Sleep apnea linked to silent strokes


People with severe sleep apnea may have an increased risk of silent strokes and small lesions in the brain, according to a small study presented at the American Stroke Association’s International Stroke Conference 2012.

In the study, 56 patients—average 67 years old, white and 54% women—underwent overnight in-hospital testing for sleep apnea. Magnetic resonance imaging and computerised tomography determined silent strokes and white matter lesions. Neuroradiologists were blinded to the sleep study findings and outcome.


The researchers found that 91% (51) of the patients who had a stroke had sleep apnea and were more likely to have silent strokes and white matter lesions that increased risk of disability at hospital discharge. They also found that having more than five sleep apnea episodes per night was associated with silent strokes. More than one-third of patients with white matter lesions had severe sleep apnea and more than 50% of silent stroke patients had sleep apnea. 


“We found a surprisingly high frequency of sleep apnea in patients with stroke that underlines its clinical relevance as a stroke risk factor,” said Jessica Kepplinger, study’s lead researcher and stroke fellow in the Dresden University Stroke Center’s Department of Neurology at the University of Technology in Dresden, Germany. “Sleep apnea is widely unrecognised and still neglected. Patients who had severe sleep apnea were more likely to have silent strokes and the severity of sleep apnea increased the risk of being disabled at hospital discharge.”


Researchers suggested that sleep apnea should be treated the same as other vascular risk factors such as high blood pressure.


“Demographic characteristics in our study are comparable to western European populations, but our findings may not be entirely generalizable to other populations with diverse ethnicities such as in the USA,” Kepplinger said.


The researchers plan more studies on sleep apnea, particularly in high-risk patients with silent strokes and white matter lesions, to determine the impact of non-invasive ventilation and on short-term clinical outcome, researchers said.


Co-authors are: Kristian Barlinn, Amelia Boehme, Lars-Peder Pallesen, Wiebke Schrempf, Johannes Gerber, Karen Albright, Andrei Alexandrov and Ulf Bodechtel.