Sitting in her wheelchair, head bowed toward her lap, Marta Cinta González Saldaña motions for the music to be turned up. As the opening notes of Tchaikovsky’s Swan Lake swell, the then 90-something-year-old with dementia lifts her hands. When the song reaches its dramatic peak, she presses her palms in opposite directions away from her body, lifting her face to the sky, with all the grace of the ballerina she once was.