One of the most important things we can do as pet owners is to be continually vigilant. Our cat's behaviors may become as commonplace as the carpeting, but they shouldn't be. Our awareness needs to be consistent, every single day, especially with an older animal in the home.
Older cats can have troubles with hearing, eye sight, and balance among so many older things. Like their human counterparts, these changes reflect their advancing age. But sometimes these lifestyle changes come along quickly. This can cause behavioral changes that are subtle. If we're being aware as pet parents, we can catch the changes.
Take Maui, for instance. She's deaf. How do we compensate for her deafness? We gently pat her to wake her up for food and we flick the light switches so we don't startle her. We also tap our hands on the floor when we want her to come to us. The whole family makes an effort not to scare her but rather engage her in different ways since she can't hear us. Yes, we still talk to her constantly and she sometimes talks back. More than anything, Maui needs to be engaged in her silent world.
It wasn't difficult to figure out what worked the best. We just found ways to communicate with her. She still is very vocal although we've noticed that her volume control seems to be broken :) She meows very loudly now whereas she never did before. Of course, she's talking to us. What we've found is that she says "jump" and we don't even ask how high. We just do!