A Rochester lab may have uncovered why Beethoven experienced deafness (2024)

ROCHESTER — Mayo Clinic in Rochester receives tens of thousands of biomedical samples each day for analysis. In one of the three labs that Paul Jannetto oversees, the Metals Laboratory, the meat-and-potatoes work in that lab includes testing patients' samples for heavy metal toxicity and trace metals. The lab also processes 90,000 kidney stones each year to see what each one is made up of.

But, a few months ago, two unusual specimens arrived at the Metals Laboratory: locks of the German composer Ludwig van Beethoven's hair.

"They always say, 'Opportunity knocks; you only need to answer the door," said Jannetto, the Metals Laboratory director and professor in Mayo Clinic's Department of Laboratory Medicine and Pathology.

Kevin Brown, who owns the hair that has been verified as Beethoven's, wanted to test the hair for heavy metal toxicity. Beethoven had struggled with gastrointestinal issues, kidney and liver disease and deafness in his life, and in a letter to his brothers, Beethoven asked, upon his death, to have his doctor "describe my malady." It had been speculated, Jannetto said, that exposure to lead could have contributed to Beethoven's health issues.

"He really wanted to understand what caused some of his ailments that plagued him," Jannetto said.

Brown and another collaborator, William Meredith, reached out to Nader Rifai, a pathology professor at Harvard Medical School, who recommended sending the hair to Mayo Clinic's Metals Lab to measure how much lead was in the hair.

"It's more of a highly specialized laboratory; it's actually one of the top five metals laboratories in the world," Jannetto said. "Our predominant testing falls under heavy metal toxicity — lead, arsenic, mercury — as well as trace element analysis."

To test the locks of hair — which were both collected in the final years of Beethoven's life — Jannetto's team washed and dried the locks, took 10 milligrams of hair from each lock, digested the samples in nitric acid and used a mass spectrometer to measure how much lead was present. The answer: Beethoven had 64 to 95 times the amount of lead in his hair than would be found in a modern person's hair who had no exposure to lead. He also had elevated levels of mercury and arsenic in his hair.

Contributed / Mayo Clinic

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"We had 258 micrograms of lead per gram of hair in the Bermann Lock, and around 380 micrograms of lead per gram of hair in the Halm-Thayer Lock," Jannetto said. "In an unexposed individual, our reference range is less than 4 micrograms of lead per gram of hair."

Because hair is connected to the bloodstream at the root and grows at a rate of half an inch per month, Jannetto said the lead found in Beethoven's hair could indicate chronic exposure to lead rather than "an acute poisoning or event."

Lead was used in many applications during Beethoven's life, Jannetto said, especially medicine — certain medications contained lead, and bandages were soaked in lead salt to disinfect wounds. Beethoven also could have been exposed to lead through drinking wine, too.

"Sometimes back then, lead acetate was purposefully added to wine because it binds the acid, the vinegar; it does make a sweeter tasting wine," Jannetto said.

Jannetto and his research partners published their work in the journal Clinical Chemistry this month and wrote that the concentration of lead in Beethoven's hair, and the estimated amount of lead that would have been in his blood, "are commonly associated with gastrointestinal and renal ailments and decreased hearing but are not considered high enough to be the sole cause of death."

Though Beethoven died nearly 200 years ago and the dangers of lead are now well-known, Jannetto said this research is important not only to investigate why Beethoven went deaf, but to also raise awareness of lead exposure today.

"Even today, we still have issues with lead plumbing," Jannetto said. "There is no safe level of lead. We know that, particularly in young children, (it) can cause brain damage and neurological consequences and decreased IQ and lots of health issues, and so really having awareness about lead and the sources and exposure and how to prevent that and the importance of testing so you can identify the source, remove them from the source and prevent some of this toxicity."