Lower limb muscle activity in ambulatory children with cerebral palsy before and after the treatment with Botulinum toxin A

Purpose: The study investigated the effect of Botulinum toxin A on the gait and lower limb muscle activity of ambulatory CP children. Methods: 19 spastic diplegic and 4 left hemiparetic CP children were inject ed with a mean dose of 23.5 units of Botulinum toxin A/kg body weight into the gastrocnemius and hamstring muscles. Muscle tone and gait analysis incl uding the kinesiological electromyogram of the shank and thigh muscles were assessed before and four weeks after injection and compared with the help of a multivariate analysis (p < 0.05). Results: Botulinum toxin A caused a definite reduction of plantarflexor, kn ee and hip hypertonia in 21 children, resulting in a more plantar grade and erect gait in 17 children four weeks after injection. Gait analysis showed a statistically significant improvement ia peak ankle dorsiflexion and kne e extension during stance, and the length of the force point of action unde r both feet increased. Electromyography revealed significantly less co-cont raction of the lower leg muscles, due to a more phasic instead of a tonic a ctivity of the tibialis anterior muscle, and an improved activation pattern of the left rectus and biceps femoris muscles. Conclusions: The present study demonstrated that the injection of Botulinum toxin A resulted in a more mature muscle activation pattern of CP children . Most of the children walked more plantigrade and erect, the functional ga it parameters, however, did not change.