Long-duration response to levodopa in patients with advanced Parkinson disease treated with subthalamic deep brain stimulation.

Background: Long-duration response (LDR) to levodopa is supposed to decrease with Parkinson disease (PD) progression, but direct observation of this response in advanced PD has never been performed.
Objective: To study the LDR to levodopa in patients with advanced PD treated with subthalamic deep brain stimulation (DBS).
Design and Setting: We studied 30 consecutive patients with PD who underwent subthalamic DBS. One group had no antiparkinsonian treatment since surgery (no-levodopa group), whereas medical treatment had to be reinitiated in the other group (levodopa group).
Main Outcome Measure: Motor subscale score of the Unified Parkinson's Disease Rating Scale.
Results: Compared with preoperative assessment, evaluation 6 months postoperatively with DBS turned off for 3 hours found a worsening of the motor subscale score of the Unified Parkinson's Disease Rating Scale in the no-levodopa group. This worsening being absent in the levodopa group, it probably reflected the loss of the LDR to levodopa in the no-levodopa group. When DBS was turned on, postoperative motor subscale scores of the Unifid Parkinson's Disease Rating Scale in both groups were similar to preoperative scores while receiving medication, suggesting that subthalamic DBS compensated for the short-duration response and LDR to levodopa.
Conclusions: Our results suggest that the LDR to levodopa remains significant even in advanced PD, and that subthalamic DBS compensates for the short-duration response and LDR to levodopa.