There are a range of tests that are carried out to, firstly, identify the cause of your facial palsy, and secondly, demonstrate how well the facial nerve functions.
With some forms of facial paralysis (such as Bell’s palsy), your treatment may be initially managed by your GP. Where the cause of the paralysis is unclear, then further tests may be carried out depending on your individual circumstances.
Magnetic resonance imaging (MRI)
An MRI of your brain including the length of your facial and auditory (hearing) nerve may be done. The MRI may also include images of the parotid (salivary) gland in your cheek, depending on your individual symptoms. It is done to identify what is causing your facial palsy, if a diagnosis cannot be made from the history of your symptoms alone.
Facial paralysis can be associated with hearing problems, and children in particular should be monitored. Loss of hearing in one ear can often be the first indication that something is wrong.
Eye and vision tests
Many people with facial palsy have difficulty closing their eyes or blinking. An ophthalmologist can check your eyes to make sure the eye itself is healthy. He will also check your eye movements to see if your eyes can move in all directions. A sight/vision test will identify any deterioration or damage to your sight. The ophthalmologist will give advice on how to protect your eye if it is not closing or blinking. The aim is to prevent you from developing dry patches and ulceration over the eyeball. He may also prescribe eye lubrication to keep your eye clean, moist and healthy.
Electrical nerve tests (neurophysiology)
At some point in the assessment or treatment of your facial palsy, you may undergo some electrical facial nerve testing. This will depend on the services available to you and your individual symptoms and diagnosis. Electrical testing is certainly not necessary in all cases, and much will depend on the service provision in your area. The tests identify how good the facial nerve is at carrying an electrical impulse along its path to the muscle fibres and how efficient it is at enabling the fibres to contract.
Needle electromyography (EMG)
A needle EMG is a technique used to assess and evaluate the amount of electrical activity being produced in the muscle. The electrical signals are recorded on a graph and analysed to detect any abnormalities.
A needle electrode is inserted into the muscle through the skin. This procedure is always done by a trained doctor who specialises in the field of electromyography. The activity of the muscle at rest is recorded. The patient is then asked to make a movement, and the electrical activity during movement is measured. The movement will depend on the muscle being assessed; for example it could be the smile muscle, so the patient will be asked to smile.
Needle EMG is only offered to a minority of people when there is uncertainty about the health of the facial nerve.
See our patient experience of a Needle EMG.
Surface electrical myography (sEMG)
This test is usually done by therapists involved in rehabilitation, such as a speech and language therapist, or a physiotherapist. Electrodes are placed over specific areas of the face, for example, the brow, temples, cheek, chin and neck. The person is then instructed to make a range of facial expressions. The electrodes will pick up the electrical activity in the muscle to see how well the nerve activates the muscle fibres. It will also show how well the nerve rests when the face is still.
Surface electrical myography is not as specific as a needle EMG, but it can show important information about how well the nerve is recovering. The results from the injured side of your face are compared to the normal (or uninjured) side of the face. Retesting after six-twelve months can give the therapist and the patient an idea about how well the nerve is recovering. However, sEMG it is not as exact as needle EMG and can only give a general indication about the degree of nerve damage/recovery, but it remains a useful test.
Last reviewed: 31-07-2019 || Next review due: 31-07-2022