Neuromotor channel capacity as an outcome and tracking measure in Parkinson´s Disease

Motion quality is an important issue in movement disorders. We have developed and extensively studied neuromotor channel capacity, derived in part from Fitts\´ Law, as an objective coordination measure. We now use it to characterize subjects receiving deep brain stimulation (DBS) therapy. NMCC was measured (different conditions, medications and stimulation "off" and "on") with performance capacity measurement instruments (Human Performance Measurement, Inc.) for upper and lower extremities (both sides), respectively. Four-limb NMCC was computed by multiplying each limb\´s NMCC (in bits/sec). Results indicate that this measure agreed well with the Unified PD Rating Scale (motor sub-scale) and was sensitive to DBS with several distinct patterns of response. One group exhibited best performance with just stimulation, while another was optimal with both medication and stimulation. In some cases, performance improved (over pre-surgery) to within normal limits. NMCC measurement provides an efficient, objective means for capturing one important aspect of DBS outcome and perhaps for optimal stimulator adjustment.