In late March 1827, Beethoven's lifeless corpse lay in an oak coffin in his home in Vienna. His face was grey and misshapen after an autopsy that morning by Drs Johannes Wagner and Andreas Wawruch. They had removed the temporal bone which lies in the skull just behind the jaw. Crucially, they also took out his middle ear bones, but for some reason, didn't think to describe what they found, or even to keep them for later examination.
It was an infuriating omission, because we'll never know for certain what caused Beethoven's deafness. Infuriating for us, but also for the medical profession, so 36 years after his death, they opened his tomb to have another look. They found nothing and then 24 years later, they tried again, but still with no result.
Beethoven is now thought to have suffered from otosclerosis, a thickening of the three middle ear bones that prevents their movement. One day we may find Beethoven's ear bones in a dusty jar, but until then otosclerosis is a good theory
If he were tested today, his audiogram might show a pronounced dip around 2000 Hz known as ''Carhart's Notch''. That's the telltale pitch at the resonant frequency of the middle ear bones that suggest they have become fixed due to calcification.
In 1797 Beethoven noticed he was starting to miss words during conversation, and his ears were ringing with incessant tinnitus. In 1801 he wrote to his friend Franz Wegeler, complaining "For the last three years my hearing has become weaker and weaker. The trouble is supposed to have been caused by the condition of my abdomen...''
Beethoven was an eccentric, wayward individual who did not care much for social convention. He let his hair grow into a great untidy tassel and could be seen wearing unwashed clothes. With his hearing so bad, he'd press his forehead against the piano, trying to listen to the notes. As he did this, sound would be conducted directly through his skull, bypassing his middle ear and going directly into his cochlear.
As his hearing deteriorated, he couldn't hear the top notes of the orchestra, which appears to have affected his composition. Between 1797 and 1798, his early string quartets comprised about eight per cent high notes. By 1805, he was having trouble hearing woodwinds, and his opus 59 has about five per cent high notes. By the time of his late string quartets, high-pitch notes were down to four per cent. The evidence is not conclusive, but it seems likely this was due to his declining hearing.