Patient Problem Three
The clinician needs to differentiate an upper motor neuron lesion (UMNL) from a lower motor neuron lesion (LMNL) affecting motor innervation to the patient's face (i.e., Bell's Palsy or brainstem lesion). My examination scheme would include the following:

• Check for UMNL signs (i.e., paresis, tremor, and spasticity)
• Test CN VII
• It is important to determine if additional cranial nerves are involved, as this could indicate a vascular problem in the brainstem
• Note whether the patient can wrinkle his forehead. UMNLs will maintain some function of the frontalis muscle.
• Note whether there is sensory involvement of the face by examining CN VI sensory and CN V corneal reflexes

If motor and sensory were interrupted to the face, then corticospinal and corticobulbar fibers have been interrupted. This would interfere with voluntary control of the left face and perhaps the body. The sensory information from the left side of the face is not reaching consciousness, therefore, the lesion is in the right internal capsule and is focal and non-progressive. Lastly, the abrupt onset of the patient’s condition can indicate a vascular etiology, such as a stroke.

Patient Problem Four
Since the diplopia is relieved by closing either eye, the most likely etiology is ocular motor (i.e., test CN III, IV, and VI). The clinician will also need to differentiate UMN and LMN dysfunction through a careful history and physical examination, as an early symptom of multiple sclerosis is diplopia.