ASSESSMENT: BOTULINUM NEUROTOXIN FOR THE TREATMENT OF SPASTICITY (AN EVIDENCE-BASED REVIEW)

To the Editor:

The Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology (AAN) recommends that botulinum neurotoxin (BoNT) should be offered as an option for the treatment of spasticity.¹ Despite offering a Level A rating of evidence in support, the authors noted that functional voluntary use of the affected arm after stroke and leg in cerebral palsy did not improve across their citations of trials.

Quality of life was not improved by, for example, lessening joint pain. No cost-benefit analysis was offered for utility. The trials only revealed that passive range of motion or resistance to ranging a joint temporarily improved after focal injections compared to no intervention in control subjects. This finding comes from the Ashworth scale, which has high interrater reliability because it separates very stiff from not as stiff resistance at one joint at rest in the trials. The change may lead to an increase in mobility of a joint angle for hygiene or for pulling a shirtsleeve over a hemiplegic arm. Is that passive result any more than a cosmetic effect for patients with stroke affecting the arm who pay for an anti-wrinkle drug?

The Subcommittee calls for more research to develop a tool that can measure the potential benefits of this class of drugs. The authors should clarify if the Level A evidence is based on a poor outcome measure. In addition, there is consensus that the Ashworth score is not a clinically, biologically, or electrophysiologically sound surrogate for whatever aspect of the upper motor neuron syndrome it has been overutilized to reflect.²

The Subcommittee also calls for studies to assess optimal dosing and localization in muscle fibers of the paralytic injectable. This will not matter unless an important clinical outcome can be defined. The group also calls for better assessment of overactivity …