Deep Brain Stimulation of Pedunculopontine Nucleus for Postural Instability and Gait Disorder After Parkinson Disease: A Meta-Analysis of Individual Patient Data

Background: Postural instability and gait disorder (PIGD) in Parkinson disease (PD) has been a great challenge in clinical practice because PIGD is closely linked to major morbidity and mortality in PD. Pedunculopontine nucleus (PPN) has been considered as a potential promising target for deep brain stimulation (DBS) in the treatment of PIGD. A meta-analysis of individual patient data was performed to assess the effects of PPN DBS on PIGD in patients with PD and explore the factors predicting good outcome.

Methods: According to the study strategy, we searched PubMed, Embase, and the Cochrane Central Register of Controlled Trials, and other sources. After searching the literature, 2 investigators independently screened the literature, assessed the quality of the included trials, and extracted the data. The outcome measures included PIGD, freezing of gait, and falling in PD. Then, individual patient data were incorporated into SPSS software for statistical analyses across series.

Results: Six studies reporting individual patient data were included for final analysis. PPN DBS significantly improved PIGD as well as freezing of gait and falling after PD, which was depending on the duration of follow-up and types of outcome measures. In addition, patient age, disease duration, levodopa-equivalent dosage, and the choice of unilateral or bilateral stimulation were similar in groups of patients with PD with or without improvement in PIGD after PPN DBS.

Conclusions: Our study provides evidence that PPN DBS may improve PIGD, which should be interpreted with caution and needs further verification before making generalization of our results.