How did Beethoven go deaf?

The cause of Beethoven’s deafness is generally thought to have been Otosclerosis – is a disease, which results in new bone formation either in the area of the stapes bone or in the cochlea housing the hearing nerve; or it can be a combination of both. When the bony deposits infiltrate the stapes bone, this bone is unable to vibrate and p the sound into the inner ear. This results in what is called a conductive hearing loss, i.e., the sound is not being properly “conducted” into the inner ear. As a general rule, the thicker the bony deposit the greater the hearing loss, and the longer the hearing loss, the greater is the amount of deposits. The fixation of the stapes usually follows a slow and relentless course with progressively worsening hearing.