Aim I. To create a novel, commercially-available system for mobility assessment in clinical trials for Parkinson's disease. We have already developed a laboratory prototype system for the iTUG test, but the computer interface, sensors, and data management system are too cumbersome for use in clinical trials. In this proposal, we will create a robust, user-friendly clinical system for the iTUG test using wireless inertial sensors and a new user interface developed by a Portland start-up company, Automated Parkinson's Disease Monitoring (APDM), headed by a co-investigator. This mobility measuring system will be integrated with a new centralized data management server also developed by APDM, Inc. to support automatic data analysis and data organization for multi-site clinical trials. The feasibility of the new, clinical system will then be vetted by using it in a busy Movement Disorders Clinic.