Craniofacial Muscles

16 Spastic Facial Muscle Disorders
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seconds. It is unilateral, usually involving a single orbicularis oculi fi ber or small
fascicle of fi bers in lower eyelid. It does not close the eyelid fi ssure, even though it
is occasionally forceful enough to cause oscillopsia. Men and women are equally
affected. Its onset is acute and usually correlates with stress, fatigue, caffeine, or
alcohol consumption. Treatment is usually not necessary, since it is self-limiting
and usually lasts for less than a week. The longest reported case of eyelid myokymia
is 13 years.
16.3 Hemifacial Spasm
Hemifacial spasm affects the entire side of the face and neck unilaterally, and is
related to facial nerve irritation mainly at its exit from the brainstem. Hemifacial
spasm differs from blepharospasm and other features of cranial dystonia in that the
spasms remain unilateral in hemifacial spasm, whereas in blepharospasm there is
nearly always bilateral involvement. Rarely, hemifacial spasm is bilateral; in such
cases the movements on the two sides of the face are asynchronous, in contrast to
the simultaneous bilateral movements of cranial dystonia. In hemifacial spasm,
spontaneous contraction is often more of a spasm than a twitch. It may persist during
sleep unlike blepharospasm and, in general, cannot be altered by sensory tricks.
However, emotion and stress frequently aggravate the condition (Castelbuono and
Miller 1998 ; Defazio and Livrea 2002 ) .
16.4 Aberrant Regeneration of Facial Nerve (Facial
Synkinesia or Facial Nerve Misdirection
A history of facial paralysis or facial nerve injury as well as electrophysiologic studies,
might be helpful in revealing signs of synkinesis. As a simple test for aberrant
regeneration, patients can be asked to pucker their lips to see if the eyelid fi ssure
becomes narrow because of increased orbicularis muscle tone (Nerad et al. 2008 ) .
Like hemifacial spasm, these spasms persist during sleep.
16.5 Neurologic Disorders
Neurodegenerative disorders , especially those affecting the basal ganglia, such as
Parkinson’s disease, progressive supranuclear palsy, Huntington’s disease and
Wilson’s disease, can produce various combinations of spontaneous blepharospasm,
re fl ex blepharospasm, and apraxia of eyelid opening, in addition to involuntary
movements of the lower face. Patients with these lesions typically have additional
neurologic signs.