Ley1 still inexplicably and evasively ignores my point that patients with the Ondine curse do not feel distressed while actually suffocating. He simply confuses the matter by gratuitously suggesting that an alarm system has to be either off or maximally on. Clearly many physiological alarm systems produce mounting discomfort and activation but do not lead to a full-fledged maximum reaction unless adaptive action has failed to be effective. Ley obscures the issue by a physiologically unwarranted dictum about how alarm systems work.
Central sleep apnea is a pathological feature of the breathing control mechanism; patients with central sleep apnea breathe insufficiently except during full wakefulness. Such patients are quite similar to patients with the Ondine curse, so this does not contradict my views. In obstructive sleep apnea, obesity or upper airway narrowing may result in hypoxia and hypercapnia, which may induce central apnea. During sleep apnea, the usual response
Klein DF. The Ondine Curse, False Suffocation Alarms, Trait-State Suffocation Fear, and Dyspnea-Suffocation Fear in Panic Attacks-Reply. Arch Gen Psychiatry. 1997;54(7):678. doi:10.1001/archpsyc.1997.01830190106013