Doctor discusses sleep apnea diagnosis

Apnea is a common, and potentially deadly, form of sleep disordered breathing. Dr. Bertrand De Silva discussed the stages of sleep and how apnea is diagnosed, during a session of the Airway Focused Dentistry Mini-Residency. The course was co-developed by Dana Point dentist, Dr. Mark A. Cruz.

The sleep cycle

Sleep is not a single a state. It is composed of four distinct stages.

• Stage one – If you think you might have dozed off at your computer, you probably entered stage one sleep.
• Stage two – When there is no denying that you fell asleep at your desk, you likely reached stage two.
• Delta – When you are home in bed and slip into sound sleep, you have probably reached the delta phase.
• Dream – The final stage of sleep is characterized
  by stillness of body, rapid eyeball movements, and dreaming. This is the
  time when the brain processes information and experiences of the day,
  committing important data to memory.

Sleep studies

To diagnose apnea, physicians use a comprehensive sleep study, which measures many different metrics simultaneously. These include:

• Brain activity
• Eye movement
• Muscle tone
• Heart rate leg movement
• Respiratory pattern
• Chest movement
• Abdominal movement
• Oxygen saturation
• Body position

Dr. De Silva reviewed slides containing compressed data from various patients’ sleep studies. He showed that interruptions in breathing clearly co-related with changes in brain waves, showing that the individual had awoken. These are apneic events.

In one sleep study, the patient experienced multiple apneic events every few minutes, causing him to wake up before reaching delta or dream phases of sleep. Only when he was put on a CPAP machine, which prevents apneic events, did he progress to deeper stages of sleep.

Dr. Cruz, Dr. De Silva, and their colleagues are working to promote greater education and awareness of obstructive sleep apnea syndrome.