Facial Nerve Disorders-from Tics to Bells Palsy to Hemifacial Spasm

Nitin K Sethi, MD, MBBS, FAAN

sethinitinmd@hotmail.com

In this blog post, I shall discuss a number of disorders that affect the facial nerve.

The movements of the face are controlled by the facial nerve. This is the nerve which makes us smile, laugh, frown controlling numerous other facial expressions which humans possess. Facial nerve is a cranial nerve (cranial nerves, a set of 12 nerves originate in the brain). Facial nerve is cranial nerve VII (seven). The right facial nerve controls the muscles of facial expression on the right side of the face while the left facial nerve does the same for the left side of the face).

Innervation of the muscles of the face by facial nerve (cranial nerve VII) Henry Vandyke Carter and one more author – Henry Gray (1918) Anatomy of the Human Body. Image source: Facial Nerve Wikipedia. The image is on public domain and is reproduced here for educational purposes only.

There are a number of disorders which can affect the facial nerve. Some of these disorders cause twitching of the face (tics, hemifacial spasm) while others cause weakness/drooping of one side of the face (stroke, Bells palsy).

FACIAL TICS

Facial tics are repeated spasms which involve different muscles of the face (such as rapid eye blinking, nose twitching, head jerking, shoulder shrugs). Tics can be classified into simple motor tics (such as those listed above) and complex motor tics (in a complex motor tic, a series of movements are performed in the same order repeatedly). While tics occur involuntary, most patients are able to stop their tics (for a short period of time) if asked to do so. “Holding the tic in” though causes distress which is relieved by performing the tic. Tics are usually considered to be harmless but they may occur multiple times during the day causing distress and become socially disabling to the patient and those around). As a result, not all tics need to be treated. If the tics are not bothering the patient per se, I usually educate the patient/family on facial tics and what can exacerbate them (stress/anxiety, lack of sleep) and keep the patient under my observation. Many children/ youth may exhibit a transient tic disorder and then grow out of it. Tourette’s Syndrome is a chronic tic disorder characterized by multiple motor and vocal tics. If tics need treatment, behavioral therapy and medications are prescribed.

HEMIFACIAL SPASMS

As the name suggests, in hemifacial spasm the patient exhibits facial muscle contractions (spasms) involving one side of the face. The disorder is characterized as a movement disorder of the facial nerve in which muscles of one side of face twitch involuntary. Hemifacial spasm occurs when something irritates the facial nerve and the cause needs investigation. The diagnosis of HS is made by a neurologist based on observing the facial movements and results of test such as MRI brain (to look and see if anything is irritating the facial nerve/its branches inside the brain).

The treatment of HS depends on the cause. Various treatment options include use of medications (anticonvulsant drugs are sometimes prescribed), botulinum toxin (BOTOX) and surgery.

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