A randomized, double masked, controlled trial of botulinum toxin type A in essential hand tremor.
OBJECTIVE
To evaluate the safety and efficacy of botulinum toxin type A injection in essential tremor of the hand.


BACKGROUND
Botulinum toxin type A is an effective treatment for dystonia, spasticity, and other movement disorders and has been found to be useful in open-label studies and one double-masked study of essential hand tremor.


METHODS
One hundred thirty-three patients with essential tremor were randomized to low-dose (50 U) or high-dose (100 U) botulinum toxin type A (Botox) or vehicle placebo treatment. Injections were made into the wrist flexors and extensors. Patients were followed for 16 weeks. The effect of treatment was assessed by clinical rating scales, measures of motor tasks and functional disability, and global assessment of treatment. Hand strength was evaluated by clinical rating and by a dynamometer.


RESULTS
Both doses of botulinum toxin type A significantly reduced postural tremor on the clinical rating scales after 4 to 16 weeks. However, kinetic tremor was significantly reduced only at the 6-week examination. Measures of motor tasks and functional disability were not consistently improved with botulinum toxin type A treatment. Grip strength was reduced for the low- and high-dose botulinum toxin type A groups as compared with the placebo group. Adverse reactions consisted mainly of dose-dependent hand weakness.


CONCLUSIONS
Botulinum toxin type A injections for essential tremor of the hands resulted in significant improvement of postural, but not kinetic, hand tremors and resulted in limited functional efficacy. Hand weakness is a dose-dependent significant side effect of treatment at the doses used in this study.
Brin
M F
MF
Department of Neurology, Columbia University, New York, NY, USA.
Lyons
K E
KE
Doucette
J
J
Adler
C H
CH
Caviness
J N
JN
Comella
C L
CL
Dubinsky
R M
RM
Friedman
J H
JH
Manyam
B V
BV
Matsumoto
J Y
JY
Pullman
S L
SL
Rajput
A H
AH
Sethi
K D
KD
Tanner
C
C
Koller
W C
WC
D000368:Aged; D019274:Botulinum Toxins, Type A / Q000008:administration & dosage*; D004311:Double-Blind Method; D020329:Essential Tremor / Q000188:drug therapy*; D005260:Female; D006225:Hand; D018737:Hand Strength; D006801:Humans; D008297:Male; D008875:Middle Aged; D009465:Neuromuscular Agents / Q000008:administration & dosage*; D016896:Treatment Outcome
D009465:Neuromuscular Agents; D019274:Botulinum Toxins, Type A