Snoring Sleep Apnoea

I think I have sleep apnoea – Which type of sleep study is suitable for me?

February 1, 2020
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In his ENT practice, Dr Gan often sees patients who suffer from loud snoring, choking or gasping episodes during sleep and excessive daytime sleepiness. These are symptoms that are suggestive of a condition called obstructive sleep apnoea (OSA). OSA is a condition in which a person repeatedly stop breathing or chokes for a brief period of time during their sleep. As a result, they do not get enough oxygen carried to their lungs, heart and brain. This can have severe health consequences (refer to https://www.drganent.com/snoring-recommended-ent.html for more information). The only way to confirm the absence or presence of OSA is to undergo a Sleep Study. However, with so many types of sleep study available, patients and some doctors are confused. In this article, Dr Gan explains the different types of sleep study for diagnosing OSA and their indications.

 

 

What is a sleep study?

 

A sleep study is an overnight study which involves the placement of different sensors on the body to monitor the amount and quality of sleep as well as the body’s physiological activities during sleep. It also monitors whether the patient chokes or stop breathing during sleep (collective index is known as Apnoea-Hypopnoea Index or AHI, which is used to diagnose OSA).

 

 

What are the types of sleep study available for the diagnosis of OSA?

 

Level 1 sleep study (Polysomnography – PSG)

 

  • Done overnight in a Sleep Laboratory or Hospital
  • Attended by a trained Sleep Technologist
  • Monitors at least 7 parameters – e.g. brain waves, heartbeats, breathing, oxygen level in your blood, eye movement and arms/legs movements during sleep (Figure 1)

 

 

Figure 1 – A full level 1 Sleep Study done in a hospital 

 

 

Level 2 sleep study

 

  • Done at home
  • Unattended by a trained Sleep Technologist
  • Monitors the same parameters as a Level 1 sleep study

 

 

Level 3 sleep study (e.g WatchPAT study)

 

  • Done at home
  • Unattended by a trained Sleep Technologist
  • Monitors at least 4 parameters – e.g oxygen level, heart rate body position, snoring and other parameters while you sleep

 

 

Level 4 sleep study (Sleep Apnoea Screening)

 

  • Done at home
  • Unattended by a trained Sleep Technologist
  • Monitors 2 parameters –  e.g blood oxygen level, heart rate or airflow  

 

 

Can my sleep study be done at home?

 

If you’ve been asked to do any of the level 2 to 4 sleep study, it can be done at home. Having a sleep study performed at home has the advantage of eliminating anxiety associated with sleeping in a foreign environment.

 

 

Who should undergo a level 1or 2 sleep study?

 

A level 1 sleep study (done in the hospital or a sleep laboratory and is attended by a Sleep Technologist) is the gold standard in the diagnosis of OSA. However, if the patient has no major neuromuscular disease, communication issues or other suspected sleep disorders (e.g. sleep walking or abnormal body movements during sleep), a level 2 study (which monitors the same parameter as a level 1 study but can be done at home and is unattended by a Sleep Technologist) is an option. This allows patients to be tested in the comfort of their own home in their usual sleep environment and likely provides the same accuracy as a level 1 sleep study.

 

 

What if I can’t sleep with so many sensors attached to me?

 

Level 1 & 2 sleep studies involved wearing at least 7 sensors (meaning more wires attached to the patient’s head and body during sleep). Some patients are light sleepers and may not be able to sleep well due to the discomfort from wearing these wires. Hence for such patients, a level 3 or level 4 sleep study may be an option.

 

Level 3 & 4 sleep studies involves less sensors attached to the body and monitor less information during sleep. Hence, it is usually more comfortable and tolerable for most patients. A statistical analysis of data from multiple studies (meta-analysis) have shown that the measurement of AHI (Apnoea-Hypopnoea Index), which is used to assess OSA from a WatchPAT study (Level 3 study), has been shown to match the findings of a full level 1 Sleep Study (~89% of the time). A WatchPAT measures the AHI indirectly by looking at the body’s stress response to choking episodes during sleep (Figure 2).

 

 

Figure 2 – A WatchPAT Study (Level 3 sleep study) which is performed at home and tolerable by most patients

 

A level 3 or 4 sleep study may be suitable for patients who have the following criteria:

 

  1. Have symptoms that are very suggestive of OSA
  2. Do not report any abnormal body movements or sleep walking during sleep
  3. Do not have significant heart or lung conditions that may complicate interpretation of the sleep study
  4. If your doctor does not suspect that you have central sleep apnoea (a condition in which your brain signals to tell your body to breathe during sleep are not working properly)

 

 

Most patients have no problems sleeping with a level 3 or 4 sleep study. However, for light/sensitive sleepers or anxious patients, practicing good sleep hygiene measures will help. These include:

 

  1. Avoiding naps during the day
  2. Avoiding caffeine on the day of the sleep study
  3. Avoiding exercising in the evening of the sleep study

 

 

Sedatives (sleeping pills) are in general discouraged as some may affect the results of the sleep study.

When Should You See An ENT Specialist In Singapore?

  • Any Ear, Nose or Throat symptoms that you are troubled with or concerned of
  • Persistent blocked nose with mouth breathing or snoring

Dr Gan Eng Cern

Dr Gan Eng Cern is a fellowship trained Consultant Ear, Nose & Throat (ENT) Surgeon. He completed his ENT training in Singapore and obtained his subspecialty training in Rhinology and Endoscopic Skull Base Surgery at the world renowned St Paul’s Sinus Centre, University of British Columbia, Vancouver, Canada. He was also a Senior Clinical Lecturer at Yong Loo Lin School of Medicine at the National University of Singapore. Dr Gan was an avid researcher with numerous publications in reputable international ENT journals. He was also an invited speaker and surgical dissection teacher in many ENT conferences and courses.

Awards

  • 2020 – Reader’s Choice Gold Award for Best ENT Specialist
    (Expat Living Singapore)
  • 2016 – Best Educator Award (Eastern Health Alliance)
  • 2016 – “Wow” Award (Patient Compliment)
  • 2014 – Eastern Health Alliance Caring Award – Silver
  • 2014 – 19th Yahya Cohen Memorial Lectureship (awarded by the College
    of Surgeons, Academy of Medicine Singapore for best scientific surgical
    paper)
  • 2012 – Human Manpower Development Award (Ministry of Health,
    Singapore)
  • 2007 – Singhealth Best Doctor Award

Qualifications

  • MBBS - Bachelor of Science, Bachelor of Medicine, Bachelor of Surgery (University of New South Wales, Sydney, Australia)
  • MRCS (Edin) - Member of the Royal College of Surgeons Edinburgh, United Kingdom
  • MMed (ORL) - Master of Medicine in ENT (National University of Singapore)
  • FAMS - Fellow of the Academy of Medicine Singapore

Why Choose Dr Gan Eng Cern

1

Reliable & Reputable ENT Expert

Experienced and patient ENT Specialist who has your best interests at heart. We aim to provide you with accessible and specialized care for any ENT condition in a comfortable setting.

2

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Our friendly staff will assist you to the best of our ability and we are happy to accept most insurance providers and assist with E-filing with relevant insurance providers or Medisave.

3

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Our ENT Specialist, Dr Gan Eng Cern, will be able to diagnose and offer personalised treatments for your specific ENT condition. You can expect a high level of ENT care in a spacious setting with in-house minor surgical, endoscopy, allergy testing and microscopy services.

4

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There are various financial options available for you to ensure that you are able to receive the most optimal treatment and care. Our ENT clinic staff will be able to assist you with your medical insurance claims and work with your chosen healthcare organization to minimize the hassle and paperwork required. In some cases, you may be able to utilise the funds in your Medisave account to defray part of the costs of your treatment. As our clinic is accredited by the Medisave board, we are able to process your claims from your Medisave for certain clinic procedures.

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