By studying the electromagnetic waves produced by the brain during sleep cycles, researchers say they can predict who will be more likely to experience insomnia during periods of stress.

In studying the sleep behavior and brain activity of 12 students at the University of Concordia, in Quebec, researchers were able to predict which students were more likely to develop symptoms of insomnia during exam time.

During sleep, the brain produces a series of electromagnetic waves. The majority of these waves are generated deep in the brain from portions called thalamus and cortex. Research suggests the central purpose of these waves is to drown out potentially disruptive external stimuli and promote deeper sleep states.

Scientists can use electrodes and diagnostic tools to record these waves, and when they do, the activity resembles the squiggly lines of a lie detector test or seismograph. Researchers refer to these lines as spindles.

A previous study by Concordia researcher showed that higher numbers of spindles were correlated with deeper sleep states, and that those with consistently high spindle totals were more likely to enjoy longer periods of uninterrupted sleep.

The latest study also looked at spindle counts, both at the beginning of the semester and at the end, during exam time. Based on their previous work, researchers predicted low spindle numbers would predict a susceptibility to stress-induced insomnia.

"We found that those who had the lowest spindle activity tended to develop more disturbances in response to stress, when comparing sleep quality at the beginning of the semester and the end of the school semester," Thien Thanh Dang-Vu, the lead study author, explained in a press release. "We are not all equally armed when facing stress, in terms of how we can manage our sleep. Some people are more vulnerable than others."

As of now, Dang-Vu says, there isn't any proven remedy for those with low spindle counts; it's believed this type of brain activity is at least partially driven by genetics. But there are strategies for avoiding insomnia, and sleep spindle activity can show who may need to take on those strategies more aggressively.

"Avoid sources of stress when going to bed, preserve the bedroom environment for sleep and not for work, and avoid stimulation," Dang-Vu said. "Find ways to relax before going to sleep."

The new study was published this week in the journal Frontiers in Human Neuroscience.