I was always taught to use אף אחד with a masculine verb. When would you use it with a feminine verb?
You don't. אף אחד goes only with masc conjugated verb and אף אחת goes with the fem. ones
?אף אחד לא מאבד את הכרה.........ALSO POSSIBLE?..
What is wrong with כלום לא מאבד הכרה ?