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DOI: 10.1055/s-2008-1072809
Levodopa improves procedural motor learning in chronic stroke patients
Objective: Stroke is a leading cause of motor disability. Recovery of motor function after stroke often remains incomplete despite physiotherapy. This study was designed to test the hypothesis that administration of dopamine (DA) precursor levodopa improves procedural motor learning in patients with residual motor deficits in the chronic phase after stroke (> one year after stroke). Procedural motor learning is defined as the ability to acquire novel movement patterns gradually through practice.
Design: A double-blind, placebo-controlled, randomized cross-over design was used.
Setting: Department of Neurology, University of Muenster, Germany.
Patients: Eighteen stroke patients (age range: 53–78 years, 5 female).
Interventions: Patients received three doses of levodopa (100mg levodopa + 25mg carbidopa) or placebo prior to one session of procedural motor learning.
Main Outcome Measures: Procedural motor learning using the paretic hand, assessed by a modified version of the serial reaction time (SRT) task with a probabilistic sequence. Primary outcome measure was the difference in reaction times (RTs) between random and sequential elements.
Results: Levodopa significantly improved our primary outcome measure, procedural motor learning, compared to placebo (p<0.05). Reaction times to random elements, analysis of error rates, psychophysical assessments, as well as performance in a simple motor task were comparable between conditions, indicating that better learning under levodopa was not due to differences in response styles, arousal, mood, or motor reaction time, but that levodopa modulated learning.
Conclusions: Our results demonstrate that levodopa may improve procedural motor learning in chronic stroke patients, in line with our hypothesis. These findings suggest that this interventional strategy in combination with customary rehabilitative treatments could significantly improve outcome of neurorehabilitation in the chronic stage after stroke.