This explains why Leonardo da Vinci could not finish even the painting "Mona Lisa"!

Leonardo da Vinci, a figure of rebirth, was known to be able to use both hands alike. The analysis of his drawings, his writings and paintings revealed that he wrote with his left hand but never painted with it.

But many scholars have assumed that during the last years of his life, he suffered a paralysis in his right hand, a weakness on one side of the body, possibly caused by a stroke. Other studies also suggested that it could suffer from Dupuytren's disease, where the tissue on the skin thickens and narrows. According to a study conducted by Dr.David Lazzeri, specialist of plastic surgery and Carlo Rossi, a neurologist specialist, said Leonardo da Vinci suffered uninterrupted nervous damage in his right hand, which improved his skills artistic. They analyzed a sketch of Leonardo da Vinci, which was made of red chalk by Giovanni Ambrogio Figino and compared it to a Leonardos engraving. But in this outline, Leonard's right hand is not in the tight position associated with muscular spasticity after a stroke. Instead, his hand and finger are bent, the researchers said. This may explain why he did not finish many paintings during the last five years of his life, including Mona Lisa.