J. Wissel

The present study was performed to assess dose-response relationships of local botulinum toxin A (BtxA) treatment in children and teenagers with spastic gait due to cerebral palsy (CP) in a randomized, double-blind study employing a "high-dose" (200 units Botox per leg) and a "low-dose" (100 units Botox per leg) treatment arm in 33 patients with CP. Response parameters included changes in muscle tone assessed by the Ashworth scale at knee joint, range-of-motion (ROM) measurements at knee and ankle joint, objective analysis of longitudinal gait parameters as well as subjective assessments of improvement. Patients in the "high-dose" arm received 40-80 units Botox/muscle versus 20-40 units Botox/muscle in the "low-dose" group. Patients in both treatment arms showed significant improvement of Ashworth score (p<0.001) and ROM (p<0.01), while gait analysis revealed significant increase in gait velocity (p<0.01) and stride-length (p<0.001) over baseline. Subjects in the "high-dose" group showed significantly greater improvement on objective response measurements compared to "low-dose" patients. Also, children aged 7 years or less had greater functional benefit compared to the subgroup of patients older than 7 years. Incidence and severity of side-effects were similar in both treatment groups. The present study demonstrated dose-dependent functional improvement of dynamic deformities and spastic gait pattern in children and young adults with CP treated with local injections of botulinum toxin. A dose of 200 units Botox per leg distributed to 4 or 5 muscle bellies per leg is superior compared to 100 units Botox per leg without significantly affecting the risk of side-effects.

Nicotine has been reported to have positive effects on motor performance in patients with Parkinson's disease. In this study, motor performance was evaluated in 16 patients with idiopathic Parkinson's disease during a practical off-period using the motor part of the Unified Parkinson's Disease Rating Scale after 12 hours' exposure to a transdermal patch containing 35 mg nicotine or placebo. The study was performed using a double-blind crossover design. In contrast to previous reports, nicotine exposure was followed by a worsening of symptoms compared with placebo. A negative response to subthreshold dopaminergic stimulation, resulting from an inhibitory effect of low striatal dopamine concentrations acting on a subset of dopamine receptors, might possibly account for this finding.