Silent strokes and sleep apnoea

2nd February 2012 - People with severe sleep apnoea may have an increased risk of silent strokes and small lesions in the brain, according to a German study presented at the American Stroke Association’s International Conference.

The study's lead researcher, Dr Jessica Kepplinger, from Dresden University Stroke Center’s Department of Neurology, said in a press release: "We found a surprisingly high frequency of sleep apnoea in patients with stroke that underlines its clinical relevance as a stroke risk factor."

Sleep apnoea

Sleep apnoea is a condition where breathing temporarily stops during sleep. This automatically forces the sleeper to wake up in order to start breathing again. This can happen a number of times during the night making it hard for the body to get enough oxygen and obtain good quality sleep.

Extremely loud snoring, excessive daytime sleepiness and morning headaches are some of the symptoms of sleep apnoea. Left untreated it can increase the risk of high blood pressure, heart attack, obesity and, as this study shows, stroke.

Marianne Davey co-founder of the British Snoring & Sleep Apnoea Association told us the findings of this latest study are nothing new but more and more people are now beginning to understand the seriousness of sleep apnoea.

"My main message to the general public, and snorers in general, would be if you know you're a snorer or think you might have sleep apnoea get yourself treated sooner rather than later and avoid all of these problems."

Findings

The patients, who had an average age of 67, underwent overnight in-hospital testing for sleep apnoea. Silent strokes and white matter lesions were determined by using magnetic resonance imaging and computerised tomography.  

The researchers found:

• 91% (51 of 56) of patients who had a stroke had sleep apnoea and were more likely to have silent strokes and white matter lesions that increased the risk of disability when it came to leaving hospital.
• Having more than five sleep apnoea episodes per night was associated with silent strokes.
• More than one-third of patients with white matter lesions had severe sleep apnoea and more than 50% of silent stroke patients had sleep apnoea.
• Even though men were more likely to have silent infarcts, (a stroke without symptoms) correlations between sleep apnoea and silent infarcts remained the same after adjustment for gender differences.

The future

The study researchers have suggested that sleep apnoea should be treated in the same way as other vascular risk factors such as high blood pressure. They're also planning more studies on sleep apnoea, 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.

These findings were presented at a medical conference. They should be considered preliminary as they have not yet undergone the "peer review" process, in which outside experts scrutinise the data prior to publication in a medical journal.