1. A method comprising: delivering a therapy from a medical device to a patient to treat a movement disorder; monitoring gait of the patient based on a signal generated by a sensor that varies as a function of patient activity; and for each of a plurality of therapy parameter sets used by the medical device to control delivery of the therapy to the patient, determining a value of at least one metric based on the gait of the patient during delivery of the therapy by the medical device according to the therapy parameter set.