Published in the online version of the journal, Radiology, new research found brain white matter tract abnormalities in patients suffering from insomnia. These findings were made using a sophisticated MRI technique.
Primary insomnia is characterized by an individual’s inability to fall or stay asleep at night for at least one month. This type of insomnia is associated with fatigue during the day, cognitive impairment, and disruption in mood. Additionally, primary insomnia can lead to anxiety and depression disorders.
Researchers from Guangzhou, China at the Department of Medical Imaging, Guangdong No. 2 Provincial People’s Hospital, note that while insomnia is a remarkably prevalent problem, its cause and ultimate consequences remain unknown.
Lead researcher, Guihua Jiang, M.D., along with Shumei Li, M.S. and other colleagues began this research by looking at and analyzing white matter tracts in those with insomnia to see if there is a relationship between the duration and features of insomnia and abnormal white matter integrity. The white matter tracts connect different parts of the brain with bundles of axons, or long fibers of nerve cells. If these are dysfunctional, researchers state, communications between the different regions in the brain are impaired.
In this study, there were 23 individuals who were diagnosed with primary insomnia and 30 otherwise healthy individuals serving as the control group. All participants completed various questionnaires to evaluate sleep patterns and mental status. These questionnaires included the Pittsburgh Sleep Quality Index, the Self-Rating Anxiety Scale, the Self-Rating Depression Scale, and the Insomnia Severity Index.
In addition to these tests, each person had a brain MRI performed with a special technique called diffusion tensor imaging (DTI). This technique specifically evaluates the movement of water along the white matter tracts to locate any loss of integrity.
Researcher, Li, notes that they used tract-based spatial statistics - a new method that is sensitive to white matter tract microstructure and gives them various diffusion measures.
This analysis showed that patients with insomnia had significantly reduced white matter integrity in many different right-brain regions compared to healthy controls. Additionally, their thalamus was disrupted as well, which regulates sleep, alertness, and consciousness.
It is noted that the impaired tracts are linked to the regulation of wakefulness and sleep, as well as sensorimotor and cognitive functioning. Furthermore, the duration of the patient’s insomnia and self-rating depression scale scores were linked to the thalamus and body corpus callosum abnormalities. The body corpus callosum is the brain’s largest white matter structure.
The thalamus is responsible for important parts of the body’s biological clock, so its involvement in the pathology of insomnia is critical, researchers state. Additionally, this study found that the loss of myelin (the protective layered coating around nerve fibers) may play a role as an underlying cause of abnormalities in white matter integrity in insomnia patients.
As with all new findings that are critical in the study of sleep, the researchers state that further study into the relationship between white matter tract abnormalities and insomnia is needed. A larger sample to clarify this relationship would be beneficial.
Rachael Herman is a professional writer with an extensive background in medical writing, research, and language development. Her hobbies include hiking in the Rockies, cooking, and reading.
© 2020 American Sleep Association.