Using sound that matches a person’s particular brain activity during sleep may be able to enhance that individual’s quality of deep sleep, and as a result, benefit metabolism and cognition, according to new research by a graduate student at Northwestern Medicine.
“Sleep deprivation, particularly of deep sleep, has been linked to poor cardio-metabolic functioning as well as problems in cognition,” said Nelly Papalambros, a third-year graduate student at Northwestern University’s Interdepartmental Neuroscience Ph.D. Program.
“There have been attempts at improving deep sleep with moderate success, but these approaches many times have unwanted side effects.”
The sound stimulation is personalized through an algorithm developed by Giovanni Santostasi, Ph.D. The algorithm reads a person’s specific EEG frequencies, or brain activity, and matches the bursts of sound during certain phases of slow wave sleep. The sound is pink noise, much like soft static or humming.
“The algorithm is unique because it can be customized to a specific person, older people have less slow wave sleep and the amplitude of their slow waves is smaller, so it allows you to hone in on that specific person for optimal stimulation,” Papalambros said.
For the study, patients with elevated risk of cardiovascular disease stayed overnight at an inpatient sleep research clinic to get a baseline measure of their physiological data, including insulin, blood glucose, hormone, and inflammation levels and information regarding their sleep patterns.
“We are seeing if the sound stimulation has acute effects on their health, but I think this is something that people could need to use over weeks or months to see any long lasting change. The hope is that this is an intervention for people with metabolic problems,” Papalambros said.
Spectral analysis was used to measure delta waves, which occur during deep sleep. Papalambros took note of any changes in the power of the waves with and without sound stimulation. The findings showed that in young people, sound does enhance deep sleep, and it may also have a positive effect on older adults.
Papalambros also studied whether enhancing deep sleep might improve cognition or memory. Before and after participants fell asleep, they were given a word pair test. Similar to the metabolism study, participants came into the clinic for nights with and without sound stimulation.
“Instead of extending the amount of sleep you get, these studies are more about the quality of sleep you get. If we can enhance sleep then hopefully we can improve metabolic function and cognition,” Papalambros said.
“Sound is non-invasive and, in theory, this method could be used as a clinical method or even adapted to a smart phone.”
Source: Northwestern Medicine