Methylphenidate does not improve spasticity in patients with hereditary spastic paraplegia (HSP) – results of an open controlled trial.
Hereditary spastic paraplegia (HSP) is an inherited, degenerative genetically and clinically heterogeneous disorder which is characterized by a slowly progressive weakness and spastic paraparesis. Therapy for HSP mostly consists of physiotherapy and drug treatment for spasticity. Only symptomatic therapy is available.
As an amphetamine Methylphenidate influences many neurotransmitter including glutamate, serotonin and dopamine. A single case observation in our department where the spastic gait in a patient with HSP was improved and case reports about improvement of spasticity after intake of Methylphenidate prompted us to start an open trial on Methylphenidate in spasticity in 22 patients with HSP. Patients with HSP took methylphenidate over a 6 months period with a maximum concentration of 60 mg per day. 3-D Gait analysis, neurological examination including the modified "Ashworth Scale" and measurements of the central motor conduction time to the tibialis anterior muscle were performed at baseline, after 6 weeks and six month.
Regarding the most impaired gait parameters in HSP we found a small, but significant improvement of 11% in gait velocity after six weeks. This finding decreased to the baseline level after six month. We interpret this as a placebo effect. Other gait parameters were not influenced by methylphenidate in this trial. Neither the range of motion of the different joints (ankle, knee, hip) nor the step width, step length or step higth changed over the whole period. No change was found in the central motor conduction time to the tibialis anterior muscle or on clinical scores.
In methylphenidate failed to improve impaired gait parameters in patients with HSP and does not offer a conclusion, new therapeutic approach for the treatment of spasticity.