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Frequently Asked Questions

Who is eligible to participate in the Brain Changes in Sleep Apnea Study (BCSAS)?

Patients of the Sunnybrook sleep clinic with newly diagnosed sleep apnea of sufficient severity may be eligible to participate in the BCSAS. Eligible participants must be newly diagnosed with sufficiently severe sleep apnea but not yet receiving any treatment for it. Eligible participants must be planning to start CPAP treatment for sleep apnea.

Who is not eligible to participate in the study?

Individuals meeting any of the following criteria will not be able to participate in the BCSAS:
  • Known history of stroke, transient ischemic attack or other neurological diseases
  • Severe lung or heart diseases, including chronic obstructive pulmonary disease or congestive heart failure
  • Persistent irregular heart rhythm
  • Use of alpha-blocking medications, which are sometimes used for high blood pressure or to treat prostate disease
  • Unable to undergo MRI safely (see Question #3)
  • History of panic disorder

What conditions make it unsafe to undergo an MRI?

Research staff will conduct a brief interview with all potential participants to see if they can undergo an MRI safely. Individuals meeting any of the following criteria may not be able to undergo an MRI:
  • Intracranial metal aneurysm clip
  • Implanted electric or electronic device such as a heart pacemaker, defibrillator, insulin pump, implanted hearing aid, neurostimulator, etc.
  • Coronary artery stent, prosthetic heart valve and annuloplasty ring, pulmonary artery catheter
  • Joint replacement (e.g., hip, knee, etc.) or any type of prosthesis
  • Metallic fragment or foreign body in the eye
  • Claustrophobia or panic disorder
  • Currently pregnant or breastfeeding
  • Permanent contraceptive device
  • Breast tissue expander
  • Tattoo, permanent makeup or body-piercing jewellery

Am I eligible to participate if I was diagnosed with sleep apnea at a hospital or clinic other than Sunnybrook?

No, unfortunately you will not be eligible to participate. To be eligible for our study, you must have been diagnosed with sleep apnea at Sunnybrook and be a patient of the Sunnybrook sleep clinic.

Am I eligible to participate if I use prescribed or over-the-counter sleep aids to help me sleep?

Yes, individuals who use prescribed or over-the-counter sleep aids are still eligible to participate in the study.

How many people will participate in the study?

It is anticipated that 80 people will participate in this study—40 patients from Sunnybrook and 40 from sleep clinics at the University of Edinburgh in Scotland.

How do I participate in the study?

If you would like to participate in the BCSAS, then please contact the study coordinator by phone (416-480-5143), email (, or through the Contact Us section of the website. He can answer any questions or concerns that you may have before, during or after your participation in the study.

Why is participation in the study important?

If you decide to participate in the BCSAS, you will be helping us further our understanding of the impact of sleep apnea on brain function and brain diseases like stroke, dementia and Alzheimer’s disease. The results of this study may lead to new treatments, in addition to CPAP, that can prevent or reverse the brain damage caused by sleep apnea.

How will participating in the study benefit me?

You will not benefit directly from participating in this study. The physical measurements collected by the BCSAS are only for research purposes. This means that the physical measurements are not diagnostic and are not designed to replace routine clinical care. That being said, at the end of your participation in this study, we will mail you summaries of the sleep, blood pressure and breathing measurements you recorded at home.

Will I be paid to participate in the study?

No, you will not be paid to participate. However, you will be reimbursed for travel and parking on the days you come to Sunnybrook for study visits.

Are there any risks involved in participating in the study?

There are no medical risks to you from participating in this study. However, you may experience side effects from participating in this study.

There may be some minimal discomfort from wearing the wristwatch-like accelerometer. You may also experience some minor disturbance of your usual sleep on the nights that you are wearing the WatchPAT device and/or the portable blood pressure monitor. Blood collection can sometimes cause bruising, pain or, very rarely, loss of consciousness.

There is no significant risk of harm to you during the MRI scan. Rarely, some participants may experience a temporary and mild tingling sensation during the MRI. You may also experience temporary stress or anxiety from the MRI. During a few minutes while in the MRI scanner, you will breathe a carbon dioxide mixture through a special mask. Rarely, this may cause discomfort in breathing, high blood pressure or an anxiety attack.

The MRI and other tests may reveal something about your brain that you were unaware of, which could cause some anxiety or discomfort. If there is a significant medical problem identified, then appropriate care will be arranged for you. Some minor findings in MRI scans will not be described to you as they are of no known clinical consequence.

How will my information be kept confidential?

If you decide to participate in the BCSAS, then the only individuals who will have access to your personal information are the staff involved in the study. The investigators and study staff will look at the health information and sleep study results collected as part of your clinical care in the Sunnybrook sleep clinic. Access to your personal health information will take place under the supervision of the principal investigator of this study.

Data in the BCSAS database at Sunnybrook may be shared with outside researchers who pass a strict scientific and ethical review, but all identifying personal information will be removed prior to this shared access. Therefore, they will have no way of identifying who you are.

Furthermore, when the results of the study are published, your personal identity will not be disclosed. The published results will only refer to the study population as a whole.

Can the results from the study substitute for a visit to my doctor?

No, the results from this study are not meant to diagnose or treat individuals.

What happens if I agree to the study and then decide I no longer want to participate?

We understand if you decide, for any reason, not to start or complete your participation in the study. However, please inform us as soon as possible via phone (416-480-5143) or email ( if you decide to withdraw from the study. If you still have study devices with you, then we will ask you to return the equipment to Sunnybrook.

Contact information

Telephone: 416-480-5143
Address: Sunnybrook Health Sciences Centre, 2075 Bayview Ave., M1 600, Toronto, ON M4N 3M5