Development of an Instrumented System to Measure Mobility in Parkinson's Disease

The specific aims of the study: 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. Aim II. To develop an objective, composite iTUG mobility score. We recently demonstrated that iTUG metrics are more sensitive in distinguishing mobility performance between people just diagnosed with PD from age-matched controls than traditional clinical tests. In this proposal, we will develop a composite mobility score from the iTUG gait and postural parameters most responsive to severity of PD and to the change from the levodopa ON and OFF states. The composite score will be calculated using statistical models that optimize differences in performance between 75 subjects with PD in the ON and OFF levodopa state. Aim III. To prospectively determine the reliability, validity and responsiveness of the iTUG mobility score. We will perform a prospective study with 60 patients with PD that compares standard clinical measures of postural instability and gait difficulty mobility (PIGD items from the Unified Parkinson's Disease Rating Scale (UPDRS) and TUG stop-watch scores) with our new iTUG mobility score in the OFF and ON levodopa states. We hypothesize that the iTUG will have good test-retest reliability, be significantly correlated with standard clinical measures and fall history and be more responsive to dopaminergic state than current mobility tests used in clinical trials. This project will develop, produce, and test a novel clinical balance and gait assessment tool, the instrumented Timed Up and Go test (iTUG) using our new, wearable, inertial sensors and our new clinical trial data management server that automatically transmits, stores, and analyzes data collected with the iTUG. By automatically providing a more sensitive, accurate, and comprehensive method to test balance and gait, clinical trials to improve mobility in patients with Parkinson's disease and other neurological disorders will be significantly more effective and efficient.