There are many causes of facial paralysis, and facial paralysis occurs when there is loss of facial movement. Facial paralysis may be unilateral (affecting one side of the face) or bilateral (affecting both sides) and may affect people of all ages. Paralysis may involve the entire face or only a portion of it.

Are There Tests Involved?

Certain tests are sometimes helpful in diagnosing the cause of facial paralysis or predicting whether it will improve. The role for testing varies on an individual basis.

  • Electroneurography (ENOG): ENOG records a muscle signal after maximal stimulus of the facial nerve near the base of the ear. ENOG is useful early after the onset of facial paralysis to predict which patients will have poor recovery of facial movement.
  • Electromyography (EMG): EMG may be useful in determining the extent of nerve injury and the potential for spontaneous recovery. EMG may also be used to identify appropriate donor nerves in cases of multi-nerve dysfunction. EMG is most useful after 3 months from the time of onset of facial paralysis.
  • Magnetic Resonance Imaging (MRI): Imaging studies may be indicated to visualize the path of the facial nerve in some cases.