Help your grandparents sleep better with this..

Help your grandparents sleep better and improve memory, with gentle sound stimulation - such as rush of a waterfall - synchronised to the rhythm of brain waves, as it may significantly deepen sleep and triple memory scores to recall words in older adults, suggests a study.

According to researchers from Northwestern University in Evanston, US, pink noise synced to brain waves deepens sleep and triples memory scores in older adults aged 60 and above.

The study appeared in journal of Frontiers in Human Neuroscience.

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.

"This is an innovative, simple and safe non-medication approach that may help improve brain's health," said senior study author Dr. Phyllis Zee from Northwestern University's feinberg school of medicine.

"This is a potential tool for enhancing memory in older populations and attenuating normal age-related memory decline," Zee added.

They analysed 13 participants aged 60 and older, who received one night of acoustic stimulation - relating to sound and one night of sham stimulation - that is used in research to control for the placebo effect.

The sham stimulation procedure was identical to the acoustic one, but participants did not hear any noise during sleep.

For both the sessions, the participants took a memory test at night and again the next morning.

The results indicated that 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.

After the sound stimulation, the older participants' slow waves increased during sleep.