Yes it's been used before but rare. First time we see her use her phase power to disrupt bioelectricity of a person is actually back in Excalibur's vol 1 run. I forget the exact issue but Jean & Professor X convinces Kitty to call Peter who's on Asteroid M (this during time Colossus followed Magneto) to trick him to come to Muir Island, something about him being injured and needed treatment or so they believed (thinking his behavior is due to injuries)
As she touches him, she disrupts him just enough that brainwaves can't trigger muscles to move. he's temporally paralyzed.
Another time something similar to this is actually in a What If issue, where instead of Jean, it's Storm who is host to Phoenix force. They find the pod that had the body of real Ororo in it, Kitty phases into the body enough that the nervous systems overlap: Kitty is able to posses Ororo's body and control it.
I can't remember which title or issue. Thought it was Mechanix, but may be X-Men title around similar time frame, Kitty is facing a mob and runs through a person, disrupting the nervous system and making the person faint.