[apneaboy]

'Vertigo, unrelated to ear drum failure, is one you don't hear much about, but it happened to me, only once. Diving a Florida Spring, super clear water and deep. I was about 10 feet down and got an instant, very strong sense of vertigo, had no idea which way was up even though I could see it clearly. Only lasted a few seconds, but was EXTREMELY uncomfortable. The only extenuating circumstance I could think of was lack of a hood, but I'd been in for quite a while, so it shouldn't have had any effect.

Connor'

It could have possibly been hyperbaric vertigo. If one ear equalises at slightly different rates to the other you can get the vertigo feeling. Weird sensation. It can happen at the beginning of a session or even near the end once your ears 'get a bit tired' or maybe a bit of stuff (mucus, blood etc) is floating around inside causes a blockage that wasn't there before.

Its doesn't have to be a rupture as such.