Daytime sleepiness. If the question is what are the symptoms of central apnea (csa) vs. What are symptoms of obstructive apnea (osa)... They are essentially the same - daytime fatigue. The physiologic consequences of each lead to different problems but the symptoms may be the same. Best to get a sleep study to determine the nature of the apnea. Patient history and exams rarely accurately predict the presence of apnea.