A team of researchers has discovered a possible reason why L-dopa, the front-line drug for treating Parkinson's disease, loses efficacy and causes dyskinesia—involuntary, erratic muscle movements of the patient's face, arms, legs and torso—as treatment progresses. "Paradoxically, the exact therapy that improved the quality of life for tens of thousands of Parkinson's patients is the one that contributes to the rapid decline in quality of life over time," said Amal Alachkar, Ph.D. "L-dopa has been shown to accelerate disease progression through neural mechanisms that are not very well understood." L-dopa and other pharmacological treatments for Parkinson's are designed to replace...