Scientific Breakthroughs

New Study Shows Pink Noise Helps Adults Fall Into Deep Sleep, Helps Memory

New Study Shows Pink Noise Helps Adults Fall Into Deep Sleep, Helps Memory
PHOTOGRAPH: Sleep Foundation | Photo shows a woman sleeping.

A new study shows that the sound called “pink noise” can put adults into a deep sleep. In turn, deeper slumber can significantly help them form and retain memories.

Research has shown that a deep sleep enables people to form memories. As we age, we become more accustomed to lighter and intermittent sleep. Older people tend to get less slow-wave sleep and are at greater risk for memory impairment.

Previous studies point to a certain kind of sound called “pink noise” as helpful in improving the memories of young adults. The new study aimed to learn if the same effect would be enjoyed by the elderly. The findings have been published in Frontiers in Human Neuroscience.

Pink, in contrast to white noise, may be described as a soothing sound with high and low frequencies. The sound is not continuous like white noise, and is just noticeable enough to the brain without disrupting sleep. Prof. Phyllis Zee of Northwestern University Feinberg School of Medicine, lead author of the study, selects nature sounds like the rush of water as the nearest resemblance to the sound.

That same subtle noise was played into headphones by a team of researchers. The subjects were 13 adults who were 60 years of age or above. They went to bed wearing the headphones and an electrode cap.

Sleeping soundly may be a matter of sound stimulus

During the test, the sounds were synchronized with the sleeping persons’ slow-wave oscillations. These oscillations – around one per second – occur during a deep sleep. When people are awake, the oscillations come faster, at about ten per second.

It was when those slow waves began to happen that the noise was transmitted into the headphones. The result is that the slow waves increased after the participants were subjected to the sound.

This means that their periods of deep slumber had become longer, which is good for optimum body functioning. Furthermore, the subjects got higher scores – three times better – in memory tests the morning after their sleep.

The study needs to be continued on a greater scale. For one thing, it has to be determined if longer exposure to the sound would have similar or different effects.

The technology is there; it just needs to be refined. As it is, the researchers seem to have found a way to stimulate the slow waves that correspond with heavy slumber. Memory is also tied up with that sound stimulus.

Northwestern has begun to obtain a patent for the technology. One of the study’s authors has even co-started a company intent on marketing it. Ultimately, the plan is to put that innovation to home use, by means of an affordable device in the market.


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