A 78 year-old woman awoke with an inability to voluntarily move the muscles of facial expression in her right lower face. In the clinic, the following signs are noted:
Sensation is intact throughout the entire body and face, movements of the limb and trunk are normal
Movement of the upper face and left lower face are normal She is able to completely close both eyes on request. When she is asked to smile or frown, muscles in the right lower face do not contract. However, when she frowns in response to frustration, muscles in the right lower face contract.
Test results for all CNs other than 7 are normal"
a. Bell's Palsy
b. Facial nerve (CN VII) palsy
c. Stroke affecting the facial cortex
d. Hemifacial spasm