What does Roderick say is causing the sounds in the house?

Roderick believes that Madeline is causing the sounds in the house.

“Not hear it? — yes, I hear it, and have heard it. Long — long — long — many minutes, many hours, many days, have I heard it — yet I dared not — oh, pity me, miserable wretch that I am! — I dared not — I dared not speak! We have put her living in the tomb! Said I not that my senses were acute? I now tell you that I heard her first feeble movements in the hollow coffin. I heard them — many, many days ago — yet I dared not — I dared not speak! And now — to-night — Ethelred — ha! ha! — the breaking of the hermit’s door, and the death-cry of the dragon, and the clangor of the shield — say, rather, the rending of the coffin, and the grating of the iron hinges, and her struggles within the coppered archway of the vault! Oh whither shall I fly? Will she not be here anon? Is she not hurrying to upbraid me for my haste? Have I not heard her footsteps on the stair? Do I not distinguish that heavy and horrible beating of her heart? Madman!” — here he sprung violently to his feet, and shrieked out his syllables, as if in the effort he were giving up his soul — “Madman! I tell you that she now stands without the door! “

How does the narrator describe the disease affecting Madeline put the following in your own words