The disclosure is directed to a chronic implantable neurostimulator that supports trial and chronic modes of operation. The implantable neurostimulator can alternatively include one or more sensors that may or may not function differently in trial and chronic modes. In particular, the device is designed to be used as both a trial neurostimulator and a permanent, or chronic, neurostimulator. A trial neurostimulation period is generally desired to evaluate the efficacy of the therapy. A percutaneous or implantable trial neurostimulator is used for the trial neurostimulation period. In most cases, the trial period is successful, in which case the trial stimulator is explanted and replaced with a permanent, i.e., “chronic,” implantable stimulator. In accordance with the disclosure, an implantable neurostimulator supports both trial neurostimulation and chronic neurostimulation in the event trial stimulation is successful. In this manner, the additional surgery ordinarily required for replacement of the trial stimulator can be avoided. Instead, the implanted neurostimulation device remains implanted and is reconfigured to transition from trial stimulation to chronic stimulation.
