THE case of Jahi McMath may be the first instance of someone diagnosed as brain dead using accepted criteria and tests, who subsequently demonstrated improvement to a higher level of responsiveness.  She was declared brain dead in December, 2013 and her heart stopped beating in June, 2018.  Her situation and the ethical issues it raises are discussed in detail in a video of a meeting of the Harvard Center for Bioethics.  [see scansx]

https://www.youtube.com/watch?v=tHD0OUUfiR0

Brain Death and the Controversial Case of Jahi McMath