Our main goal is to develop an instrument (core assessment protocol, CAP) that will provide the movement disorder centers around the world with a common evaluation program for Parkinson's disease (PD) and progressive supranuclear palsy (PSP) patients selected for pedunculopontine nucleus area (PPNa) deep brain stimulation (DBS), and recommendations for intra-operative targeting and post-operative management. Our long-term goal is to use the developed CAP for two multicenter clinical trials with PPN area DBS in PD and PSP patients.
We are an international Working Group (PPN DBS Working Group) comprehensive of 35 colleagues with experience in PPN DBS (neurologists, neurosurgeons, neurophysiologists, gait specialists, bioengineers, and neuropsychologists).
Postural instability and gait difficulties (PIGD) are highly debilitating symptoms that affect almost all patients with advanced PD. These symptoms emerge much earlier within the course of the disease for PSP. These PIGD symptoms generally do not respond well to medical treatment and can be improved temporarily by subthalamic nucleus and globus pallidus internus DBS prior to axial disease progression. The stimulation of the PPNa has recently been investigated as an alternative DBS target site; however, the initial results were mixed. These results have raised a number of issues regarding patient selection, target localization, optimal parameter settings and outcome measures. We believe that it is now the right time to focus on possible benefits and limits coming from the current literature and worldwide experience on PPN DBS.
Our members are currently working on the first draft of the CAP, addressing different sets of questions/answers on the most relevant PPN DBS related issues. The questionnaire involves patient selection (inclusion/exclusion criteria), management and evaluation (short and long term), surgery procedures and targeting (intra-operative recording and stimulation, appropriate imaging, adequate surgical hardware). The adopted methodology consists of answering the questionnaire by using: a) a systematic and thorough review of available evidence-based studies, b) drawing conclusions and c) providing recommendations.