Fast spindles ensure a good night’s sleep

In today’s noise polluted world, getting a good night sleep can be difficult, but scientists hope to enhance a person’s shut-eye after discovering the brain’s rhythm controls the amount of sleep we get.

Scientists from Massachusetts General Hospital (MGH) studied the brain activity of 12 healthy adult volunteers over three nights – one quiet and two noisy – focusing on a features which only appears during sleep, spindles.

“We wanted to investigate what the brain does to promote stable sleep, even in the face of noise, and why some people are better at staying asleep than others,” said Jeffrey Ellenbogen, chief of the MGH division of sleep medicine, “Understanding the tools and techniques the brain naturally uses could help us harness and expand those responses to help stay asleep in noisy environments.”

Participants were subjected to various noises – telephones ringing, people talking and hospital mechanical sounds. EEG readings were taken throughout the night recording fluctuations in the brain’s electrical field until they indicated the participants were awake.

“We found that by measuring brain waves during sleep, we could learn a lot about how well a person’s brain can block the negative effect of sounds,” said Ellenborg, “The more sleep spindles your brain produces, the more likely you are to stay asleep.”

Ellenborg explained that during sleep, brain waves become slow and organised – sleep spindles are bursts of faster frequency waves generated by the thalamus. The thalamus is thought to be preventing unwanted sensory information from entering the brain to stop reaction to the sounds.

The team found that each participant maintained a consistent night-to-night spindle rate, those with higher rates were more likely to have a better night’s sleep. Ellenborg notes that participants were often not aware that their sleep had been interrupted; suggesting environmental noise may have more of an effect than realised.

They now hope to research behavioural techniques, drugs or devices that may enhance sleep spindles to help people stay asleep when subjected to noise, especially those in hospital environments.

“Our sleeping environments have gotten increasingly complex and problematic, with all the beeps and boops of our 24/7 modern crowded lives,” said Ellenborg. “Our goal is to find brain-based solutions that integrate a sleeping person into their modern environment, such that sleep is maintained even in the face of noises.”