Insomnia may be caused by impairments in the brain's communication networks. New brain scan research reveals that insomniacs have abnormalities in their brain's white matter tracts.
The latest study involved 53 participants. Researchers noted that 23 of the participants suffered from primary insomnia, a condition characterized by difficulty falling or staying asleep for a month or longer. The other 30 participants in the control group were made up of healthy volunteers.
"Insomnia is a remarkably prevalent disorder," said Shumei Li, the lead researcher of the study. "However, its causes and consequences remain elusive."
Li and her team at the Department of Medical Imaging at Guangdong No. 2 Provincial People's Hospital in Guangzhou, China, used magnetic resonance imaging (MRI) scans to examine white matter tracts in the brains of the participants. Researchers noted that MRI scans in the current study involved a specialized technique called diffusion tensor imaging (DTI), which tracts water movement along white matter tracts. Researchers said that tracking the pattern of water movement helps determine the integrity of the white matter.
"We used a new method called Tract-Based Spatial Statistics that is highly sensitive to the microstructure of the white matter tract and provides multiple diffusion measures," Li explained.
Participants were also asked to complete a variety of questionnaires about mental status and sleep patterns. Researchers noted that some of the questionnaires included the Self-Rating Anxiety Scale, the Self-Rating Depression Scale, the Insomnia Severity Index and the Pittsburgh Sleep Quality Index.
Study analysis revealed that insomniacs had significantly worse white matter integrity in the thalamus and many parts of their right-brain regions. Li noted that the affected parts of the brain in insomniacs play a role in regulating consciousness, sleep and wakefulness.
"These impaired white matter tracts are mainly involved in the regulation of sleep and wakefulness, cognitive function and sensorimotor function," Li explained. "The involvement of the thalamus in the pathology of insomnia is particularly critical, since the thalamus houses important constituents of the body's biological clock."
Study results also revealed significant links between the length of the patients' insomnia and score on the self-rating depression scale, as well as impairments found in their brain's thalamus and body corpus callosum.
The findings were published in the journal Radiology.
