A medical device delivers a therapy to a patient. The medical device or another device may periodically determine an activity level or gait parameter of the patient, and associate each determined level or parameter with a current therapy parameter set. A value of at least one activity metric is determined for each of a plurality of therapy parameter sets based on the activity levels or parameters associated with that therapy parameter set. Whether the patient is currently experiencing or anticipated to experience gait freeze caused by their neurological disorder, such as Parkinson's disease, may also be determined. Gait freeze events may be associated with current therapy parameters and used to determine activity metric values. In some examples, the activity metric associated with certain therapy parameters may be presented to a user.