Bell’s Palsy Tests and Diagnosis

Medical History

The unknown cause of facial paralysis or weakness on one side of a patient’s face is the most obvious symptom of Bell’s palsy. A person with this condition may also complain about other symptoms like drooling, hearing loss, impairment of taste, change in facial appearance, difficulty drinking and eating, changes in the amount of tears and saliva, tearing, and headache. There may be some patients who complain about influenza, mild cold or other upper respiratory tract infection within a week before the manifestation of Bell’s palsy. A patient may reveal a history of recent herpes infection or diabetes. A comprehensive history of prior and current conditions is often obtained.

Physical Exam

Examination of Bell’s palsy patient can reveal a nasolabial fold (flattened crease between the nose and the upper lip), a smooth forehead, palpebral fissure width (added distance between the top and bottom eyelids), drooling or facial asymmetry.  No symptoms in the central nervous system are often observed. The neck and ear will be observed fully for any conditions that may contribute to the symptoms.  A problem in the central nervous system can be suspected if the face is paralyzed save for the forehead. The severity of the symptoms and dysfunctions are graded from I to VI based on standard definitions.


There is no definite test to confirm Bell’s palsy; the doctor’s observation is the means for initial diagnosis of Bell’s palsy. To rule out underlying conditions such as infectious disease, neoplastic disease, diabetes, or other immunologic or autoimmune disease laboratory tests may be needed. These tests can include blood chemistries, antinuclear antibodies, C-reactive protein, ESR (erythrocyte sedimentation rate), and CBC (complete blood count).  To exclude Lyme disease, a Lyme titer may be performed.  If Wegener granulomatosis is suspected to cause Bell’s palsy, a cANCA (antineutrophil cytoplasmic antibody) test may be done.

To test for corneal sensation and hearing, a thorough cranial nerve examination is done, including a tuning fork examination. A taste test may also be done as well as an audiometry test to test for hearing. To test for nerve excitability, an EMG or electromyography may be performed to observe facial paralysis. This means measuring electroneuronography to assess the extent of nerve fiber degeneration as well as measuring for voluntary motor activity.

To observe for eyelid movements a blepharokymographic analysis may be performed. This can confirm diagnosis of Bell’s palsy which can lead to a prognosis.

CT scan, MRI, x-ray and other Imaging tests may be done to evaluate other possible factors like skull fracture, tumor or infection.

Christina Prieto, AP
1617 Hillcrest St
Orlando, FL 32803
Phone: 407-234-6454