Posted on Apr 27, 2017, 6 a.m.
Gentle sound stimulation synchronized to the rhythm of brain waves significantly enhances deep sleep in older adults and improves their ability to recall words.
Researchers at Northwestern University have determined that soft sound stimulation synced up with the rhythm of brain waves induces an improved deep sleep in older individuals. Such stimulation even boosts those adults' ability to recall specific words. An example of such gentle audio stimulation is a rushing waterfall. The study details were recently published in the journal Frontiers in Human Neuroscience.
The Importance of Deep Sleep
Deep sleep is critical for the consolidation of memories. However, when one reaches middle age, deep sleep typically decreases. Scientists believe this is part of the reason why memory loss occurs throughout the aging process. Sound stimulation might be the solution to combat such memory loss.
When deep sleep occurs, each brain wave is reduced to one per second. This is quite the slow rate compared to the 10 oscillations that occur every second when one is awake. The study's co-author, Giovanni Santostasi, created an algorithm that transmits audio during the rising part of slow wave oscillations. Such stimulation boosts the synchronization of neuron activity.
The study involved 13 individuals age 60 or older. They were recruited from Northwestern's Cognitive Neurology and Alzheimer's Disease Center. The study keyed in on older individuals as they have plenty to gain in terms of memory recall from improved deep sleep.
The study made use of a breakthrough audio system that improved the effectiveness of stimulation in older individuals. The study's new approach reads one's brain waves as they occur. It locks in the subtle audio stimulation when a specific moment of neuron communication occurs during deep sleep.
The participants were provided with a single night of acoustic stimulation and a night of false stimulation. The false stimulation was the same as the acoustic version yet the subjects did not hear noise while sleeping. The participants were given a memory test the night of their acoustic and sham stimulation sessions. They completed another memory test the next morning.
Memory recall ability following the false stimulation improved by a couple percentage points. Those subjected to pink noise the night before enjoyed vastly superior memory recall. The improvement was about three times that of those exposed to the sham stimulation. The magnitude of the slow wave sleep enhancement played a part in the level of memory improvement. This suggests slow wave sleep is beneficial for memory even as one reaches his golden years.
A Non-medication Approach to Improving Sleep and Memory
The beauty of audio stimulation is that it does not require expensive medication that often causes nasty side effects. This “pink noise” as it is often referred to, is a simple and completely safe means of boosting brain health.
Nelly A. Papalambros et al. Acoustic Enhancement of Sleep Slow Oscillations and Concomitant Memory Improvement in Older Adults, Frontiers in Human Neuroscience (2017). DOI: 10.3389/fnhum.2017.00109