The first drug treatment for severe stuttering may bring substantial relief to individuals who now have extreme difficulty communicating, researchers said Thursday.
The new treatment directly attacks the mechanisms of stuttering: strong, inappropriate movements of the lips, tongue and vocal cords, to the point that the vocal cords sometimes lock together.
Neurologist Mitchell F. Brin of Columbia University in New York City reported at a meeting of the American Academy of Neurology here that he treated seven such patients by injecting their vocal cords with tiny amounts of botulinum toxin, the powerful poison that in larger doses causes botulism and death.
The toxin relaxed the muscles, allowing four of the seven to speak much more easily and clearly, without any significant side effects, he reported.
Brin is enthusiastic about the technique because he has already used it to successfully treat more than 500 patients with a related disorder, spasmodic dysphonia, in which the vocal chords undergo speech-preventing spasms. He thinks it could have wide application if it is proved effective in further tests.
About 2.5 million Americans stutter. Some scientists still believe that stuttering is primarily a psychological problem, but a growing body of evidence indicates that many forms of the disorder may be caused by subtle neurological abnormalities that impair control of the muscles involved in speech.
Brin's finding provides further evidence that stuttering has a biological origin, said speech-language pathologist Charles Diggs of the American Speech-Language-Hearing Assn. in Rockville, Md.
The new results with stutterers are "very encouraging," Diggs said, "but it obviously needs more research."
Brin said that "we took the worse cases (of stuttering) we could find for the initial studies. They were very, very disabled. Four out of the seven are still coming back for therapy and are very happy with it. The other three didn't think they got adequate benefit."
Brin noted that one patient has been on the therapy for a year with no diminishment in effectiveness, and others are approaching that length of treatment.
Botulinum toxin, commonly known as botox, is used for treatment of a variety of muscle disorders. One is blepharospasm, in which the eyelids spasm closed, rendering the victim functionally blind even though vision is not impaired. Another is torticollis, or "wry neck," is which muscle spasms cause the head to be persistently tilted to one side. Strabismus, or crossed eyes, is a third.
Administration of botox into the affected muscles relieves all three problems. In the case of strabismus, the cure is permanent. In the other cases, as well as in treatment of stuttering, the effects last for three to four months, at which time the treatment must be repeated.
The injections are "uncomfortable but not painful," Brin said, and do not require anesthesia. Patients usually become much more comfortable with the procedure after the first injection, he said.
The only significant side effects, he said, are that some patients talk in a whisper and others have trouble swallowing liquids. Both problems clear up within a week.