Adaptive deep brain stimulation in Parkinson's disease.

With the introduction of adaptive deep brain stimulation (aDBS) for Parkinson's disease, new questions emerge regarding who, why, and how to treat. This paper outlines the pathophysiological rationale for aDBS, which provides real-time modulation of the stimulation amplitude based on subthalamic beta (range 13-30 Hz) activity and related physiomarkers. We review clinical evidence comparing aDBS with conventional DBS in terms of motor improvement, side-effect reduction, energy efficiency, and technical developments, including sensing-enabled device characteristics, stimulation algorithms, and potential clinical indications. We also discuss limitations, such as physiomarker variability, signal artifacts, and the absence of standardised programming protocols. Finally, we explore the readiness for clinical implementation and future directions, and estimate the scope of eligible patients. In our view, aDBS marks a fundamental change in approach from fixed stimulation towards physiomarker-guided neuromodulation. This evolution necessitates new infrastructure, clinician training, and real-world studies, but holds promise for more personalised and responsive treatment.