The radiation to my head (daily for seven weeks) permanently screwed up my sinuses. I have difficulty breathing at night (like a perpetual head cold) and though vastly improved, there was a long intervel where the only way I could get a complerte night's sleep was with the ZG chair.
I still have it folded up in a down comforter in our bedroom for emergencies, but have not needed it in quite a while. For about $75, it provided what a $2000 bed could not for a good night's sleep.
Thankful to have found that solution.