Sleep disorders: to be rocked makes you sleep better.
Do like babies , get rocked! According to Swiss research, this improves the quality of sleep and its duration, whatever the age. In 2011, a study already showed the interest of rocking during a nap. If it allows to fall a sleep faster and more deeply, this time, the researchers were interested in its effects on a full night. Led by the University of Geneva (Unige) and the University of Lausanne (Unil), the work was published in the journal Current Biology.
Three nights to study sleep
18 participants were recruited by the research team. Their sleep was studied for three nights: the first allowed them to get used to the place, then they were slowly cradled the second night in a bed suspended by 4 cables. The movement was generated by a silent engine – a round trip lasted about 4 seconds and extended about ten centimeters. Finally, the participants slept in a classic bed the last night.
The positive effects of cradling on memory
According to their observation, being rocked during the night makes it easier to fall asleep and to have a better sleep : deeper and with fewer micro-alarms. Instruments were placed on the volunteers to record various parameters, including brain activity. The electroencephalogram readings showed the presence of slow brain waves in large quantities, just for deep sleep.
The researchers wanted to make sure that the volunteers had felt the benefits of better sleep. To do this, they studied the effects of cradling on their memory , knowing that deep sleep strengthens it. Before falling asleep, participants had to learn pairs of words and then recite them the next day. The rocking allowed them to have better results: they remembered more words .
The researchers wanted to understand how rocking could affect the brain. The Lausanne team took care of this part of the study using mice. The cages were simply placed on an agitator to rock slowly, a tool used regularly in the laboratory. Two types of mice were used: the first were “normal”, the second had a vestibular system (an organ located in the inner ear) altered.
Rocking allowed the first group of mice to sleep longer, but no effect was seen on the others. For scientists, this is proof that rocking acts on the vestibular system. They now want to continue their research to discover how this action on the inner ear is reflected in the cortex. The results could be used to develop new treatment options to fight against insomnia or memory problems.