This study is the first to assess gray matter concentration in OSA patients with both modulated and unmodulated MRI images
A study in the Feb. 1 issue of the journal SLEEP found gray matter concentration deficits in multiple brain areas of people with severe obstructive sleep apnea (OSA). The study suggests that the memory impairment, cardiovascular disturbances, executive dysfunctions, and dysregulation of autonomic and respiratory control frequently observed in OSA patients may be related to morphological changes in brain structure.
Results indicate that in newly diagnosed men with severe OSA, gray matter concentrations were significantly decreased in multiple brain areas, including limbic structures, prefrontal cortices and the cerebellum. Optimized voxel-based morphometry, an automated processing technique for magnetic resonance imaging (MRI), was used to characterize structural differences in gray matter by examining the entire brain, rather than a particular region.
"Gray matter" refers to the cerebral cortex, where most information processing in the brain takes place. It is a layer of tissue that coats the surface of the cerebrum and the cerebellum and is gray in appearance, lacking the myelin insulation that makes most other parts of the brain appear to be white.
Principal investigator Seung Bong Hong, MD, PhD, professor of neurology at the Samsung Medical Center in Sungkyunkwan University School of Medicine in Seoul, South Korea, said the study emphasizes the importance of diagnosing and effectively treating severe OSA.
"Poor sleep quality and progressive brain damage induced by OSA could be responsible for poor memory, emotional problems, decreased cognitive functioning and increased cardiovascular disturbances," said Hong. "The use of continuous positive airway pressure - CPAP - therapy could stop further progression of brain damage in patients with severe OSA."
The study involved 36 male OSA patients with an average age of 44.7 years and 31 healthy, male, age-matched controls. Sleep was evaluated by overnight polysomnography. The OSA patients had a mean apnea-hypopnea index (AHI) of 52.5 partial and complete breathing pauses per hour of sleep; an AHI of more than 30 is considered severe OSA. Patients with OSA also had more awakenings from sleep and a more fragmented sleep structure than controls.