Does Numbness Of My Mother's Ear Need Immediate Medical Attention?

My mom is 89 and just told me her left ear has been numb off and on for the last week. She has had a recent CT scan and MRI, and we were told she had had some minor strokes in the past but she is in otherwise good health for 89. Should I be worried or should she go to the doctor? It doesn't hurt - just numb.