what is the theme of the first two paragraph of the story? and the style ?

TRUE! - nervous - very, very dreadfully nervous I had been and am; but why will you say that I am mad? The disease had sharpened my senses - not destroyed - not dulled them. Above all was the sense of hearing acute. I heard all things in the heaven and in the earth. I heard many things in hell. How, then, am I mad? Hearken! and observe how healthily - how calmly I can tell you the whole story.It is impossible to say how first the idea entered my brain; but once conceived, it haunted me day and night. Object there was none. Passion there was none. I loved the old man. He had never wronged me. He had never given me insult. For his gold, I had no desire. I think it was his eye! yes, it was this! He had the eye of a vulture - a pale blue eye, with a film over it. Whenever it fell upon me, my blood ran cold; and so by degrees - very gradually - I made up my mind to take the life of the old man, and thus rid myself of the eye forever.--Edgar Allan Poe, "The Tell-Tale Heart”