We speak a lot about how factors like excess weight, smoking, and enlarged tonsils can increase the chance of breathing obstruction, and thus apneas, during the night. In these cases, sleep apnea comes from an airway-related issue. However, since the propensity to breathe originates in the brain, some may suffer from apneas when brain circuits get faulty or are damaged. Central apneas, for example, occur when signals from the brain stop telling the body to breathe. It is unknown, however, whether the prevalence of sleep apnea is increased in those who have suffered from stroke-related brain injury. Therefore, a recent study set out to study this possible link.
Using 355 subjects who had recently suffered from a stroke, the research team first wanted to determine how many of these subjects had injury in the brainstem. This area was selected because breathing mechanisms often originate from this area. It was found that 39 of these subjects had brainstem injury, as determined by neuroimaging (MRI and CT scans). These subjects then underwent home sleep testing for the assessment of sleep apnea presence and severity.
Amazingly, results showed that 84% of these subjects suffered from sleep apnea. The rest of the population who suffered from a stroke was screened, and it was found that 59% of that population also suffered from sleep apnea1.
This study found an unusually high amount of sleep apnea sufferers in a population who recently suffered sustained brainstem damage from a stroke. Also of note, though, is that the population of stroke sufferers without damage to this area also had a high prevalence of stroke. This high coincidence likely stems from the fact that unhealthy lifestyle habits (smoking, obesity, etc.) are risk factors for both sleep apnea and stroke. It is likely that a large chunk of these stroke sufferers may have had sleep apnea prior to their stroke and simply had never been diagnosed. However, it is still significant that those with brainstem injury do suffer from higher rates of sleep apnea. Since we have previously seen that treating sleep apnea may reduce the risk for onset of an additional stroke, it is extremely important for recent stroke sufferers to undergo sleep apnea screening and seek treatment as soon as possible.
1. American Stroke Association's International Stroke Conference 2014 Presentation: Source: http://medicalxpress.com/news/2014-02-apnea-common-stroke-related-brainstem-injuries.html