For me, my Central Sleep Apnea seems to be tied to neck position. If I sleep with my head forward or leaning to the left, after a while, I will go through cycles of no breathing that last 2 to 3 minutes before my brain recognized the lack of oxygen and starts me breathing again. A couple minutes later, the cycles repeats.

My wife notices this and can connect it to a need for me to nap more during that day. The ability to fall asleep/nap easily during the day is a common symptom of sleep apnea.

We all were envious of my father's ability to take short naps during the day and wake up refreshed after 15 minutes. I believe this ability was due to his apnea. At night, his breathing would slow, getting quieter until it stopped completely. After 2 minutes or so, he would start huffing and puffing until he resumed normal breathing and repeat the cycle.

And keg, If you have sleep apnea, HBOT would provide quite an invigorating oxygenation to your brain that would decrease as you O2 levels returned to normal then decreased after the next apnea episode. Oxygen debt leaves the brain in a depleted state until oxygen levels can brought back to normal.

There are some researchers who believe concussion damages the capillaries that are where oxygen transfers to the neurons, etc.