Research at PTRS
 | Investigator: Larry Forrester, PhD |
Human Motor Performance Laboratory
The Human Motor Performance Laboratory (HMPL) is located within the Baltimore Veterans Affairs Medical Center that is contiguous with the University of Maryland School of Medicine and Medical Center. The broad thrust of our work is in the area of Neurorehabilitation with a focus on developing interventions aimed at restoring motor functions after neurological diseases such as stroke. The lab supports several studies investigating effects of exercise therapies on motor control and biomechanics of gait and balance. These include comparisons of different treadmill training approaches in individuals with hemiparetic gait, the use of resistance training in conjunction with lower extremity robotics to improve mobility and balance, and the development of lower extremity robotic therapies in the subacute and chronic phases after stroke. We also use electroencephalography (EEG), functional magnetic resonance imaging (fMRI), diffusion tensor imaging (DTI), and transcranial magnetic stimulation (TMS) to probe the central nervous system plasticity in response to these intervention approaches. Emerging collaborations include a new focus on the role of neurocognitive processes on motor learning.
Grant Support
Source: VA RR&D Center of Excellence: Task-oriented exercise and robotics in neurological disease, B3688R (PI Richard Macko)
Title: Modular Lower Extremity Robotics Assisted Exercise after Stroke
Role: Principal Investigator
Period: 2005-2010
Source: NIH P30 AG028747 (PI Andrew Goldberg) University of Maryland Claude D. Pepper Older Americans Independence Center
Title: Neuromotor Function Core (Core 2)
Role: Co-Investigator
Period: 2006-2011
Source: NIH P30 AG028747 (PI Andrew Goldberg) University of Maryland Claude D. Pepper Older Americans Independence Center, Pilot Grant
Title: Impedance Controlled Ankle Robot Training after Stroke: A Comparison of Bilateral Performance-based vs. Unilateral Passive Approaches
Role: Principal Investigator
Period: 2008-2009
Source: VA RR&D Center of Excellence: Task-oriented exercise and robotics in neurological disease, B3688R (PI Richard Macko)
Title: Human Performance & Neural Plasticity Core
Role: Principal Investigator
Period: 2005-2010
Source: VA RR&D Center of Excellence: Task-oriented exercise and robotics in neurological disease, B3688R (PI Richard Macko)
Title: Adaptations in cortical function induced by short-term robot-assisted training of foot movements in chronic stroke survivors
Role: Co-Investigator
Period: 2008-2009
Current Projects
Rehabilitation robotics for the lower extremity
Under the auspices of the VA Exercise & Robotics Center of Excellence (MERCE), and in collaboration with colleagues at MIT, we have developed an ankle robot for use with individuals who have hemiparesis after stroke. This project follows over a decade of studies at the University of Maryland and the Baltimore VA that have investigated the use of treadmill exercise training to show that gait function and fitness can be improved even years after a stroke. Furthermore, we have used fMRI and TMS in these studies to provide evidence of experience based neuroplasticity. Anklebot was designed to address deficiencies in paretic ankle contributions in walking and in dynamic balance control. It can be used in the functional contexts of overground or treadmill gait training, as well as in seated or recumbent positions for isolated training of ankle motor control. The Anklebot is programmable to allow guided movements, resistive movements, and even passive measurement of ankle position and net torque. The guided movements may either supply pre-determined torques, or they can be provided only when the user is not moving to the designated target location. Current projects investigate: the effects of 6-weeks of seated visuomotor training on paretic ankle impairments and gait function in subjects with chronic stroke, fMRI of brain activation during ankle motor tasks pre- and post- Anklebot training, the effects of Anklebot training on dynamic balance control during gait initiation in subjects with stroke, and the development of bedside protocols for using Anklebot during subacute hospitalization post-stroke.Cortical neurophysiology, neuroplasticity, and motor control
Our prior results provide evidence that hemiparetic knee movements elicit significant fMRI changes in brain activity after six-months of treadmill exercise training. New activity includes brainstem areas in vicinity of bilateral red nucleus and reticular formation in circled areas 3 & 4. (Stroke, 2008).
More recently we have used EEG to look at the brain activity associated with the type and quantity of sensory information required in knee extension tasks (Exp. Brain Res., 2007). Group-averaged head plots of the movement related cortical potentials (MRCP) at -1.5 and -0.5 seconds prior to movement onset show greater and prolonged cortical activity when proprioceptive and visual task constraints are combined (bottom row). Visual only and proprioceptive only conditions (rows 2& 3) yield less activity than the combined condition, but they exceed levels recorded in unconstrained movements (top row). Further analyses also show an increase in theta band spectral parameters in prefrontal cortices during the more complex processing load, suggesting a shift to greater attentional processing. These methods are now being applied to study the effects of short- and long-term cortical responses to Anklebot training in individuals with hemiparesis. The aim is to investigate the time course of motor learning during exposure to a novel therapy that utilizes visual and proprioceptive feedback during practice. A similar approach will be applied to study bilateral arm training with auditory cueing.
Collaborations
University of Maryland School of Medicine
Christopher Bever, MD
Alison Cernich, PhD
Ron Goodman, PhD
Charlene Hafer-Macko, MD
Fred Ivey, PhD
Richard Macko, MD
Sandy McCombe Waller, PT, PhD
Mark Rogers, PT, PhD
Mary Rodgers, PT, PhD
Anindo Roy, PhD
Alice Ryan, PhD
Jill Whitall, PhD
Johns Hopkins University
Dan Hanley, MD
University of Zurich, Zurich, Switzerland
Andreas Luft, MD
Massachusetts Institute of Technology
Neville Hogan, PhD
H. Igo Krebs, PhD
Lab Personnel and Staff
Robert Asbury, Research Assistant
Jessica Hammers, Study Coordinator
Ira Khanna, Graduate Assistant
Wei Liu, Graduate Assistant
Jaime Lush, Lab Manager/Research assistant
Recent Publications
- Luft, AR, McCombe-Waller, S, Forrester, LW, Smith, GV, Whitall, J, Macko, RF, Schulz, JB, & Hanley, DF. (2004). Lesion location alters brain activation in chronically impaired stroke survivors. Neuroimage, 21, 924-935.
- Harris-Love, M, Macko, RF, & Whitall, J., & Forrester, LW. (2004). Improved Hemiparetic Muscle Activation in Treadmill versus Overground Walking. Neurorehabilitation and Neural Repair 18, 154-160.
- Luft, A.R., McCombe-Waller, S., Whitall, J., Forrester, L.W., Macko, R.F., Sorkin, J.D., Schultz, J.B., Goldberg, A.G., & Hanley, D.F. (2004). Repetitive bilateral arm training and motor cortex activation in chronic stroke. JAMA 292, 1853-1861.
- Haeuber, E, Shaughnessy, M, Forrester, LW, Coleman, KL, Macko, RF. (2004) Microprocessor-Linked Accelerometer Monitoring of Home and Community Based Ambulatory Activity after Stroke. Arch. Phys Med & Rehab 85:1997-2001.
- Luft, A.R., Forrester, L., Macko, R.F., McCombe-Waller, S., Whitall, J., Villagra, F., Hanley, D.F. (2005). Brain activation of lower extremity movement in chronically impaired stroke survivors. Neuroimage, 26, 184-194.
- Macko, R.F., Ivey, F. M., Forrester, L.W. (2005). Task-Oriented Aerobic Exercise in Chronic Hemiparetic Stroke: Training Protocols and Treatment Effects. Topics in Stroke Rehabilitation 12; 1: 45-57.
- Macko, RF, Ivey, F., Forrester, L.W., Hanley, DF, Sorkin, J.D., Katzel, L. I., Silver, KH, Goldberg, A.P. (2005).Treadmill Training Improves Fitness and Ambulatory Function in Chronic Stroke Patients. Stroke 36: 2206-2211.
- Forrester, LW, Hanley, DF, Macko RF. (2006). Effects of treadmill training on TMS-induced excitability to quadriceps after stroke. Arch. Phys Med & Rehab., Feb; 87 (2): 229-234.
- Mizelle C, Rodgers M, Forrester L. (2006). Bilateral foot center of pressure measures predict hemiparetic gait velocity. Gait Posture 24(3):356-63.
- Patterson SL, Forrester LW, Rodgers MM, Ryan AS, Ivey FM, Sorkin JD, Macko RF. (2007). Determinants of walking function after stroke: Differences by deficit severity. Arch Phys Med Rehabil. 88(1):115-119.
- Wheaton LA, Mizelle, C, Forrester LW, Bai O, Shibasaki H, Macko RF. (2007) How does the brain respond to unimodal and bimodal sensory demand in movement of lower extremity? Exp. Brain Res 180: 345-354.
- Wheaton LA, Carpenter M, Mizelle JC, Forrester LW (2008). Preparatory Band Specific Premotor Cortical Activity Differentiates Upper and Lower Extremity Movement. Exp Brain Res. 184: 121-126.
- Luft A, Macko R, Forrester L, Goldberg A, Hanley DF. (2008). Post-stroke exercise rehabilitation: What we know about retraining the motor system and how it may apply to retraining the heart. Cleveland Clinic Journal of Medicine 75 Supplement 2, S83-86.
- Patterson SL, Rodgers MM, Macko RF, Forrester LW. (2008). Effect of treadmill exercise training on spatial and temporal gait parameters in individuals with chronic stroke. JRRD 45 (2): 221-228.
- Forrester LW, Wheaton LA, Luft AR. (2008). Exercise-mediated Locomotor Recovery and Lower Extremity Neuroplasticity after Stroke. JRRD 45 (2): 205-220.
- McCombe Waller S, Forrester LW, Villagra F, Whitall J. (2008). Intracortical inhibition and facilitation with unilateral dominant, unilateral nondominant and bilateral movement tasks in left and right handed adults. J. Neurological Sciences 296: 96-104.
- Luft AR, Macko RF, Forrester LW, Villagra F, Ivey, F, Sorkin JD, Whitall J, McCombe-Waller S, Katzell L, Goldberg AP, Hanley DF. (2008). Treadmill exercise activates subcortical neural networks and improves walking after stroke: a randomized controlled trial. Stroke, published online Aug. 28, 2008. DOI: 10.1161/STROKEAHA.108.527531.
- Wheaton LA, Villagra F, Hanley DF, Forrester LW. (2008). Reliability of TMS Motor Evoked Potentials in Quadriceps of Subjects with Chronic Hemiparesis after Stroke. J Neurological Sciences. http://dx.doi.org/10.1016/j.jns.2008.09.012
- Roy A, Krebs HI, Williams D, Bever C, Forrester L, Macko R, Hogan N. (accepted). Robot-Aided Neurorehabilitation: A Novel Robot for Ankle Rehabilitation. Special Issue on Rehabilitation Robotics of the IEEE Transactions on Robotics.
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