I fostered Snowball (CCG) when she had her two kittens - all white - and became suspicious when one of the kittens liked to sit on the vacuum while I cleaned their room, sure enough he was deaf. I tested it by ringing a metal bell right behind him and he didn't show any reaction. Luckily the new owners still wanted him and he went, with his sister to a good forever home. One of my own cats, Pepper, had a very serious accident at 9 months old (we believe someone kicked him and destroyed his hip joint) and couldn't clean himself properly so we vacuumed him as he lay on the sofa - he loved it and so we did it for the rest of his life.