Factors predicting the efficacy of botulinum toxin-A treatment of the lower limb in children with cerebral palsy

Botulinum toxin A is widely used for spasticity management in children with cerebral palsy, although outcomes are unpredictable. The aim of this study was to identify criteria for selecting patients most likely to benefit from botulinum toxin A treatment. Fifty-five subjects, aged 2.5 to 18 years, were recruited. The assessment covered measures of spasticity (Modified Ashworth Scale), function (using the Gross Motor Function Measure and the Physician's Rating Scale), selective motor control, static range of motion at the ankle with knee extended and flexed, range of motion of the knee flexors, central and peripheral vision, and cognitive ability. Outcomes at 3 months were compared with baseline values. All of the scales showed significant differences between pre- and postinjection values. Significantly increased Gross Motor Function Measure scores were found in children aged 48 months or under and in those able to walk with support. Greater improvements in selective motor control and Physician's Rating Scale were seen in those with a less severe pattern of paralysis, lower levels of impairment, the ability to walk (with or without support), normal visual acuity, and normal or borderline cognition. We identified factors that mark out patients as most likely to achieve functional gains: young age, hemiplegia or diplegia, slight to moderate disability, walking with support, normal or borderline cognition, and normal or borderline visual acuity.