Biphasic Levodopa-Induced Freezing of Gait in Parkinson's Disease.

The relation between freezing of gait in Parkinson's disease and levodopa is complex. Here, we describe a new phenotype of freezing of gait, namely levodopa-induced freezing of gait with a biphasic pattern. Our observation supports the idea that freezing of gait might emerge because of a mismatch between cognitive/limbic loops and motor loops involved in gait control. Moreover, it underscores the importance of assessing the influence of dopaminergic medication in daily clinical practice, including objective assessment in all three dopaminergic states. The possibility of biphasic freezing will only emerge after such a comprehensive evaluation, and will have immediate therapeutic consequences.