Answer: frontal
Step-by-step explanation:
Frontal lobe is portion of the brain that helps in regulation and control of congnitive skills such as memorization, speaking languages, solving issues and problems, sharing emotions etc.
According to the case of Phineas Gage, who faced an extreme damage in his frontal lobe of brain when an iron rod cross his skull.He survived from this situation and studies were done on front part of brain in this scenario.
According to the question, Joella's frontal lobe might have got injured when she tripped and fell along on the front side of head.