Low- and high-dose botulinum toxin A treatment: a retrospective analysis.

Upper limb botulinum toxin A doses in children are empirical, determined by the size of the muscle, seeking to avoid excessive weakness and deterioration of function. This study reports the effects and side effects of botulinum toxin treatment on upper limb impairment and function in 18 children with spastic or dystonic hyperactivity. A total of 54 treatments were divided into low-dose or high-dose groups according to the dose used for the target muscles. The outcome measurements included modified Ashworth Scale, passive range of movement, various grips, bimanual functions, movement pattern, House classification of upper extremity use, and subjective ratings of function and cosmetic appearance. In the functional goal group, children benefited in terms of reduction in muscle tone at elbow and wrist, and increase in passive wrist extension and House classification scores. A significant difference between the groups was observed in the House classification, favoring the low-dose group. In the nonfunctional goal group, a significant difference was detected in subjective parental cosmetic ratings, favoring the high dosage. Side effects were few and occurred mostly in the high-dose group. In conclusion, the use of higher doses in the spastic upper limb does not necessarily yield superior results compared with lower doses but increases the incidence of side effects.