A very good point. For anyone not familiar with anterograde amnesia, the classical case is patient H.M. (https://en.wikipedia.org/wiki/Henry_Molaison), whose condition was researched by Brenda Milner.
Or you could have just said "they can't form new memories."
> Near the end of his life, Molaison regularly filled in crossword puzzles.[16] He was able to fill in answers to clues that referred to pre-1953 knowledge. As for post-1953 information, he was able to modify old memories with new informations. For instance, he could add a memory about Jonas Salk by modifying his memory of polio.[2]
That's fascinating!