Mephisto (cat, 20 yrs. old) had a stroke and is blind and deaf. The other senses are fine--he can smell us when we come in and will scream to signal. He can feel and purrs loudly when we hold him in our laps--which he always wants to do as it is his only sensation. The stroke though has left him wandering in circles and he bumps into things, so he is not feeling space the way that he should as a cat.
Guinness (dog, 13 yrs. old) is deaf in both ears. The ear canal has been removed from one, and the other is so blocked that it too will require removal. He does not wake when we call to him (he never came) but we use hand signals which seem to actually work better, but you must touch him first to get his attention. We have to be careful to touch him gently if coming up on him as he startles.
We have always suspected that his vision and smell were not what they should be, as he would often jump upon encountering things outside, but his hearing was acute. Of course, now he does not go mad when the doorbell rings, or sirens go by outside or Mephisto screams in the night and he sleeps longer, undisturbed.
As a human these losses would be felt acutely as they came (as they are for some of my older relatives). We would know all that we had lost and would never have again. That would add to our sense of loss.
I wonder, do they know what they have lost? Does Mephisto remember seeing and stalking outside? Does Guinness miss when he could hear us call? Did they suffer their own grief upon losing these senses, or feel just a temporary confusion and then readjustment? Do they wish their youth and health back? They are both so thin now for a variety of reasons. Are they aware? Do they see and hear in their dreams? Or, as scientists tell us, are their memories so short that this silence, this darkness seems to be all that has ever been?