A lead extension useful in deep brain stimulation treatment includes a body portion having a distal end and a proximal end, wherein the proximal end receives a stimulation signal from a generator. A lead interface is disposed at the distal end to send the stimulation signal to a brain stimulation lead. The lead extension also includes a sensor interface disposed at the distal end to receive an input signal from a sensor that is detached from the stimulation lead and send the input signal to the generator.