Optimising the methods of evaluation of the effectiveness of botulinum toxin treatment of post-stroke muscle spasticity
- Correspondence to: Professor A M O Bakheit Neurological Rehabilitation, Peninsula Medical School and Plymouth Primary Care Trust, Mount Gould Hospital, Plymouth PL4 7QD, UK; magid.bakheitpcs-tr.swest.nhs.uk
The correct research design is crucial in establishing whether treatments for complex neurological disorders are effective
The effectiveness of botulinum toxin type A (BtxA) in reducing post-stroke muscle hypertonia and its complications has been demonstrated in adult patients in at least eight large randomised controlled trials (RCTs).1–8 The clinical benefits were reported when diverse treatment protocols and different dose schedules and injection techniques were used for the management of the same clinical indication. Nonetheless, some doubt as to the value of this treatment remain.9 What is the explanation for this apparent paradox? The contradiction may be explained by the inadequate design of these studies and the inherent difficulties with the interpretation of the results of RCTs of a drug treatment that is carried out in the context of rehabilitation for a person with chronic neurological disability. The WHO classification of functioning, disability, and health10 provides a useful framework for understanding the complex relation between the statistical significance and the clinical significance of a given treatment and helps to explain the complexity of rehabilitation research. A statistically significant change at the level of impairment (as a result of the intervention) may not alter the subject’s functional abilities or potential for social participation. The outcome of treatment with BtxA is clinically significant only if it results in the full or partial attainment of functional goals that are meaningful to the recipient of this treatment. An example of such outcomes is the achievement of safe walking and prevention of falls in a patient with dynamic foot equinus after BtxA injections into the calf muscles. Successful treatment reduces muscle …
