Sondra Bianca is an American pianist and pedagogue. She was active from 1930 to 1950, and retired after that. She should still be alive, though in total anonymity. She also performed under different names and recorded on relatively unknown labels. Making her a bit of a mystery.
It seems to me she just didn’t like the stage, and the fame it brought her. Hiding from the public eye under different names was not enough for her, so she just quit. Let’s hope she has been a good teacher.