Doc: Three types of sleep apnea explained
Dear Dr. Roach: I am a pretty healthy 53-year-old female and have central sleep apnea, along with a few obstructive events. I see a neurologist for this, and he doesn’t seem concerned with finding out why I have the central events.
I should mention that I use a BiPAP nightly, and my apneas average 10-12 per night. All I have read about CSA online indicates an underlying cause, like stroke, heart problems, Parkinson’s disease (which my dad had) or Alzheimer’s disease. Is central apnea a precursor to one of these conditions? I worry constantly! Should I push to find answers?
Dear R.A.: Sleep apnea is a condition where people stop breathing for a period of time during sleep. It comes in three types. By far the most common is obstructive sleep apnea, in which the muscles controlling the soft palate become relaxed, so the airway closes. A partial closure is what causes snoring, a major risk factor for OSA. Obesity is another major risk factor, but some people who are not obese have neck anatomy that predisposes them to OSA. In OSA, the airway is completely closed, so the negative pressure from the lungs closes the airway even more tightly. As the oxygen level goes down and carbon dioxide levels rise, sensors in the brain cause the person to wake up, which causes the muscles in the airway to open enough to get a few good breaths, “silencing” the alarm. In very severe disease, this apnea event may happen hundreds of times in a night, without the person ever being aware.
In central sleep apnea (“central” meaning the brain), the problem is with the alarm sensors themselves or in the parts of the brain that regulate breathing. Severe heart failure and several brain problems, especially the ones you mention, often are the underlying cause, but sometimes no cause is found. When it is associated with one of these causes, it’s usually with a well-established problem, rather than being the first sign.
Some people have both obstructive and central events, leading to the term “mixed” or “complex’”sleep apnea. This probably is more common than recognized, and is likely what you have. In some people, the central events are related to the CPAP (continuous positive airway pressure, which essentially uses air pressure to keep the airway open) or BiPAP (bilevel positive airway pressure, where the airway pressure is higher in inhalation than exhalation).
I suspect you have a mixed sleep apnea syndrome, and I think it is unlikely to herald the onset of disease.
Dr. Roach writes: A recent column on a severe case of blepharospasm (eye twitching) generated some helpful letters from readers. I had readers tell me they had been cured by making sure their glasses were prescribed correctly; with magnesium supplements; and with vitamin B-12 supplements for an unrecognized B-12 deficiency.
I did not find these in my reading about this problem, but blepharospasm can be extremely uncomfortable to live with, and it is easy to check for B-12 and magnesium deficiency and to ensure that the eye is correctly refracted. As always, I appreciate helpful suggestions from my readers.
Email questions to ToYourGoodHealth@med.cornell.edu.