Disorders of facial motor function.

This review deals with a variety of disorders of facial movement. Recent publications on blepharospasm, facial spasm, facial myokymia, apraxia of lid opening and facial paralysis are referenced and discussed. In blepharospasm, carefully performed electromyographic studies reveal a variety of abnormal patterns of contraction of the oribicularis oculi and the levator palpebrae muscles confirming the clinical impression that blepharospasm is not a homogeneous disease. Similar studies are furthering the understanding of apraxia of lid opening, which may involve sustained contraction of the orbicularis oculi with or without failure of levator palpebrae inhibition. In both conditions botulinum toxin A injected pretarsally appears to be the preferred treatment. Of interest with respect to apraxia of lid opening is that it may be the result of a failure to sustain eye opening as well as an inability to open the eyes voluntarily. Although the fact that bilateral facial spasm was found in only five of 702 patients with spasm suggests that it is infrequent, it is also possible that bilateral facial spasm may be underdiagnosed because of lack of awareness of its existence. Despite the continued enthusiasm of neurosurgeons for microvascular decompression, the preferred treatment for facial spasm continues to be botulinum toxin A injections. It appears that a lesion of the dorsolateral pontine postgenu portion of the facial nerve is responsible for the facial myokymia of patients with multiple sclerosis. Interest in the study of lid function has increased as a result of the advent of the search coil technique for recording lid movements. Recordings with this technique have proven useful in facial nerve palsy for monitoring the degree and course of recovery and as a means of judging the effectiveness of therapy.