Targeted Motor Learning to Improve Gait for Individuals With Parkinson Disease

The purpose of this research study is to determine how training to step with a metronome on both a treadmill, as well as overground, will influence the way that people with Parkinson disease walk. Using metronomes is commonly used in clinics, but the investigators will be using a combination of slow and fast frequencies to alter the way that people walk. The use of a slower frequency metronome on the treadmill is intended to help participants take larger steps. The use of a faster frequency metronome while walking overground is intended to help participants take faster steps.This will take place over 12 training sessions. Each session will be about an hour. It will include some walking tests and pictures of the brain (using MRI) before and after training.

Inclusion Criteria: * idiopathic Parkinson's disease (Hoehn and Yahr Stage 2-3) * self-report the ability to walk uninterrupted for 10 minutes both overground and on a treadmill without therapist assistance * comfortable gait speed \> 0.4 m/s and \< 1.2 m/s * normal (or corrected to normal \[i.e., hearing aid\]) hearing * deficits in gait continuity (e.g., shuffling, shortened strides, freezing, festination, bradykinesia, etc) based on observational gait analysis * Movement Disorders Society - Unified Parkinson Disease Rating Scale (MDS-UPDRS-III) item 10 ≥1 and \