Findings from sleep research put into practice: Researchers have developed a wearable device that plays sounds to sleepers at exactly the right time, which can lead to an intensification of the deep sleep phases. The first clinical study has now confirmed the effectiveness of this so-called SleepLoop system. However, apparently not everyone reacts equally well to the concept. Further adjustments to the system could potentially improve this, the developers say.
Weak, nervous and unfocused: It is well known that too little or bad sleep can lead to unpleasant physical and mental symptoms and thus have a significant impact on people’s quality of life. This is a widespread problem, but older people are particularly affected. Deep sleep in particular is often impaired in them. This important part of healthy sleep is marked by a slow wave of brain activity. Studies have shown that the corresponding phases become shorter and less deep with age. In particularly pronounced cases, this can have a very negative effect on a person. Because a healthy deep sleep is important for the regeneration of the brain, memory and the cardiovascular system.
Auditory brain stimulation
Previous studies have shown that the quality of deep sleep can be improved by an amazing method: auditory brain stimulation. These vibrations are amplified by playing click tones in sync with the rhythm of the slow brain waves of sleeping people. With the technical equipment in sleep laboratories, scientists have already been able to successfully promote the quality of the deep sleep of test persons. So far, however, there has been no everyday option for patients to treat themselves with the procedure at home over a longer period of time. But that could soon change: in recent years, the researchers working with Caroline Lustenberger from ETH Zurich have developed a mobile device that can also be used in your own bed. The team is now reporting on their SleepLoop system and the first test results.
The device is a type of hood made of ties that is put on at bedtime and worn during sleep. The units have electrodes that constantly measure the brain activity of the sleeping person and transmit the data to a microchip. There they are processed autonomously with specially developed software and then set the pace for the other functions of the device: As soon as the sleeping person develops the brain waves that are characteristic of deep sleep, the system triggers the short auditory signal. This click is not consciously perceived by the sleeper and is intended to stimulate the nerve cells to intensify the deep sleep waves. This effect is in turn also documented via the device.
To what extent the SleepLoop system can keep what it promises, the scientists have now tested on a group of volunteers aged between 62 and 78 years. For this first clinical examination of the system, it was not about patients, but about test persons with a normal deep sleep according to their age. For the study, they wore the device for a total of one month. There was stimulation every night for two weeks, but in the other two weeks the system did not produce any click sounds as a control. Neither the subjects nor the experimenters knew in which two weeks the auditory signals were recorded and in which not.
Positive test result
A fundamental question in the context of the study was initially how the study participants coped with the independent operation of the SleepLoop system in practice. As the researchers report, it turned out that they had succeeded in developing a user-friendly device: “The device worked very well: We had surprisingly little data loss and the study participants rated the device as user-friendly,” reports Lustenberger. The evaluation of the results of 16 test persons then made it clear that the portable device can actually cause auditory brain stimulation: “Some test persons generally reacted well to the stimuli and showed clearly amplified deep sleep waves,” reports Lustenberger. However, it was also shown that this was not generally the case – the study results showed that the effect varied greatly from person to person: “There were also test persons who did not react to the stimuli,” reports Lustenberger.
As the researchers explain, it is becoming apparent that this is related to the different natural activity of the slow brain waves in the test subjects. These individual differences should now be used to improve the predictions of how someone will react to the auditory stimulus. This in turn could help to further optimize the SleepLoop system. According to the scientists, personalized adjustments may lead to a compensation. So now they hope that after further testing and optimization, the system will soon be able to benefit people with disorders of the deep sleep system.
As ETH Zurich reports, the results have already led to the founding of a company to further develop the device and bring it to market. However, senior author Walter Karlen emphasizes that the SleepLoop system will only be available with a doctor’s prescription. “It’s not going to be a wellness consumer product that you can just buy online when you’re having a bad night’s sleep,” says Karlen. “Because it is a special medical technology product that must be medically indicated and the use of which requires medical supervision,” the scientist concludes.
Source: ETH Zurich, specialist article: Commun Med, doi: 10.1038/s43856-022-00096-6