Researchers are continuing to explore the relationship between sleep and cognition in older adults. (For example, see here.) Recently, researchers examined one potential technology for improving the quality of older adults’ sleep: pink noise.
Of particular importance for memory and cognition is slow wave sleep, or deep sleep. Disruption or lack of slow wave sleep has been shown to interfere with the creation of new memories. Unfortunately, sleep in older adults tends to feature both reductions in the amounts of slow wave sleep and more frequent awakenings during the night. One way that was proposed to improve slow wave sleep was via acoustical stimulation, or playing certain patterns of sound to boost slow wave activity. In particular, researchers examined pulses of pink noise, which had shown some positive benefits for younger adults during naps. Pink noise (which can be heard here) sounds like static, but with decreasing levels of high frequency content. In this study, the pink noise was also timed to match the rhythm of participants’ slow wave sleep.
For this study, 13 participants spent two nights in a sleep lab, one in which pink noise was played when the participant entered slow wave sleep and another in which it was not. Electrophysiological recordings were taken while participants slept, and they were given a delayed recall memory test before and after each night’s sleep.
When the researchers compared participants’ memory performance when they received pink noise to when they did not, they found that the pink noise condition produced great improvements. These improvements were correlated with observed changes in the electrophysiological measurements taken while the participants slept. After pink noise, the average improvement was 27 percent, compared to only a 6 percent improvement on the night with no pink noise.
Although more research needs to be done, there is already a patent pending on the technology and the authors have founded a company to translate this research into an affordable device that can be used at home. In the meantime, this is a demonstration of the importance of doing as much as possible to get a good night’s sleep.
Papalambros NA, Santostasi G, Malkani RG, 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/full