Sleep apnea is associated with an increased risk of symptomless strokes called 'silent strokes'.
The German researchers studied 56 men and women, aged 44 to 75 years, who had a history of stroke or mini-stroke (transient ischemic attack). With the help of a screening tool that picks up changes in breathing during sleep, it was noted that 91% periodically stopped breathing while they slept. Brain imaging scans revealed that more than half the subjects had little areas of tissue death in the brain that had occurred in the past without a history of corresponding stroke symptoms- which is an evidence of silent stroke. The likelihood of silent stroke corresponds to the number of times a person stopped breathing during the night.
However, as there was no comparison group, the researchers do not know how many people of the same ages and health status who do not have sleep apnea have had silent strokes.
The findings were presented at the 'American Stroke Association's International Stroke Conference'.