The PPN is an important output target of the STN. It has also been implicated in the mediation of gait and posture; aspects of PD which are not well treated by DBS of the STN or GPi (14). Aziz et al. (18,19) published a report of low-frequency PPN stimulation in primates that improved symptoms of akinesia. Mazzone et al. reported two patients, with PD causing significant gait disturbance, who underwent implantation of PPN DBS electrodes. They demonstrated the safety of the procedure and the ability of low-frequency intraoperative stimulation to improve selective elements of the Unified Parkinson's Disease Rating Scale (UPDRS) motor scale (20). A study by Plaha and Gill (21) also reported two patients who underwent PPN DBS implantation and demonstrated that both patients had improvements both in UPDRS motor scores and in scales measuring balance and gait. These reports will need validation by larger series and prospective trials, but there seems to be promise to this novel target. As our knowledge of the subcortical circuitry underlying motor regulation improves, DBS may be tailored to the pathologies of individual patients; perhaps selecting or adding the PPN target in gait-predominant PD.
Was this article helpful?