What are the two types of sleep apnea, and what are the characteristics of each disorder?

The two types of sleep apnea are obstructive sleep apnea and central sleep apnea:

Obstructive sleep apnea is characterized by occlusion of a structure such as the posterior anterior wall of the brain, which causes individuals to stop breathing during deep sleep. This form of apnea may be life threatening, because it can cause a dangerous level of cardiac stress. Obstructive sleep apnea may also result in sleep deprivation, as the person is unable to get a full and restorative night's sleep.

Central sleep apnea may explain the reason why some people die in their sleep. In experiments on rats, cell damage within the brainstem (pre-Botzinger-complex neurons) resulting from neurodegenerative diseases, causes rats to stop breathing entirely during rapid eye movement (REM) sleep.