The term “facial tic” is often used to describe involuntary movements that involve the face, particularly those around the eyes and the corner of the mouth. These movements are usually brief and not sustained. They are usually not associated with the “squeezing” of the muscles around the eyes that typically accompanies blepharospasm.
The common facial tic includes the condition hemifacial spasm, a condition characterized by very rapid, abnormal contractions of one side of the face. Sometimes hemifacial spasm may follow Bell's palsy (Bell's palsy is a form of temporary facial paralysis resulting from damage or trauma to one of the two facial nerves.) or be associated with facial weakness. Often the movements are provoked by eating, talking, or whistling. Some patients experience symptoms in the upper areas of the face when they move the lower part of the face.
Another facial tic is the quick facial movements that occur in people who have chronic motor tics. Chronic motor tics may affect one or both sides of the face, and the movement is usually preceded by an urge to make the movements. After the movement is made, the urge is often relieved. The individual with chronic motor tics usually has the ability to suppress the movements if they concentrate on the movements. Chronic motor tics may involve any part of the body including the face, arms, legs, or trunk.
The manifestation of blepharospasm is an involuntary movement that involves the upper face, and may also involve the lower face, tongue, pharynx, jaw, neck, or other body segments. However, these movements are usually not suppressible, because they are involuntary and not under the direct control of the person with them.
There is some overlap among how blepharospasm and tics appear, so that even experts may disagree on whether a patient has chronic motor tics or blepharospasm. Most of the disagreement will occur when the symptoms are subtle, and they present with similar findings on examination. Taking a history will sometimes clarify the cause. Hemifacial spasm and blepharospasm are known to have an excellent response to botulinum toxin treatment. Facial tics may respond, too.
What is the difference between essential tremor and dystonia tremor?
Essential tremor is one of the most common movement disorders. It is usually inherited. The tremor is not present when someone is relaxed but becomes evident when a body part assumes a posture or undertakes a specific action. The tremor is generally rhythmic and can vary from being only subtle to very severe and debilitating. The tremor affects the hands and arms and may affect the head and the voice.
Dystonic tremors are quite variable in their presentation and on some occasions can look like essential tremor. They are, however, seldom seen in isolation and usually are associated with dystonic body postures. The tremors are also sometimes somewhat more irregular than what is seen with essential tremor. Because essential tremor and dystonia tremor may look the same and both can be genetic, researchers have investigated whether patients with essential tremor might carry an abnormality in the DYT1 gene that is associated with early onset genetic dystonia. This has been found not to be the case although the actual gene for essential tremor has not been identified.