what is the central idea about the narrator of "the tell-tale heart?" does edgar allen poe intend readers to infer based on what he does, says, and what he doesn't say

The central idea of the narrator of 'The Tell-Tale Heart' is the effects of guilt or conscience and the descent into madness. In the story, the narrator's sanity is definitely in question. He kills the old man because of his "evil eye" but then feels guilty about it.