Studying young children who snore

Saturday 22 September 2012 12:32PM (view full episode)

Up to 35% of children snore. It causes high blood pressure which contributes to cardio vascular disease. Lauren Nisbet is studying children between the ages of 3 and 5. They do a sleep over, in a sleep lab where heart rates and blood pressure are measured. Lauren Nisbet says preschool might be a time when snoring can be treated, thus reducing the consequences of snoring evident in older children.

Add comment


Robyn Williams: And so to our PhD this week. Here's Lauren Nisbet in Melbourne.

Lauren Nisbet: We all know someone who snores, and while many of you may be thinking of your partner, did you know that children snore? Up to 35% of children regularly snore. This easily equates to more than 1 million Australian children. So why does this matter?

Cardiovascular disease is the leading cause of mortality in Australian men and women. A major contributor to cardiovascular disease is high blood pressure or hypertension, and there is a relationship between high blood pressure and snoring or sleep apnoea.

Simply put, a person suffering sleep apnoea experiences pauses in breathing during sleep, and this can happen up to hundreds of times each night, depending on severity. This significantly reduces the quality of their sleep and often leads to symptoms such as daytime sleepiness and poor concentration.

But setting specific symptoms aside, this chronic disorder has serious effects on cognition, behaviour, metabolism and the cardiovascular system. It is recognised that adults who snore or who have sleep apnoea have raised blood pressure. This occurs not just during sleep but also during the day. My research group has also established that primary school children who snore have raised blood pressure, and yet clinicians and parents still see snoring as benign and unimportant. But that is changing. Research is indicating that snoring is not without consequences.

My name is Lauren Nisbet and I'm a medical student at Monash University. I'm undertaking a PhD at the Ritchie Centre, Monash Institute of Medical Research. My PhD focuses on children aged between three and five years old because this is the age in childhood when snoring or sleep apnoea is most common. Preschool children have large tonsils in comparison to the size of their airway, and when they are asleep their airway becomes relaxed and floppy, so you can imagine how this combination can be quite problematic for their breathing.

I want to find out whether these young children's cardiovascular systems are affected by snoring and sleep apnoea. Perhaps preschool children haven't been snoring long enough to alter their blood pressure. Nobody has ever investigated the effects at this young age, so this project will provide crucial information about the onset of cardiovascular disease and will guide the approach taken by doctors and families to this common disorder.

In order to do this we needed to study a healthy group of non-snoring preschoolers as our normal comparison or control group. We then studied around 150 preschoolers who did snore and did have sleep apnoea. In total we studied just under 200 children. All the children came to the Monash Children's Sleep Centre and were involved in an overnight sleep study.

Most people have never heard of a sleep study. It means sleeping in a special bedroom for one night, and during this time we collect simultaneous physiological recordings, entirely non-invasive, to look at breathing, heart rate, blood oxygen levels and brainwaves to distinguish the type of sleep. Some of the preschoolers did find it a little daunting, but the majority had a great time. Kids love stickers, and how often are they allowed to stick them all over their body? I know that some of the children in the study went to show and tell with stories of dressing up as a robot for a really cool science experiment. The kids were great.

Now the studies are done, my current task is to analyse the recordings. Each study runs the whole night, so we have thousands of hours of data, which means this will be very time consuming. So far I have assessed heart rate fluctuations as an indicator of the functioning of the involuntary nervous system, called the autonomic nervous system. Adults with sleep apnoea have dysfunction of this involuntary nervous system, but we have found that preschool children with sleep apnoea are no different from healthy, non-snoring children in this regard.

To assess blood pressure I didn't use a blood pressure cuff, instead I used an indirect blood pressure measure through calculations from the heart rate and pulse rate in the finger. This method doesn't disrupt the children's sleep and is also non-invasive.

There are many unknowns in this field. We don't know if the children who snore during childhood will be the ones to snore as adults. Some seem to improve with time, some get worse. Importantly, we don't know the long-term effects of childhood snoring, but imagine what the long-term implications of having high blood pressure from the age of three might be.

I'm not a clinician just yet, but as a researcher I believe the preschool age may be a time can treat snore and sleep apnoea and prevent the consequences that are already evident even by primary school age.

Robyn Williams: Who'd have thought? Lauren Nisbet at Monash, another of your bright sparks inventing the future.

This is The Science Show on RN throughout the cosmos.


Lauren Nisbet
PhD Candidate
Monash Institute of Medical Research
Melbourne Victoria


Robyn Williams
David Fisher

Comments (0)

Add your comment