BOTULINUM TOXIN TYPE-A IN CEREBELLAR TREMOR CAUSED BY MULTIPLE-SCLEROSIS

The intention tremor seen in chronic progressive multiple sclerosis is often disabling and existing treatments are of limited benefit. The p resent pilot study was designed to assess the role of Botulinum toxin type A (BOTOX(R)) in such cases. Five patients with the condition rece ived 40 mouse units of toxin into the flexor and extensor compartments of the forearm. Two of these went on to receive a further 100 mouse u nits 2 months after the previous injection. Tremor was assessed at 0, 2 and 8 weeks post-injection using a validated clinical rating scale, spirography and handwriting samples, and a clinician's global rating s cale; functional capacity was measured using an activities of daily li ving (ADL) scale adapted for use in tremor. No statistically significa nt improvement occurred in intention tremor, although there was a tren d toward a mild improvement in the clinician's global rating scale. Pa tients noted an increase in their pre-existing corticospinal weakness which proved to be dose-limiting. No change occurred in ADL scores. It is concluded that pre-existing weakness limits the use of Botulinum t oxin in the intention tremor seen in multiple sclerosis, but further w ork in disabling primary and secondary cerebellar degenerations withou t corticospinal weakness may be worthwhile.