She didn't want to be reminded of the fact that there could be a correlation between her memory issues and her past head injuries. Like a Muggle athlete, she could be experiencing the side effects of a violently lived life. One more blow to the head might make it all even worse. She'd been reluctant to allow the Healers in charge of her care to scan her brain for any noticeable damage. There was a knot in her stomach the entire time as they looked for any potential internal wounds. Why she was afraid she wasn't sure. Maybe because she knew it was easier to pretend there was nothing wrong than it was to know there was.