Original Editor - Wendy Walker.
Topic Expert - Wendy Walker
- 1 Introduction
- 2 Clinically Relevant Anatomy
- 3 Causes of Peripheral Facial Palsy
- 4 Risk factors
- 5 Clinical Presentation
- 6 Differential Diagnosis
- 7 Diagnostic Procedures
- 8 Outcome measures
- 9 Management / Interventions
- 10 Complications/Sequelae
- 11 Effects on Quality of Life
- 12 Resources
- 13 References
Facial palsy is due to the damage in the facial nerve that supplies the muscles of the face. It can be categorized into two based on the location of casual pathology:
- Central facial palsy- due to damage above the facial nucleus
- Peripheral facial palsy-due to damage at or below the facial nucleus
Clinically Relevant Anatomy
For more detail on the anatomy of the facial nerve, please see the Facial Nerve page.
The VIIth cranial Nerve has its nucleus in the Pons and takes a rather winding route before exiting the skull through the stylomastoid foramen. It then passes through the parotid gland, splitting into 5 branches: Temporal, zygomatic, buccal, mandibular and cervical.
See Facial Muscles Video :facial Muscles
Causes of Peripheral Facial Palsy
There are several causes of Facial Palsy:
- Idiopathic or Bell's palsy - Cause not known  but likely to be linked to Herpes Simplex infection 
- Tumour - A tumour compressing the facial nerve can result in facial paralysis, but more commonly the facial nerve is damaged during surgical removal of a tumour. The most common tumour to result in facial palsy during surgical removal is the Acoustic Neuroma (AKA Vestibular Schwannoma). Less commonly, cholesteatoma, hemangioma, Facial Schwannoma or parotid gland tumours (or the surgery to remove them) are the cause.
- Ramsay Hunt Syndrome - Caused by Herpes Zoster infection = a syndromic occurrence of facial paralysis, herpetiform vesicular eruptions, and vestibulocochlear dysfunction. Patients presenting with Ramsay Hunt syndrome generally have a greater risk of hearing loss than do patients with Bell palsy, and the course of disease is more painful. Moreover, a lower recovery rate is observed in these patients.
- Lyme Disease - Infection with Borrelia burgdorferi via tick bites is another cause of facial paralysis. Of patients affected with Lyme disease, 10% develop facial paralysis, with 25% of these patients presenting with bilateral facial palsy.
- Iatrogenic Facial Nerve Damage - Iatrogenic facial nerve injury occurs most commonly in temporomandibular joint replacement, mastoidectomy, and parotidectomy.
- Rare causes - These include:
- Neurosarcoidosis, Otitis media, Multiple Sclerosis, Moebius Syndrome, Melkersson-Rosenthal syndrome, Guillain-Barre Syndrome, Millard-Gubler Syndrome AKA Ventral Pontine Syndrome (Ipsilateral facial palsy with contralateral hemiplegia caused by involvement of the corticospinal tract along with paralysis of lateral rectus on the ipsilateral side due to the involvement of the abducent nerve), Foville Syndrome AKA Inferior Medial Pontine Syndrome (ipsilateral facial palsy, contralateral hemiplegia with ipsilateral conjugate gaze effects), Eight-and-a-half syndrome (facial palsy with Internuclear ophthalmoplegia and horizontal gaze palsy)
- Trauma, especially temporal bone fractures
- Pregnancy - might be due to hypercoagulability, elevated blood pressure, increased fluid load, virus infection and suppressed immunity
- Exposure to cold
- Infection of ear
- Upper respiratory tract infection
- Obesity 
Paralysis of the muscles supplied by the Facial Nerve presents on the affected side of the face as follows:
Appearance and Range of Movement:
- Inability to close the eye
- Inability to move the lips eg. into a smile, pucker
- At rest, the affected side of the face may "droop"
- The lower eyelid may drop and turn outward - "ectropion"
- Difficulty eating and drinking as lack of lip seal makes it difficult to keep fluids and food in the oral cavity
- Reduced clarity of speech as the "labial consonents" (ie. b, p, m, v, f) all require lip seal
- Dryness of the affected eye - see the Dry Eye page for more details
The facial nerve supplies the lachrymal glands of the eye, the saliva glands, and to the muscle of the stirrup bone in the middle ear (the stapes). It also transmits taste from the anterior 2/3 of the tongue.
Facial palsy often involves:
- Lack of tear production in the affected eye, causing a dry eye, with risk of corneal ulceration.
- In Facial Nerve palsy there are 2 problems which contribute towards making the eye dry:
- The greater petrosal nerve, derived from the facial nerve, supplies the parasympathetic autonomic component of the lacrimal gland. - controlling the production of moisture/tearing in eyes.
- The zygomatic branch of the Facial Nerve supplies Orbicularis Oculi, and the resulting paralysis causes inability(or reduced ability) to close the eye or blink, so the tears (or indeed artificial lubrication in the form of drops, gel or ointment) are not spread across the cornea properly.
- Hyperacusis = sensitivity to sudden loud noises
- Altered taste sensation.
Upper Motor Neuron versus Lower Motor Neuron
If the forehead is not affected (ie the patient is able to raise fully the eyebrow on the affected side) then the facial palsy is likely to be a result of a lesion in the Upper Motor Neuron (UMN). Paralysis which includes the forehead, such that the patient is unable to raise the affected eyebrow, is a Lower Motor Neuron (LMN)lesion.
However, caution is advised in using preservation of forehead function to diagnose a central lesion. Patients may have to spare of forehead function with lesions in the pontine facial nerve nucleus, with selective lesions in the temporal bone, or with an injury to the nerve in its distribution in the face. It is worth remembering that a cortical lesion that produces a lower facial palsy/paresis is usually associated with a motor deficit of the tongue and weakness of the thumb, fingers, or hand on the ipsilateral side.
- Laboratory investigations include an audiogram, nerve conduction studies (ENoG), computed tomography (CT) or magnetic resonance imaging (MRI), electromyography (EMG).
- According to a clinical guideline, clinicians should not obtain routine laboratory and imaging testing in patients with new-onset Bell’s palsy.
- Sunnybrook Facial Grading System
- House-Brackmann facial nerve grading scale
- Linear Measurement Index
- Facial Disability Index
- Lip-length (LL) and Snout (S) Indices
- Five-Point Scale
Management / Interventions
Medical and surgical management depends on the cause of facial palsy.
Acoustic Neuromas or Facial Schwannomas are frequently resected surgically. See Acoustic Neuroma page for more details.
Patients at high risk of a corneal ulcer may be offered oculoplastic surgery to protect the eye.
For patients with dense facial palsy and no nerve function, a number of surgical interventions may be used. These fall into the following categories:
- Facial reanimation surgeries which involve nerve graft or anastomosis
- Facial reanimation surgeries which involve muscle transposition
- Static surgeries, ie. plastic surgery to improve symmetry at rest but no improvement in movement
- Neuromuscular Retraining (NMR) 
- Electromyography (EMG) and mirror biofeedback 
- Trophic Electrical Stimulation (TES) 
- Proprioceptive Neuro Muscular Facilitation Techniques
- Kabath technique
- Mime's therapy
Evidence of Physiotherapy Treatments
- According to clinical practice guidelines, physiotherapy is not recommended in Bell's palsy.
- Mime therapy can improve functionality for patients with facial palsy. The therapy must consist of exercises with mirrors, which are both low cost and easily available, and the patient must help in the execution of the movements for both biofeedback purposes and to prevent synkinesis.
- Effect of electric stimulation is controversial.
- PNF technique is effective than conventional exercises.
- Kabath technique is effective than no exercise.
Synkinesis (AKA aberrant regeneration) occurs after injury to the facial nerve. For more information on this, see the dedicated Synkinesis page.
Effects on Quality of Life
A large retrospective study [920 patients] published in September 2018 looked into the correlation between facial palsy severity and quality of life; it concluded "A correlation between facial palsy severity and quality of life was found in a large cohort of patients comprising various etiologies. Additionally, novel factors that predict the quality of life in facial palsy were revealed".
Here's a link to the Facebook group for Facialpalsy.org
This link is to an introductory video about the effects of facial palsy
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