Hemifacial Spasm:
When a Wink Is Not a Wink

Gary E Cordingley, MD, PhD
If thy right eye offends thee, don't pluck it out and cast it from thee.
Treatment is available.
I'm sure it's happened to you. Someone caught your eye by apparently winking at you. But when you looked
again, you realized that the person wasn't winking. Instead, he or she had recurrent muscular contractions
around one eye unrelated to any attempts to flirt or send a personal message. Moreover, the person might
have had twitching on one side of the mouth, as well. What you observed is called hemifacial spasm, an
involuntary movement disorder.

This condition typically afflicts people over forty years old and affects women more often than men. The
prevalence of this condition is unknown. While about ten people out of a population of 100,000 receive
treatment for this condition, other cases probably go uncounted because they don't enter the medical system
or get misdiagnosed.

For the person with the movement disorder this is an everyday, all-day phenomenon. It's usually annoying, and
sometimes more than just annoying. The repetitive muscular twitches and contractions affecting the upper and
lower eyelids can even interfere with vision. Fortunately, just one eye is impacted, so the other eye remains
open. But even if the person has normal vision in the unaffected eye, viewing the world with just one eye
reduces depth-perception. We need both eyes looking simultaneously in order to accurately judge how far
away objects are. If you want to prove this to yourself, walk around your house with one eye closed.

We read so much into the facial expressions of the people around us—and, in particular, what their eyes are
doing—that when an involuntary movement disorder generates its own facial distortions, it disrupts
communication and disconcerts not just the affected individual, but those around him or her, as well.

Hemifacial spasm can be confused with other conditions affecting the face. Like hemifacial spasm, Bell's palsy
affects the muscles on just one side of the face, but causes weakness rather than over-activity. Also like
hemifacial spasm, trigeminal neuralgia affects just one side of the face, but causes pain instead of twitching.
Finally, a condition known as blepharospasm (or Meige syndrome) involves involuntary contractions of eye and
face muscles, but affects both sides of the face simultaneously.

What causes hemifacial spasm? The various muscles affected by this disorder are connected to the so-called
facial nerve which is like a telephone cable containing many individual nerve-fibers. The nerve-fibers transmit
electrical impulses to the facial muscles. We have two facial nerves, one for each side of the face, and either
can be afflicted by this condition. In hemifacial spasm, one facial nerve transmits excessive and inappropriate
nerve-impulses to its associated muscles, causing unwanted movements. The nerves are capable of
conducting normal nerve-messages, too, so affected individuals can still use their facial muscles for more
appropriate movements.

The excessive impulses causing the movement disorder can be generated in the nerve-fibers themselves, or in
the brainstem (located at the base of the skull, connecting the brain above to the spinal cord below) which is
where the nerves originate. A dangerous underlying cause is not found in most people with hemifacial spasm,
but occasionally this disorder is found due to tumors, strokes or multiple sclerosis, so medical evaluation is
definitely warranted.

What can be done for this annoying condition? Until a decade or so ago, the main treatment was with certain
drugs also used in patients with epileptic seizures. Hemifacial spasm is not epilepsy, but it's not hard to imagine
why some of the same drugs might be useful. In epilepsy excessive electrical discharges are generated in brain
cells. Antiepileptic drugs simmer down or prevent these excessive discharges. Because the facial nerve-cells
share many electrical characteristics with brain cells, the same drugs can also reduce the extra nerve-impulses
causing hemifacial spasm. Some of the more frequently prescribed drugs include carbamazepine (brand name
Tegretol), gabapentin (Neurontin) and clonazepam (Klonopin).

Also, surgical treatments have been applied to some patients with hemifacial spasm. The operation seeks to lift
a small, abnormal blood vessel compressing the facial nerve where it emerges from the brainstem, but this
treatment carries significant risk and its beneficial effects do not always persist.

In the last decade or so, botulinum toxin has emerged as an extremely helpful treatment for hemifacial spasm
and is now the usual treatment of first choice. Botulinum toxin is available in two formulations—Botox (made by
the Allergan company) and Myobloc (made by Solstice Neurosciences). Thus far, the U.S. Food and Drug
Administration has approved just the Botox formulation for treatment of hemifacial spasm.  

Botulinum toxin is injected via a fine needle. In the case of the thin muscles around the eye, the drug is usually
deposited over the surfaces of the muscles. When used for muscles lower in the face, the drug is injected
inside the muscles. The drug acts at the microscopic connections between nerve-fibers and muscles by
blocking the activation of muscle-cells by incoming nerve-impulses.  So treatment with botulinum toxin interferes
with both the wanted as well as unwanted muscular contractions.

The drug is administered no more often than every three months. In many cases, less frequent treatments
suffice. A beneficial weakening effect is usually noticed within the first 7-10 days and the weakness is maximal
by 4-6 weeks. Gradual strengthening (and increased twitching) of treated muscles occurs thereafter. With
repeated injections the dosing format is optimized to achieve the best result for each individual.

Although hemifacial spasm is not a life-or-death condition, it can interfere with quality of life. While the available
treatments are not necessarily curative—or even convenient—they can reduce distress, improve function, and
keep those apparent winks from sending unintended messages.

(C) 2005 by Gary Cordingley