While sleep apnea is often used to refer to obstructive sleep apnea, they are not the same condition, as there are two different types of sleep apnea. In addition to obstructive sleep apnea, another type of sleep apnea is known as central sleep apnea (CSA), which is far less common than OSA. The difference between the two types of sleep apnea is that CSA is a neurological disorder, meaning that the problem lies within the central nervous system, while OSA is more of a mechanical problem dealing with the actual airway itself.