may want to listen to pink noise, described as a waterfall-like sound, during bedtime as a recent study has suggested that doing so can improve memory.

The study is published in Frontiers in Human Neuroscience. Gentle sound stimulation synchronized to the rhythm of brain waves significantly enhanced deep sleep in older adults and improved their ability to recall words, reported a new Northwestern Medicine study.

"This is an innovative, simple and safe non-medication approach that may help improve brain health," said senior author Phyllis Zee. "This is a potential tool for enhancing memory in older populations and attenuating normal age-related memory decline."

In the study, 13 participants 60 and older received one night of acoustic stimulation and one night of sham stimulation. The sham stimulation procedure was identical to the acoustic one, but participants did not hear any noise during sleep. For both the sham and acoustic stimulation sessions, the individuals took a memory test at night and again the next morning. Recall ability after the sham stimulation generally improved on the morning test by a few percent. However, the average improvement was three times larger after pink-noise stimulation.

The degree of slow wave sleep enhancement was related to the degree of memory improvement, suggesting slow wave sleep remains important for memory, even in old age.

Although the Northwestern scientists have not yet studied the effect of repeated nights of stimulation, this method could be a viable intervention for longer-term use in the home, Zee said.