Comparing two randomized deep brain stimulation trials for Parkinson's disease

Area of Science:

• Neurology
• Neurosurgery
• Medical Technology

Background:

• Deep brain stimulation (DBS) of the subthalamic nucleus is a treatment option for Parkinson's disease.
• Randomized studies have compared DBS with medical management, but outcome measures vary.
• Two major studies, the German LQ study and the US VA/NINDS trial, provide data for comparison.

Purpose of the Study:

• To compare outcomes between the LQ study and the VA/NINDS trial for subthalamic nucleus DBS in Parkinson's disease.
• To identify factors contributing to differences in reported outcomes between these two large studies.

Main Methods:

• Analysis of "as-treated completers" from both studies (LQ: 69 patients, VA/NINDS: 125 patients).
• Utilized 6-month follow-up data for comparison.
• Data analyzed using SAS software by biostatisticians from involved institutions and Medtronic.

Main Results:

• Pre-DBS demographics differed, with higher levodopa responsiveness (LDR) in the LQ study.
• LQ subjects showed greater improvements in motor function (UPDRS-III) and activities of daily living (ADLs) post-DBS.
• No significant differences in medication reduction or non-ADL quality of life improvements were observed.
• When stratified by LDR, "full responders" showed similar motor improvements with DBS in both studies.

Conclusions:

• Patient selection criteria, especially preoperative levodopa responsiveness (LDR), are critical determinants of motor and quality of life outcomes in DBS for Parkinson's disease.
• Differences in LDR between study populations likely explain the observed outcome variations.