An analysis of skull fragments from German composer Ludwig van Beethoven confirms that he suffered from lead poisoning for many years, a possible cause for his dour demeanor, researchers said Thursday.

"Beethoven had hoped that some day it would be revealed why he acted the way he did," said Paul Kaufmann, the owner of the skull fragments, who loaned them to the Ira F. Brilliant Center for Beethoven Studies at San Jose State University.

"He was seen as angry and uncooperative at times. This finding helps shed some light on that," he said. "Now we know that this was the reason for his suffering."

Lead poisoning can lead to headaches, fatigue, concentration problems and other health issues.

Analysis in the late 1990s from a lock of Beethoven's hair indicated that he had lead poisoning at the time of his death, but the latest skull analysis revealed that the condition existed over a long period of time.

"You can't draw any conclusions from the hair sample. This is a more significant finding," Beethoven scholar and biographer Maynard Solomon, who was not involved in the skull testing, said in a telephone interview.