Based on this answer I started thinking about whether or not a Walker's senses will diminish over time. We know that they at least have a sense of sight, hearing and smell, as evidenced S5E01 (and many others besides). What we do not know is how old those Walkers were.
Is there any information that I missed in the show, or from other canon, to indicate whether or not a Walker ever loses any of these senses?
Their powers diminish. So I guess it is safe to assume that their senses diminish as well (like they do in normal humans).
Robert Kirkman mentioned this on Reddit a while ago:
OddGuyOut: In the beginning of the show we saw walkers do things like using a rock to help bash the doors in or turning a door knob, is there a reason we've stopped seeing them do that?
Robert Kirkman: Older zombies are less together and capable of doing things like that. Fresher zombies, which there were more of in season one, are able to do more than older, more rotted zombies.
So, the zombies get weaker as the get 'old' -> most likely their senses get weaker as well.
I would say that yes over time their senses would diminish.
The dead corpse of anyone that dies for any reason will reanimate as a zombie, unless the brain of the individual is badly damaged or destroyed. When a person dies, the infection they carry reactivates critical areas of the brain that support necessary vital systems, resulting in reanimation. Because only a portion of the brain is reactivated, the reanimated person retains only a physical resemblance to their former self.
Because they are rotting, they are destroying some of there nerves that help with the senses, so while their senses would be better than ours, unless they evolve and stop rotting they will loose their senses or part of them.
A zombie "lifetime" varies, though it is know that a human will likely outlive a zombie through the course of many years/decades
Also, their senses are based on a lot more than nerves.
Zombies have the ability to detect scents and differentiate between the living and the dead, and prefer to feed on living flesh. Covering one's self in the scent of decay can act as a camouflage. They can also use sight to distinguish living from the dead, although they seem to have poor eyesight as their irises fade and decay, but they make up for it in very heightened senses of strong hearing and smell.
According to Wikipedia and some medical textbooks pain is considered or 1/2 way considered a sense. And zombies can't feel pain.
Zombies feel no pain.
So while I see no hard evidence I think that it is hinted at through deduction. Theirs brains are flesh and their flesh rots, so even if the body is halfway okay over time sense should diminish.
And if you consider this canon, from the wikia:
As zombies decay, however, their muscles, and consequently their entire body, becomes slowly, but surely, weaker.
And I would say that it would take quite some time.
A reanimated body responds to stimuli such as light, scent, and loud noises. Oddly, even if the head was separated from the body, as long as the brain was intact, the head would still attempt to eat anything within reach.
Unstimulated, zombies stand still or shuffle around rather slowly. When in this state they are referred to as "lurkers," as they can quickly activate and attack and kill.
