There are several limitations to this study, therefore these results should be regarded as preliminary. Further research consistent with the above indications is needed to investigate the impact of this new treatment option in patients with cerebral palsy.
This study evaluated the efficacy and safety of three doses of botulinum toxin A (BTX-A; Dysport) in 125 patients (mean age 5.2 years, SD 2; 54% male)with dynamic equinus spasticity during walking. Participants were randomized to receive Dysport (10, 20, or 30 units/kg) or placebo to the gastrocnemius muscle of both legs. Muscle length was calculated from electrogoniometric measurements and the change in the dynamic component of gastrocnemius shortening at four weeks was prospectively identified as the primary outcome measure. All treatment groups showed statistically significant decreases in dynamic component compared with placebo at 4 weeks. Mean improvement in dynamic component was most pronounced in the 20 units/kg group, being equivalent to an increase in dorsiflexion with the knee extended at 19 degrees, and was still present at 16 weeks. The safety profile of the toxin appears satisfactory.
BACKGROUND: Although botulinum toxin is a well-established treatment of focal spasticity in cerebral palsy, most trials have been small, and few have simultaneously assessed measures of muscle tone and clinical benefit.
Background and purpose
To support clinical decision‐making in central neurological disorders, a physical examination is used to assess responses to passive muscle stretch. However, what exactly is being assessed is expressed and interpreted in different ways. A clear diagnostic framework is lacking. Therefore, the aim was to arrive at unambiguous terminology about the concepts and measurement around pathophysiological neuromuscular response to passive muscle stretch.
Methods
During two consensus meetings, 37 experts from 12 European countries filled online questionnaires based on a Delphi approach, followed by plenary discussion after rounds. Consensus was reached for agreement ≥75%.
Results
The term hyper‐resistance should be used to describe the phenomenon of impaired neuromuscular response during passive stretch, instead of for example ‘spasticity’ or ‘hypertonia’. From there, it is essential to distinguish non‐neural (tissue‐related) from neural (central nervous system related) contributions to hyper‐resistance. Tissue contributions are elasticity, viscosity and muscle shortening. Neural contributions are velocity dependent stretch hyperreflexia and non‐velocity dependent involuntary background activation. The term ‘spasticity’ should only be used next to stretch hyperreflexia, and ‘stiffness’ next to passive tissue contributions. When joint angle, moment and electromyography are recorded, components of hyper‐resistance within the framework can be quantitatively assessed.
Conclusions
A conceptual framework of pathophysiological responses to passive muscle stretch is defined. This framework can be used in clinical assessment of hyper‐resistance and will improve communication between clinicians. Components within the framework are defined by objective parameters from instrumented assessment. These parameters need experimental validation in order to develop treatment algorithms based on the aetiology of the clinical phenomena.
To assess the efficacy and safety of repeat abobotulinumtoxinA injections in reducing upper limb spasticity in children with cerebral palsy (CP). METHOD This was a double-blind, repeat-cycle study (NCT02106351) in children with CP (2-17y). Children were randomized to receive 2U/kg (control), 8U/kg, or 16U/kg abobotulinumtoxinA injections into the target muscle group (wrist or elbow flexors) and additional muscles alongside occupational therapy via a home-exercise therapy program (HETP; minimum five 15min sessions/wk). Children received 8U/kg or 16U/kg plus HETP in cycles 2 to 4. RESULTS During cycle 1, 210 children (126 males, 84 females; mean age [SD] 9y [4y 5mo], range 2-17y; n=70/group) had at least one upper limb abobotulinumtoxinA injection and 209 complied with the HETP. At week 6 of cycle 1, children in the 8U/kg or 16U/kg groups had significantly lower Modified Ashworth scale scores versus the 2U/kg group (primary outcome: treatment differences of-0.4 [p=0.012] and-0.7 [p<0.001] respectively). All groups improved on Physician Global Assessment and children in all groups achieved their treatment goals at least as expected. Therapeutic benefits were sustained during cycles 2 to 4; muscular weakness was the only treatment-related adverse event reported in at least one child/group (4.3% and 5.7% vs 1.4% respectively). INTERPRETATION Treatment with 8U/kg or 16U/kg abobotulinumtoxinA significantly reduced upper limb spasticity versus the 2U/kg control dose. Therapeutic benefits of abobotulinumtoxinA plus HETP were sustained with repeat treatment cycles.
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