Anticholinergics are one of the most common treatments used in adult-onset
focal dystonias although their general efficacy has not been proven. We have investigated the effects of
intravenous administration of
atropine,
benztropine and
chlorpheniramine, in comparison to
normal saline, in 20 patients with adult-onset
focal dystonias (
spasmodic torticollis (9), cranial
dystonia (6),
writer's cramp (5), and have retrospectively reviewed the notes of 78 patients (
spasmodic torticollis (38), cranial
dystonia (25),
writer's cramp (15), who had received chronic oral
anticholinergic therapy in varying doses at some time in the past. Patients with
spasmodic torticollis and
writer's cramp showed no consistent change with any of the intravenous drugs, while the few with cranial
dystonia who improved usually did so at the expense of
drug-induced sedation. The natural variability of these disorders was evident in the response to
normal saline, which caused changes in the scores for severity of the
involuntary movements of 20% or more in some patients. Only 8 of the patients who had received chronic oral
therapy obtained more than mild benefit, and in 3 of them this improvement was transient. We conclude that
cholinergic mechanism are not of general or prime importance in the pathogenesis of adult-onset
focal dystonias. However, each new patient warrants a trial of chronic oral
anticholinergic therapy in view of the occasional useful responses obtained with these drugs.