Memory is our mind’s incredible faculty by which we retain information about everything that we come across in life. We often remember the souvenirs of the past that we want to hang on to as long as possible, revisiting times and places when we were happy and letting the power of our senses take us down memory lane. But memories go beyond our life story. Memory is an amalgamation of all kinds of experiences—all the information that comes our way and the conclusions we make with them.
We receive most of our memory input during our waking hours, but we need sleep for our brain to actually make sense of all of the new information taken in during the day. Particularly, deep sleep (also known as slow-wave sleep).
Sleep is a time of restful inactivity for the body, but the brain is actually working hard transferring all those imprints of our life during the day from the hippocampus to the cortex to be converted into long-term memories. Sleep consists of rapid eye movement sleep (REM) and non-rapid eye movement sleep (NREM), which alternate in cycles during an eight-hour period of rest. NREM sleep consists of three stages, with the third stage being the stage of deep sleep. It makes up about 20 percent of your total sleep time and is critical for maintaining a strong memory. (Fall asleep fast and sleep all night.)
Unfortunately, as you know, sleep quality declines with age, including the quality and amount of deep sleep. In fact, starting as early as middle age, deep sleep declines, contributing to age-related memory problems. Lifestyle adjustments and various sleep aids may or may not be helpful, and even if you’re getting your good night’s rest, you may not always get enough of that all-important deep sleep. A recent study published in Frontiers in Human Neuroscience has attempted to solve this problem using an innovative and promising technique.
Pink noise helps improve memory in older adults
Scientists suggest that listening to something called “pink noise”—a mix of high and low frequencies that sound more balanced than white noise—can help the elderly boost their deep sleep and improve recall.
The new study was based on previous research that found acoustic stimulation enhanced memory consolidation in young people. Researchers employed a novel approach, reading one’s brain waves in real time and delivering gentle sound stimulation precisely at the moment when neurons communicate during deep sleep. As a result, the neurons’ activity becomes better synchronized (meaning, memories are encoded more efficiently) and slow wave sleep is enhanced. (The secret behind unbelievable feats of mental ability?)
Study participants took a memory test at night and the morning after. The average recall improvement after acoustic pink-noise stimulation tripled compared to the sham stimulation during which participants didn’t hear any noise. The extent of slow-wave enhancement was related to the scale of memory improvement, demonstrating the significance of slow-wave sleep for memory.
Professor Phyllis Zee from Northwestern University in the U.S. described the pink-noise stimulation as “simple and safe non-medication approach that may help improve brain health” and “a potential tool for enhancing memory in older populations.” The results give hope for a viable home-based treatment option, although further research is required to assess the effects of sound stimulation night after night.