Carly Simon in Vineyard Haven, Mass., June 4, 2018. The singer and songwriter has been diagnosed with Parkinson’s disease, she announced on Monday, July 27, 2026. (Elizabeth Cecil/The New York Times) By DERRICK BRYSON TAYLOR Singer and songwriter Carly Simon has been diagnosed with Parkinson’s disease, she announced earlier this week. “It has taken me some time to understand the diagnosis, to adjust to it and to decide how much I wanted to say about it,” Simon, 83, said in a statement, adding…