Brooke Astor's son is back at his Manhattan trial, a day after he fell and hit his head in a courthouse restroom.

Anthony Marshall, who's 85, had heart surgery last fall. He takes blood thinners and walks unsteadily with a cane. He also has reportedly suffered a mild stroke.

Marshall denies charges that he exploited his mother's dementia to loot her $198 million fortune.

On Thursday, a prosecution witness waited to resume her testimony as lawyers held a conference with the judge.

Pearline Noble of the Bronx was Astor's nursing assistant. She started working for the philanthropist in mid-2003, helping her with grooming and other personal tasks.