February 28, 2014
Science Daily/Johns Hopkins Medicine
Researchers report that people with chronic insomnia show more plasticity and activity than good sleepers in the part of the brain that controls movement. "Insomnia is not a nighttime disorder," says study leader, Rachel E. Salas, M.D., an assistant professor of neurology. "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." The researchers say they hope their study opens the door to better diagnosis and treatment of the most common and often intractable sleep disorder that affects an estimated 15 percent of the United States population.
Because lack of sleep at night has been linked to decreased memory and concentration during the day, Salas and her colleagues suspected that the brains of good sleepers could be more easily retrained. The results, however, were the opposite. The researchers found much more plasticity in the brains of those with chronic insomnia.
Salas says the origins of increased plasticity in insomniacs are unclear, and it is not known whether the increase is the cause of insomnia. It is also unknown whether this increased plasticity is beneficial, the source of the problem or part of a compensatory mechanism to address the consequences of sleep deprivation associated with chronic insomnia. Patients with chronic phantom pain after limb amputation and with dystonia, a neurological movement disorder in which sustained muscle contractions cause twisting and repetitive movements, also have increased brain plasticity in the motor cortex, but to detrimental effect.
Salas says it is possible that the dysregulation of arousal described in chronic insomnia -- increased metabolism, increased cortisol levels, constant worrying -- might be linked to increased plasticity in some way. Diagnosing insomnia is solely based on what the patient reports to the provider; there is no objective test. Neither is there a single treatment that works for all people with insomnia. Treatment can be a hit or miss in many patients.