So, you might think your older dog has had a stroke, because s/he has all the symptoms, and they are heartbreaking. And you might cry yourself into a headache, say your goodbyes, and take her into the vet thinking that it's the end.
And then you might find out that she actually has what essentially amounts to dog vertigo, and that she's probably going to recover, and then you spend your weekend feeding her baby food off the tip of your finger and making sure she doesn't try to go down stairs or run into anything.
If something like this should happen, you can now at least recognize the symptoms and not have to cry yourself into a headache and say your goodbyes. You can just get ready to baby the heck out of your dog, which she will probably think she deserves anyway.
Consider yourself informed. :)