Many individuals, particularly the elderly, are suffering from abnormal sleep. In particular, the deep sleep phases become shorter and deeper with age. Deep sleep is vital for the brain and memory recovery, and also has a positive influence on the cardiovascular system.
Researchers have shown that deep sleep, the so-called slow waves, can be improved by playing precisely timed sounds through earphones while sleeping. While this works well in the sleep laboratory under controlled conditions, there has thus far no at home solution that can be used longer than one night.
SleepLoop to the rescue
Researchers at ETH Zurich have developed a mobile device that can be used at home and aims to promote deep sleep through auditory brain stimulation.
This headband, which is then placed on during bedtime and worn throughout the night, is constantly measuring the brain activity of the person sleeping. This data is then monitored autonomously in real-time on the microchip using custom software. This helps to synchronize the neuronal cells and increase the slow waves. What makes the solution unique is that the person sleeping is not conciously aware of this sound during deep sleep.
The first clinical study
For the first time, researchers from ETH Zurich and University Hospital Zurich, led by Caroline Lustenberger, a group leader at the Neural Control of Movement Lab, conducted a clinical study with this device. The results have just been published in the journalCommunications Medicine.
Participants were required to operate independently from a home thanks to a sleepLoop technology, which was designed to even by users with limited technical experience. This was a very beneficial experience. We had a very little data loss and the participants rated the device as user-friendly.
The subjects nor the researchers were aware that the auditory signals were played every night for a total of four weeks, with the nighttime stimulation scheduled for two weeks and no stimulation for the next two weeks.
Auditory stimulation is indeed feasible
The results of 16 participants in the study demonstrate that it was effective to increase the slow waves through auditory signals during deep sleep. Despite their individual differences, some of the subjects were very responsive to the stimuli, while others responded very effectively or not at all.
According to Lustenberger, whether a person reacted to a stimulus did not imply their well-being during the day. Generally, some people responded well to the stimuli, and showed significant slow waves, although others showed no response, irrespective of their daily well-being.
These individual differences have been used by researchers to better predict how a given individual will respond to the auditory stimulus. This in turn assists them in optimizing and improving SleepLoop''s performance.
On track for market launch
Tosoo AG, a spin-off company, is further assembling the device and preparing it for the clinical market. It is already clear that it will not be freely available, but only via a medication.
When you have trouble sleeping, this is a medical device, not a wellness consumer item, according to Walter Karlen, who started the technology at ETH Zurich in May 2021. The device must be medically indicated and monitored by a doctor, he says. The development of the technology will now continue in Ulm.