Study: Sound waves enhance deep sleep, memory

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Gentle sound stimulation that synchronizes to the rhythm of brain waves could significantly enhance deep sleep in older adults and improve their ability to recall words, a new study of the Northwestern Medicine shows.

In the study, 13 participants aged 60 and older from the Cognitive Neurology and Alzheimer's Disease Center at Northwestern University (NU) Feinberg School of Medicine 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.

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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, a form of noise similar to the sounds that human ears can pick up the best.

The study has used a new approach to read an individual's brain waves in real time and lock in the gentle sound stimulation during a precise moment of neuron communication during deep sleep, which varies for each person.

Though NU researchers have not yet studied the effect of repeated nights of stimulation, this method could provide a viable intervention for longer-term use in the home, said senior author Dr. Phyllis Zee, professor of neurology at Northwestern University Feinberg School of Medicine and a Northwestern Medicine sleep specialist.

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

While previous research only proved that acoustic simulation played during deep sleep could improve memory consolidation in young people, the new study has targeted older individuals.

NU researchers are also testing the acoustic stimulation in overnight sleep studies on patients with memory complaints. Previous studies demonstrated a possible link between the sleep and memory impairments for adults with mild cognitive impairment.

The study has been published in Frontiers in Human Neuroscience. And NU has a patent pending for the technology.

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Source(s): Xinhua News Agency