Sleepless nights? Chances are, if you suffer from insomnia, your brain doesn't quite know how to switch off.
Chronic insomnia affects about 15 percent of Americans, with recent research suggesting that brain activity is the root of the problem. The study, led by Dr. Rachel Salas, an assistant professor of neurology at Johns Hopkins University School of Medicine, looked at the brain activity of 28 individuals: 18 insomniacs and 10 sound sleepers. The research team used electrodes around the skull to stimulate the brain, a process called transcranial magnetic stimulation, or TMS. By distributing electromagnetic currents to chosen areas of the brain (a pain-free procedure), Salas was able to measure brain activity - and thus brain plasticity, or adaptability - by using electroencephalograms (EEG) to observe voltage fluctuations.
The insomniacs and the sleepers were required to perform basic tasks that mimicked the reverse of movements prompted by TMS. Based on prior studies, which demonstrated that insomniacs have issues with concentration and memorization, Salas expected them to have some difficulty with these tasks. However, the opposite was revealed to be true, with enhanced plasticity contributing to quicker learning of the task. It also revealed equally high levels of brain activity running from day through to night, suggesting that the condition is in fact a pervasive one that is present at all hours. "Insomnia is not a nighttime disorder," said Salas. "It's a 24-hour brain condition, like a light switch that is always on. Our research adds information about differences in the brain associated with it."
From this, it's now thought that increased plasticity means a constantly stimulated brain that's unable to wind down to sleep in the same way that sound sleepers can. "Their brain waves look different from good sleepers," said Dr. Salas of insomniacs. "Traditionally in normal sleep, the brain waves slow down, become more synchronous and get into a nice delta wave for sleep. Insomniacs may get into delta sleep, but they have other faster rhythms riding on top of their EEG." The insomniacs tested also had higher levels of the stress hormone cortisol, further lending weight to Salas' findings.
While the study found disparate brain patterns between the insomniacs and the sound sleepers, it hasn't identified the cause: whether it's a hyper-functioning brain, or if disruption leads to the brain being more excited. Nevertheless, Salas and her team are eager to see more research done in the area, particularly around targeting brain activity as a form of treatment for insomnia.
The study, titled Increased Use-Dependent Plasticity in Chronic Insomnia, appears in the March 2014 edition of the journal Sleep.
