Clinical correlates of response to botulinum toxin injections
J. Jankovic and K. S. Schwartz
Department of Neurology, Baylor College of Medicine, Houston, Tex. 77030.
We studied 242 patients with cervical dystonia who had adequate follow-up
after botulinum toxin injections to determine which clinical variables had
a predictive value in the treatment outcome. Twenty-one patients (16%)
categorized as nonresponders were compared with 113 patients (47%)
considered to be definite responders. On average, the nonresponders had
symptoms for 14 years longer than responders. Seventy-eight of 100 patients
with complications were female compared with 54% of 190 patients without
complications. In addition, patients with complications weighed less than
those without complications. Both findings suggest that the occurrence of
complications is related to smaller mean neck muscle mass. Botulinum toxin
antibodies were detected in 35.7% of the nonresponders tested and in none
of the responders. This comprehensive analysis of outcome variables leads
us to conclude that patients with a long duration of dystonia before their
first botulinum toxin injection respond less well than those with a short
duration of symptoms, that some patients lose their responsiveness because
of the development of blocking antibodies, and that women are more likely
to develop complications, such as dysphagia and neck weakness, than are
men.
