Because Ronald Reagan was President of the United States and therefore there are hours of recorded speeches, statements and interviews from him, and because he was diagnosed with Alzheimer’s in 1994, doctors can use the information to see if there are early markers for dementia in his use of language; in this case, how one’s vocabulary decreases and use of indefinite pronouns increase.

All this information can be used to help doctors figure out how to diagnose Alzheimer’s and dementia even earlier, perhaps early enough to mitigate it and delay its debilitating effects.

Read the New York Times article about how researchers are parsing Reagan’s words for early signs of Alzheimer’s here.