Sleep Studies

There are two main types of sleep study available at Centurion - the home-based sleep study and the in-lab sleep study. Depending on a patient's eligibility and situation, doctors may recommend one or the other.

Home-Based Sleep Study

What does this test involve?

Patients attend one of our clinics where a sleep technician will attach small sensors and electrodes to the head, chest, finger and legs to record biological signals during sleep. This is a non-invasive test which measures brain wave activity, breathing, snoring, heart rate and oxygen levels, as well as body positioning and movement. Patients take the device home to sleep with and return it the following morning for analysis.

Depending on the specific requests made by the referring doctor, any of the following sensors may be applied:

• Head: Electrodes are placed near the eyes, behind the ears, on the head, on the forehead and under the chin 
• Nose: A Nasal/Oral Cannula is placed below the nostrils
• Effort Bands are placed around the chest and abdomen
• Leg sensors are placed below the knees 
• An Oximeter will be placed on one finger to measure oxygen saturation in the blood 

You can download an information sheet which will tell you what to expect on the night, and show you a picture of what the study will look like.

Who is this test suitable for?

Although there are currently no published guidelines by Australian authorities, the American Academy of Sleep Medicine (AASM) has published suggested guidelines for the use of ambulatory sleep studies in the diagnosis of obstructive sleep apnoea (OSA). They recommend that ambulatory sleep studies be used only in the context of a comprehensive sleep evaluation and for the following patients:

• Patients with a high pre-test probability of moderate to severe OSA. 
• Patients with no significant co-morbid medical condition. Examples of co-morbid conditions include moderate-severe pulmonary diseases (cystic fibrosis, pulmonary fibrosis, active asthma, COPD), congestive heart failure and neuromuscular diseases (ALS, multiple sclerosis, Parkinson’s disease).
• Patients suspected of having no co-morbid sleep disorder other than OSA. 
• Patients unable to undergo a PSG.
• To monitor response to non-CPAP treatments after the diagnosis has already been made. 
• The AASM recommended that ambulatory sleep studies are not appropriate for general screening of asymptomatic patients.

What is the process for booking an appointment?

A Home Based Sleep study can be referred directly by a GP. We ask that you submit your referral before booking your sleep study. We also ask that you complete additional forms to assist us in arranging your appointment. You can find a copy of all required forms here. Please submit the forms by email, fax or in person at one of our clinics. After these forms are received, we can proceed with the booking process.

What preparation is required for this type of study?

For any sleep study, patients should eat prior to coming in, as well as removing any make-up and jewellery (including rings and watches). In particular, nail polish must be removed prior to the appointment. For home based sleep studies, it is also recommended that patients arrive at their appointment wearing loose comfortable clothing that would be suitable for sleep. Ideally a loose, button down pyjama shirt could be worn, but failing this, a loose shirt with a wide collar is workable. Patients may choose to sleep shirtless if they choose, but a jacket or loose shirt is recommended for use on the journey home. Of particular note, it will not be possible for patients to change their shirts after the appointment. If patients are especially careful, they may be able to drive themselves home following the procedure, however, it is recommended that patients should arrange to be driven home by a friend or family member. Alternatively a taxi can be arranged if required. Patients should not take public transport home for a sleep study.

What happens after the study?

When a patient wakes on the following morning, you can remove the sleep study machine yourself. This is process is very straightforward, and will be explained to you by the technician on the night of your study. Patients are requested to return their units to the clinic where they picked it up by 10 am on the day following the study, or at another time or location if agreed upon in advance. The analysis and report generation process will then require approximately 2-3 weeks. If results are required urgently, please inform reception when making an appointment, it may be possible to fast-track analysis for urgent cases. Results will be sent to the referring physician with whom an appointment can be made for the results.

In-lab Sleep Study

What does this test involve?

Sleep tests are non-invasive, pain-free procedures conducted to observe what the body does during sleep and to determine the cause of sleep problems. In-lab sleep studies are frequently used by sleep specialists to diagnose a wide range of sleep disorders, including sleep apnoea, movement disorders and neurological problems such as narcolepsy.  Depending on the kind of in-lab sleep study, a sleep technician will attach small sensors and electrodes to the head, chest, finger and legs to record biological signals during sleep, including brain wave activity, breathing, snoring, heart rate and oxygen levels, as well as body movement and positioning.  The sleep technician will be in attendance throughout the entirety of the study, and will correct any problems that may occur. 

What types of in-lab sleep studies are there?

Unlike a home-based sleep study, there are multiple different kinds of in-lab sleep studies, depending on the suspected diagnosis, which will be determined by a sleep physician.  The most common types of in-lab sleep studies are listed below.

• Diagnostic Polysomnogram (PSG) – this is the “gold standard” for sleep studies and requires spending a night at a sleep clinic. During the PSG, a sleep technician records multiple biological functions during sleep, such as brain wave activity, eye movement, oxygen and carbon dioxide blood levels, heart rhythm, breathing rate, airflow, snoring, and body movement via electrodes and monitors placed on the head, chest and legs.
• CPAP Titration Study – CPAP stands for “continuous positive airway pressure” and is a non-invasive and non-surgical treatment for sleep apnoea. The patient is fitted with a small mask, which is hooked up to a CPAP unit, which delivers an air pressure through the mask into the airway to keep the airway open during sleep. During the course of the study, pressure is adjusted (titrated) to keep the airway open and to ensure the patient is apnoea-free in all stages of sleep and in all body positions.
• Multiple Sleep Latency Test (MSLT) – this test measures excessive daytime sleepiness by recording how long it takes a patient to fall asleep. Patients are given several opportunities to fall asleep during the course of the day when they would normally be awake. For each opportunity, time to fall asleep is measured. It is used to rule out certain sleep disorders. 
• Maintenance of Wakefulness Test (MWT) – this test measures a patient’s ability to stay awake and consists of a series of 40-minute trials, during which the patient tries to stay awake.

What is the process for booking an appointment?

An in-lab sleep study requires a referral from a specialist. There are a number of specialists at Centurion who can provide a referral if required. A referral form can be found here for external physicians to fill out. Patients can send a completed copy of the referral by email, fax or by coming into one of our clinics. Patients will be offered the next available physician appointment upon receipt of the referral.

What preparation is required for this type of study?

For any sleep study, patients should eat prior to coming in, as well as removing any make-up and jewellery (including rings and watches). In particular, nail polish must be removed prior to the appointment. For an in-lab sleep study, patients should bring their pyjamas, as well as shampoo, soap and a towel in case they would like to shower in the morning. Patients may make whatever arrangements are suitable for transport to and from the appointment. Questions regarding parking at each of our clinics should be directed to reception while booking the appointment. A taxi may be arranged in the morning if required.

What happens after the study?

The analysis and report generation process requires approximately 2-3 weeks. Results are sent to the referring physician.