A new brain imaging study reveals structural brain changes in patients with sleep apnea as well as distinct differences between males and females with the condition.
Obstructive sleep apnea, a disorder which involves disruption of the upper airway, affects about 10 percent of adults. Men are twice as likely to have the condition as women, and symptoms and brain function appear to vary between sexes. When left untreated, the effects of sleep apnea on brain damage increases over time. Its cause is still unknown.
For the study, researchers from the University of California, Los Angeles (UCLA) School of Nursing looked at the brain scans and clinical records of patients who recently had been diagnosed with sleep apnea.
Using high-resolution magnetic resonance imaging (MRI) scans, the researchers analyzed the cortex thickness of 12 women and 36 men who had diagnoses of mild to severe obstructive sleep apnea (who were not being treated for their condition), and compared those findings to 40 male and 22 female healthy controls. The researchers then compared clinical findings of each patient with evidence of cortex thinning.
Not only did they discover several connections between apnea symptoms and thinning of the brain’s cerebral cortex, but they also found distinct differences between men and women when it came to brain structure and concurrent symptoms.
For example, more regions of the superior frontal lobe were thinner in women with apnea than in men with apnea or control groups, which might explain the greater cognitive deficits often found among women with the condition.
In addition, overall cortical thinning could potentially result in poor regulation of the autonomic nervous system and the associated upper-airway breathing dysfunction typically seen in these patients. No sleep apnea patients showed any thickening of the cerebral cortex.
Although previous research has shown a link between brain structure changes and general clinical signs, no studies have definitively linked gender differences in brain structure with apnea symptoms.
The current study is one of the first to reveal significant clinical differences between men and women with sleep apnea, and points to the need for different treatment approaches in addressing these varied symptoms.
Overall, the greater cortex injury in the cognitive centers of women’s brains may help explain why female apnea patients tend to have more severe cognitive problems than men with the condition. In addition, the thinning associated with both men and women who have sleep apnea may be behind the disordered breathing seen in both sexes.
It is still unclear, however, whether these physical brain changes precede the sleep apnea disorder, or worsen sleep apnea’s symptoms as the disorder progresses.