Deep brain stimulation of the subthalamic nucleus: All that glitters isn't gold?

With the silver anniversary of deep brain stimulation (DBS) behind us, this would seem to be a good juncture to consider its successes and unanswered questions. Bilateral subthalamic nucleus (STN) stimulation has changed the clinical perspective of several thousand Parkinson's disease (PD) patients worldwide. A recent reappraisal animates the field with strong arguments in favor of an anticipation of the stereotactic approach in patients with as little as 5 to 6 years of disease history if they manifest motor complications. From what was once a no-choice option, STN-DBS is now becoming more and more attractive to neurologists dealing with movement disorders. Despite the development of new pharmacological treatment and renewed rehabilitation programs able to modify the severity of drug-related complications, a resurgence of stimulation therapy reminiscent of an old era of medicine with an attendant blinkered mindset has emerged. Yet, the DBS-mediated effects are modest on critical aspects such as gait impairment and extremely variable depending on the clinical phenotype and individual clinical profile. Hence, the indication for DBS should become more, and not less, individually tailored. Those physicians considering deep brain stimulation (DBS) as a therapeutic option need to evaluate results beyond short-term quality of life, giving the correct weight to the direct and indirect costs over the longer term as well as to life prognosis. Unequivocal recourse to early-stimulation surgery necessitates investigations not limited to a mere comparative assessment versus drug-mediated benefits, but instead showing evidence of a clear degree of disease-modifying effect or a rescue of basal ganglia plasticity.