Dystonia, botulinum neurotoxin, and the aviator

Dystonia is both a symptom and the name for group of illnesses called the dystonias. The physical manifestation consists of sustained, involuntary contractions of the muscles in one or more parts of the body, resulting in twisting or distortion of that part of the body. For focal dystonias including torticollis, blepharospasm and spasmodic dysphonia, botulinum toxin injections have become the treatment of choice because of the ability of this toxin to sufficiently weaken the muscle to reduce the spasm but not so much as to cause paralysis. This paper involves the fate of four airmen all afflicted with a form of dystonia who had been reviewed in the Aeromedical Certification Division of the FAA Civil Aeromedical Institute.