Researchers are a step closer to predicting who is most likely to suffer from insomnia.

In his study, Frontiers in Human Neuroscience, Thien Thanh Dang-Vu, from Concordia's Center for Studies in Behavioral Neurobiology and PERFORM Center, explores the impact of stress on sleep. Although researchers already know that stressful events can trigger insomnia, the experiment reveals that some people are more vulnerable than others to developing the condition.

For the study, researchers examined the sleep cycles of 12 Concordia students as they went through the nerve-racking experience of finals. Measuring students' brain waves at the beginning of the school semester, Dang-Vu and his team found that students showing a lower amount of a particular pattern of brain waves were more at risk for developing insomnia afterwards in response to the stress of the exams.

The brain -- specifically the deep, inner parts of the brain called the thalamus and cortex -- produces electromagnetic activity during sleep. When monitored by diagnostic tools, this activity appears as patterns of squiggly lines that scientists refer to as spindles.

"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," Dang-Vu said. "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."

There are not a lot of ways people can get better spindles, since they seem to be at least partially dependent on genetics.

Dang-Vu, who is a medical doctor and neurologist at the Institut Universitaire de Gériatrie de Montréal, says that exploring ways to improve spindles is another prospective area for research.

The findings are detailed in the journal Frontiers in Human Neuroscience.