The goal of our work is to investigate how the human nervous system controls movement in health and in neurological and neurodegenerative disease.

We employ kinematic, kinetic, electromyographic, videooculographic, and neuroimaging techniques to study the neural control of movement. In particular, we are interested in locomotor and postural control in movement disorders such as Parkinson disease (PD). We aim to better understand factors in Parkinson disease that may contribute to difficulties with motor function and adaptation.

Since PD is a progressive, neurodegenerative condition, it is important for us to examine how movement and quality of life change over time in this population. In addition, we are working to gain insight into the impacts and mechanisms of common interventions including physical activity, pharmacotherapy, and deep brain stimulation on locomotor deficits. These studies will improve our understanding of motor function in PD over the course of the disease, as well as help inform clinical recommendations and treatments for patients with PD.

Faculty Investigators

Gammon Earhart, PT, PhD, FAPTA
Ryan Duncan, PT, DPT, MSCI
Pietro Mazzoni, MD, PhD


Martha Hessler – Research Coordinator 
Kerri Rawson, PhD, MS – Senior Scientist 


Elinor Harrison, PhD – Postdoctoral Fellow
Adam Horin, MA – PhD Student
David May, PT, DPT – PhD Student
Lauren Tueth – DPT Student
Olivia Nicholls – DPT Student
Reilly Siepka – DPT Student

Current Research Studies

Walking and mHealth to Increase Participation in Parkinson Disease (WHIP-PD)
Funding Source: NIH R01HD092444

Identifying effective ways to improve function, slow decline and reduce disability is a high priority for people living with Parkinson disease and other chronic conditions. Regular participation in walking is essential to reduce disability and enhance participation in preferred life activities. However, people with chronic conditions are often sedentary, contributing to greater disability. The goal of this work is to determine the benefits of a walking program and cognitive-behavioral strategies delivered using mobile health technology for people with Parkinson disease over a sustained period of time

Freezing of Gait in PD
Funding Source: UL1 TR000448, Barnes Jewish Hospital Foundation

Freezing of gait, a sudden, unintentional stopping of ongoing walking, is a serious problem for many individuals with PD. Our studies use a variety of approaches including wearable sensors to detect freezing, kinematics to measure gait in people with and without freezing and functional magnetic resonance imaging to determine how brain activity and connectivity differ in individuals with PD with and without freezing of gait, and testing of novel interventions to reduce freezing.

Physical Therapy and Deep Brain Stimulation in Parkinson Disease
Funding Source: NIH K12055931

Deep brain stimulation (DBS) has become a more common surgical treatment for PD. Although DBS is effective for some PD symptoms, balance and gait problems remain. Investigators have not yet studied this specific population to determine if balance and gait may improve with physical therapy. The purpose of this study is to investigate the safety, feasibility, and preliminary efficacy of a physical therapy program for people with PD with DBS.

Novel Cueing Strategies to Improve Gait in PD
Funding Source: NIH R61 AT010753

Gait dysfunction in Parkinson disease (PD) is disabling and leads to reduced quality of life. Enhancement of walking through use of rhythmic auditory cues may be helpful, but we do not yet understand how people respond to different types of cues (external vs. self-generated), what factors predict responsiveness to cues, and what mechanisms underlie these responses. This work will provide a solid foundation of knowledge in these areas and could ultimately lead to the development of personalized cueing interventions to optimize gait for individuals with PD, thereby reducing disability and improving quality of life.

Parkinson Disease Clinical Subtypes: Validation, Clinical Utility and Biological Correlates
Funding Source: NIH R01NS097437

There is variability in clinical presentation and progression of PD. We aim to identify and validate PD clinical subtypes based on comprehensive motor, cognitive, and psychiatric evaluations. As part of a multidisciplinary team, our lab is specifically involved in assessing gait patterns and their potential as biomarkers for PD subtypes.

Investigations of Dementia in Parkinson Disease
Funding Source: NIH R01NS075321

Parkinson disease (PD) produces progressive motor and cognitive impairments leading to dementia in ~75% of patients after 10 years. This multimodal study will establish the time course of changes in a variety of biomarkers that is critical to design studies to slow PD progression and identify targets of engagement for new therapies. As part of a multidisciplinary team, our lab is specifically involved in assessing gait patterns and how they change with changes in cognitive function in people with PD.

Past Research Studies

  • Exercise and Parkinson’s: Comparing Interventions and Exploring Neural Mechanisms (NIH 1R01NS077959)
  • Oculomotor Control and Gait in Parkinson Disease (NIH 1R01HD056015)
  • Unveiling the Natural History of Mobility and Quality of Life in PD: Charting History of Progression (Davis Phinney Foundation and the Parkinson Disease Foundation)
  • Rotating Treadmill Training: Adaptation and Application (NIH 5K01HD048437)