Alex Klein is one of the world’s best oboists. He’s principal of the Chicago Symphony. But three years ago he was diagnosed with “focal dystonia, a neurological disorder in which the brain, for unknown reasons, sends messages through the nerves that cause muscles in a certain part of the body to contract and curl up involuntarily. The disease is usually painless, and the contractions occur only during specific tasks. For instance, the third and fourth fingers on Klein’s left hand might fail him in a Mozart concerto, but they work perfectly when he ties his shoes or uses his left hand for other fine motor tasks.” After going through 30 doctors, Klein is resigning from the CSO.