When I first started having seizures, in my first term at university, I didn't know what they were and as I struggled to describe them, a bit of Antony and Cleopatra kept coming into my head. (I'd done it for A-level so it was burned in there.) It's near the end, where Mark Antony's lost everything. He says he is like a cloud that changes shape with the weather, becoming "indistinct / As water is in water". He tries to explain how he feels: "here I am Antony: / Yet cannot hold this visible shape".
It wasn't much use telling my doctor that I couldn't hold my visible shape. I meant that when I felt the ground vanish, I felt like I was vanishing too. And also, I meant: the seizures were taking me over. I couldn't remember where they ended and I began. Siri Hustvedt explores this in her book about her seizures, The Shaking Woman or a History of my Nerves. I've just reviewed it for Disability Arts Online. It's a pretty amazing book about how illness or disability can take a person over, about how to hold onto a sense of oneself when everything seems to be changing. About what really makes us who we are. The review's here.