There are also apneas that don't necessarily respond to CPAP/BiPAP treatment. I've been told that I have central sleep apnea -- no effort to breath for up to 30

There are also apneas that don't necessarily respond to CPAP/BiPAP treatment. I've been told that I have central sleep apnea -- no effort to breath for up to 30s at a time -- but BiPAP treatment only made a marginal improvement in number/duration of apneas, and was discontinued as it was aggravating other conditions (skin disorder).