Many people, especially the elderly, suffer from abnormal sleep. In particular, the deep sleep phases become shorter and shallower with age. Deep sleep is important for the regeneration of the brain and memory, and also has a positive influence on the cardiovascular system.
Researchers have shown that the brain waves characterizing deep sleep, 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 been no at home solution that can be used longer than just one night.
SleepLoop to the rescue
As part of the SleepLoop project (see illustration), researchers at ETH Zurich have developed a mobile system that can be used at home and aims to promote deep sleep through auditory brain stimulation.
The SleepLoop system consists of a headband that is put on at bedtime and worn throughout the night. This headband contains electrodes and a microchip that constantly measure the brain activity of the person sleeping. Data from this is analysed autonomously in real-time on the microchip using custom software. As soon as the sleeping person shows slow waves in the brain activity characterizing deep sleep, the system triggers a short auditory signal (clicking). This helps to synchronize the neuronal cells and enhance the slow waves. What makes the solution unique is that the person sleeping is not consciously aware of this sound during deep sleep.