Focal facial spasm.

An unusual case of focal facial spasm modified by factors affecting the peripheral facial nerve was investigated in a 32-year-old woman with involuntary contractions at the left mouth and nasal area. Voluntary facial movements were normal. The involuntary spasms ceased with digital pressure over the facial nerve in the left stylomastoid area. A difference between voluntary and these involuntary facial movements occurred both with local anesthetic blockade and with crushing of the facial nerve. Blink reflexes demonstrated unilateral left synkinesis, and facial EMG showed clonic discharges and individual motor units that discharged rapidly (200 Hz). Treatment with diphenylhydantoin, carbamazepine, and prednisone was ineffective. Neurolysis of the peripheral facial nerve resulted in temporary relief, whereas biofeedback controlled the spasms. Focal facial spasms may represent a disorder of the facial nucleus influenced by both peripheral and central mechanisms