Bartusiak's mother Helen McCole Bartusiak told CNN that her daughter had been suffering from epileptic seizures recently, and her boyfriend found her sitting up in her bed.
"We think she had a seizure and choked and nobody was there," her mother said. "They were working on her for 45 minutes and could not get a heartbeat."
Bartusiak began her career in 1999 at the age of six in The Cider House Rules. She also played the daughter of Michael Douglas' character in 2001's Don't Say a Word.
Her mother said that more recently she had been working on producing and directing her first feature film.