What happens to a child’s brain when they snore?

Associate Professor
Dr David McIntosh
MBBS FRACS PhD
Paediatric Ear Nose and Throat Specialist
entspecialists.com.au

WHAT IS SNORING
Snoring is a noise that is made when there is either a blockage of airflow,
or a disturbance in the normal airflow pattern
Specifically this relates to problems in the breathing somewhere between
the nose to the voice box
There are other noises related to noisy breathing, but as snoring is the
most common, it is the most important
Associate Professor Dr David McIntosh

ARE KIDS MEANT TO SNORE?
All too often, snoring by kids is ignored by parents
Whilst snoring is normal if it is intermittent, such as when the child is sick
with a cold, or is really tired from a busy day of activity, persistent
snoring is not normal
We now call persistent snoring habitual if it is present for 4 nights of the
week, or more
Habitual snoring is the lesser form of airway obstruction that we
collectively call “Sleep Disordered Breathing” or SDB for short
At the worst end of the spectrum of SDB is obstructive sleep apnoea (OSA)-
this is where the blockage is so bad that there is no air flowing into the
lungs at all-and this is a very bad thing

CAN WE MEASURE OBSTRUCTED SLEEP?
An investigation called a sleep study is an excellent test for diagnosing
sleep apnoea in children
The problem is that this diagnosis is only part of the whole spectrum of
sleep disordered breathing
In fact there are questions as to sensitivity of sleep studies
The reason for this is that we now know the importance of subtle hypoxia
and brain arousal on brain function. The problem is we don’t tend to
measure these in kids when we do sleep studies. This also means a lot
of kids are not getting treated.
Biggs SN et al. Sleep Med Rev. 2014 Dec;18(6):463-75.
The conundrum of primary snoring in children: what are we missing in
regards to cognitive and behavioural morbidity?

BREATHING AND THE BRAIN
Breathing is an automated process, controlled by the brain
By monitoring chemical levels in the blood, the brain can work out if the
breathing is working properly
If the signals to the brain indicate that something is wrong, the brain can
alter the rate of breathing to compensate
The problem of airway obstruction though is that even if the brain
recognises there is a problem, increasing the effort of breathing
achieves very little
Furthermore, blockage to breathing results in oxygen levels in the blood
dropping. This is something the brain does not like very much. It
triggers off a whole series of problems, which is what this talk is all
about.

HOW THE BRAIN WORKS
The brain is incredibly complex. So complex we still don’t fully understand
it. But we know the basics.
The brain is the control system for the nervous system. For it to work, it
needs oxygen- lots of it. If it starts to miss out on oxygen, it quickly
panics. This causes all sorts of changes that we can observe and
measure.
The other important part of the nervous system is to be able to send
signals from one place to another. The way these signals are
transmitted is via little chemicals. We call these chemical
neurotransmitters. And we can measure these also.
When we sleep, it is very important that the brain be allowed to work
uninterrupted by distractions. Any unsettling events, including low
oxygen levels, affect the architecture of sleep in an adverse way.

WHAT SORT OF PROBLEMS DO WE SEE
In children that snore we can observe the following:
reduced attention
higher levels of social problems
higher levels of anxiety
higher levels of depressive symptoms
daytime sleepiness
cognitive dysfunctions,
problems with memory,
problems with executive functions (thinking through problems
logically)

BLOOD FLOW TO THE BRAIN
In children that snore, their oxygen levels drop. As a result, the brain needs
to make some changes.
One of the ways it can try and get more oxygen in is to try and increase the
breathing.
The other way is to change the flow of blood to the brain. And this is
exactly what we have seen happen.
Hill CM et al. Pediatrics. 2006 Oct;118(4):e1100-8.
Increased cerebral blood flow velocity in children with mild sleep-
disordered breathing: a possible association with abnormal
neuropsychological function.
It is complicated, but the fact that kids with minimal measurable airway
obstruction demonstrated changed in the amount of blood being sent to
the brain. is an important finding.

BLOOD FLOW TO THE BRAIN AFTER SURGERY
To make things even more interesting, once the airway obstruction is fixed,
the blood flow changes resort back to normal levels. So too do the
oxygen levels.
Hogan AM et al. Pediatrics. 2008 Jul;122(1):75-82.
Cerebral blood flow velocity and cognition in children before and after
adenotonsillectomy.
This study and the previous also showed that children with the snoring and
altered blood flow had issues with their brain function, as measured by
their ability to think through puzzles and problems.
Their concentration also improved once the airway blockages were fixed.

THE EYES- THE WINDOW TO THE SOUL- AND THE
BRAIN
It is easier to perform eye tests on adults than kids. By looking into the eye
itself, we can actually see the nerves and brain fluid around these
nerve.
In doing so we have found that in adults with OSA, the nerve fibres are
damaged, and that the brain fluid pressure is elevated.
Xin C et al. Sleep Breath. 2015 Mar;19(1):129-34.
Changes of visual field and optic nerve fiber layer in patients with
OSAS.
These changes decrease the function of the visual system
Claudio L et al. Sleep. 2015 Jul 24.
Optic Nerve Dysfunction in Obstructive Sleep Apnea: An
Electrophysiological Study.

CHANGES IN BRAIN ACTIVITY WITH
OBSTRUCTED BREATHING
We can measure brain wave activity by using special sensors on the head.
This is called an EEG.
In children with OSA, we can see problems, with the brain wave activity
adversely affected.
Miano S et al.Sleep. 2009 Apr;32(4):522-9.
Prevalence of EEG paroxysmal activity in a population of children with
obstructive sleep apnea syndrome.
Altered brain activity during the night interrupts a smooth sleep pattern.
This seems to translate in to behavioural and mood problems during the
day.
Aronen ET et al. J Dev Behav Pediatr. 2009 Apr;30(2):107-14.
Mood is associated with snoring in preschool-aged children.
ADHD is becoming a common diagnosis. It may be that it has a lot to do
with sleep.

ADHD- DID WE GET IT WRONG?
Children that are inattentive and disruptive may be given the diagnosis of
ADHD.
The problem is that children that snore are inattentive also.
Barnes ME et al. Dev Neuropsychol. 2009;34(5):629-49.
Impairments in attention in occasionally snoring children: an event-
related potential study.
They also have problems processing speech, which means their ability to
follow instructions is compromised.
Key AP et al. Dev Neuropsychol. 2009;34(5):615-28.
Sleep-disordered breathing affects auditory processing in 5-7-year-old
children: evidence from brain recordings.

ADHD- DID WE GET IT WRONG?
When a review of the research on sleep and ADHD was done, 12 studies
were identified that had assessed the pre- versus post-surgery ADHD
symptoms of children.
The results suggested removing the tonsils and adenoids was associated
with decreased ADHD symptoms at 2–13 months post-surgery.
Sedky K et al. Sleep Medicine Review 2014, 18(4), 349-356.
Attention deficit hyperactivity disorder and sleep disordered breathing
in pediatric populations: A meta-analysis.
So before a diagnosis of ADHD is entertained, sleep disordered breathing in
a child should be assessed for first.
Fidan T et al. Eurasian J Med. 2008 Apr;40(1):14-7.
The impact of adenotonsillectomy on attention-deficit hyperactivity and
disruptive behavioral symptoms.

THE BIG STUDY- 11,000 KIDS!
Bonuck K et al. Pediatrics. 2012 Apr;129(4):e857-65.
Sleep-disordered breathing in a population-based cohort: behavioral
outcomes at 4 and 7 years.
These researchers assessed more than 11,000 children over a period of six
years, beginning at 6 months of age
Children that were snoring, breathing through the mouth, or had sleep apnoea
had a higher incidence of behavioural and emotional issues such as
hyperactivity, aggressiveness, depression, and anxiety.
They were 50 to 90 percent more likely to develop ADHD-like symptoms than
were normal breathers.
Those children who suffered most severely from sleep-disordered breathing at
around age 2½ had the highest risk for hyperactivity.
Children who stopped snoring over time, were still more likely to have problems
than children that had never snored.
Early intervention was strongly recommended, as opposed to the wait and see
approach.

TEETH GRINDING IN KIDS- WHY ARE THEY
“STRESSED”?
Grinding the teeth at night is called bruxism. In some children it can be so
bad that they can actually crack and chip their teeth.
Historically, teeth grinding was thought to be a psychological problem. The
issue is that nobody stopped to think why little kids were stressed.
What we now know is that in kids who grind their teeth and who have an
airway problem, once the airway problem is fixed, 80% of them also
stop grinding their teeth. They are stressed becuase they can’t breathe
properly.
Eftekharian A et al. Int J Pediatr Otorhinolaryngol. 2008 Apr;72(4):509-11.
Bruxism and adenotonsillectomy.
DiFrancesco RC et al. Int J Pediatr Otorhinolaryngol. 2004 Apr;68(4):441-5.
Improvement of bruxism after T & A surgery.

TEETH GRINDING AND LOW OXYGEN LEVELS
With teeth grinding being the most obvious form of abnormal jaw
movement due to the noise made as the teeth clash against each other,
there are also subtle jaw movements that we can measure.
Interestingly, these small movements seem to relate to intermittent low
oxygen levels.
Dumais IE et al. J Oral Rehabil. 2015 Jul 1.
Could transient hypoxia be associated with rhythmic masticatory
muscle activity in sleep bruxism in the absence of sleep-disordered
breathing? A preliminary report.
Teeth grinding also seems to tie in with changes in blood pressure. We will
come back to mentioning blood pressure later on.
Nashed A et al. Sleep. 2012 Apr 1;35(4):529-36.
Sleep bruxism is associated with a rise in arterial blood pressure.

CHANGES IN BRAIN TRANSMITTERS
In bruxism, we can see changes in the levels of neurotransmitters. This
includes serotonin and dopamine.
Mayer P et al. Chest. 2015 Jul 30.
Sleep Bruxism in Respiratory Medicine Practice.
These neurotransmitters are also implicated in depression.
And sleep disordered breathing is implicated in depression and other
psychological problems in kids.
Lee CH et al. Int J Pediatr Otorhinolaryngol. 2014 Dec;78(12):2145-50.
Psychological screening for the children with habitual snoring.

MOUTH BREATHING- NOT AS GOOD AS
THROUGH THE NOSE
Although the air drawn in to the body is the same, there is a big difference
as to whether it comes via the nose or the mouth.
In mouth breathing, which occurs w=in children when the nose is blocked,
the blood oxygen levels drop. This causes all the problems mentioned
so far, even if they don’t snore.
Niaki EA et al. Acta Med Iran. 2010 Jan-Feb;48(1):9-11.
Evaluation of oxygen saturation by pulse-oximetry in mouth breathing
patients.

AND IT’S NOT JUST THE BRAIN THAT SUFFERS
Apart from all the problems with brain function, sleep disordered breathing
in children also has adverse effects on the heart and blood pressure.
Walter LM et al. Sleep Breath. 2013 May;17(2):605-13.
Autonomic dysfunction in children with sleep disordered breathing.
In fact, it may very well be that the high blood pressure experienced in
adulthood stems from sleep problems as a child.
Vlahandonis A et al. Sleep Med Rev. 2013 Feb;17(1):75-85.
Does treatment of SDB in children improve cardiovascular outcome?
And many children are not being treated appropriately.
Nisbet LC et al. Sleep Med Rev. 2014 Apr;18(2):179-89.
Blood pressure regulation, autonomic control and sleep disordered
breathing in children.

THE CONSEQUENCES OF POOR SLEEP OVER
TIME
Poor sleep adds up over time. In this study, the chances of developing
dementia increased as the sleep quality decreased.
Tsapanou A et al. Dement Geriatr Cogn Dis Extra. 2015 Jul 10;5(2):286-95.
Daytime Sleepiness and Sleep Inadequacy as Risk Factors for
Dementia.
There are many causes for a bad night’s sleep. And one of them is sleep
apnoea.
Gagnon K et al. Pathol Biol (Paris). 2014 Oct;62(5):233-40.
Cognitive impairment in obstructive sleep apnea.

BRAIN SCANS AND POOR MOTOR SKILLS
Believe it or not, we now have the technology to measure brain function.
We can also measure the size of the brain.
In kids with sleep disordered breathing, the parts of the brain responsible
for thinking, conflict resolution, and attention are struggling to perform.
Kheirandish-Gozal L et al. Sleep. 2014 Mar 1;37(3):587-92.
Preliminary functional MRI neural correlates of executive functioning
and empathy in children with obstructive sleep apnea.
Furthermore, these kids have smaller brains and problems with their fine
motor skills.
Chan KC et al. Sleep Med. 2014 Sep;15(9):1055-61.
Neurocognitive dysfunction and grey matter density deficit in children
with obstructive sleep apnoea.

OSA AND ALZHEIMER’S DISEASE
Alzheimer’s disease is the most common cause of dementia. It is
characterised by a build up of protein in the brain called amyloid. It is
though that this build up affects the communication system within the
brain.
In studies of mice, where their oxygen levels were decreased, their brains
started to show a build up of amyloid.
Daulatzai MA. Neurotox Res. 2013 Aug;24(2):216-43.
Death by a thousand cuts in Alzheimer's disease: hypoxia--the
prodrome.

HOW BIG IS THE PROBLEM?
More than 25% of all children, not just those with
ADHD, will have a sleep disorder at some point.
These have enormous and varying impacts on
family dynamics, school success and other
health issues.

SO WHAT NEXT?
Children are not supposed to snore
If they snore 4 nights of the week, or more, or they mouth breathe, or grind
their teeth, there is now enough evidence to warrant a specialist review
Such a review must comprehensively assess the airway to look for
obstruction
Where such obstruction exists, treatment needs to be expedient to have the
best outcome for the child and their brain

DAVID MCINTOSH
David McIntosh is an ear nose and throat surgeon, based in Queensland,
Australia.
He holds a fellowship with the Royal Australasian College of Surgeons in
ENT and head and neck surgery.
He was awarded a PhD for his research studies in the healing process after
sinus surgery by the University of Adelaide in 2006.
In 2007 he completed a Paediatric ENT Fellowship at the Starship
Children’s Hospital, in Auckland New Zealand.
He is an international speaker, runs courses for health professionals on
ENT conditions, and has been published in major international peer
reviewed journals.
In 2014 he was granted the title of Adjunct Associate Professor of ENT by
James Cook University.

What happens to a child’s brain when they snore?

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What happens to a child’s brain when they snore?