We are already using vibrations and she can still hear a bit so we can yell. But neither of these is fun in the middle of the night when we're trying to sleep.
YES, SHE HOWLS LOUDER THAN A CAT THAT CAN HEAR.
But not always, sometimes she mutters to herself. We are sure there is a certain amount of dementia as well.
I googled some more last night and there is a vibrating anti-bark collar device for dogs that some have put under the cat's bed (too big for cats) and it activates with barking. So I wonder if a dog e-collar that vibrates, with remote, might help us at night.
I'm also going to look at the DAP diffusers used for dogs. I guess I need a CAP diffuser.
Sigh, we actually have two deaf cats with deaf cat howl. But the other one howls much less frequently and not at night.