2022-2023 Pilot Project Grant Awardees

Victor Duenas, Ph.D.  

Syracuse University, College of Engineering and Computer Science, Mechanical and Aerospace Engineering

Operant Conditioning of Loading Response During Locomotion in People After Stroke

Stroke survivors experience low weight-bearing capacity and muscle weakness that impair their walking ability. The ankle joint and soleus muscle are critically important for locomotion, as they
store mechanical energy throughout the stance phase, leading to the burst of plantarflexor power at push-off for propulsion. However, plantarflexor activation and propulsive force are diminished in the paretic leg. By enhancing the excitability of Ib pathways, propulsive soleus activity and resulting force generation can be improved after stroke. The objective of this project is to develop a control strategy to modulate the soleus loading response in the stance phase using a wearable robotic device during treadmill walking. This project characterizes the plantarflexors’ loading response to be exploited as a novel target of neuromodulation through operant conditioning to enhance ankle power and propulsion, which can improve gait function after a stroke.  Please visit the Bionics, Systems and Control Lab page for more information.  

John Kindred, Ph.D.                               

Medical University of South Carolina, College of Health Professions

Effects of tDCS on post-stroke fatigue and inflammation

Fatigue is a common condition after an individual has a stroke. While the negative impacts of post-stroke fatigue are well known, our knowledge of the causes of post-stroke fatigue and effective treatments for post-stroke fatigue are lacking. This pilot study will investigate the possible benefits of transcranial direct current stimulation (tDCS), which uses small electrical currents supplied by a 9-volt battery, to reduce post-stroke fatigue. Previous reports have suggested small electrical currents, like those provided by tDCS, can impact glial cell activity and inflammatory markers. These factors have been suggested to play a role in the development and severity of post-stroke fatigue and fatigue in other neurological conditions.

Thorsten Rudroff, Ph.D.

University of Iowa, Department of Health and Human Physiology, Integrative Neurophysiology Laboratory

tDCS Treatment of Post-COVID-19 Fatigue

For survivors of severe COVID-19, overcoming the virus is just the beginning of an uncharted recovery path. Persistent fatigue following several weeks after COVID-19 infection is common and independent of severity of initial infection (hospitalized and non-hospitalized patients).  There is a critical need to develop inexpensive, effective, safe, and rapid treatments for the persistent fatigue experienced by recovered COVID-19 patients. Without such treatments, these patients will continue to experience fatiguing symptoms that significantly reduce their quality of life. One possible treatment modality is transcranial direct current stimulation (tDCS) which uses weak currents applied to the scalp to alter the excitability of cortical neurons by changing their spontaneous firing rate. The goal of this application is to investigate the short- and long-term effects of multiple sessions of 4 mA M1 tDCS on persistent fatigue in recovered COVID-19 patients. Our central hypothesis is that tDCS will improve fatigue short- and long-term, and thus will improve quality of life in recovered COVID-19 patients. This study will also offer important new information on persistent fatigue resulting from COVID-19 and will help clinicians raise awareness of its involvement as a neurologic manifestation during post-infection recovery. Please visit the Integrative Neurophysiology Laboratory page for more information.

Andrew Quesada Tan, Ph.D.

University of Colorado, Boulder, Integrative Physiology

Examining the relationship between changes in corticospinal excitability and motor learning after acute intermittent hypoxia in persons with incomplete spinal cord injury

Spinal cord injury (SCI) results in sensorimotor deficits, leading to chronic mobility impairments and loss of functional independence. Modest breathing modest bouts of low oxygen (acute intermittent hypoxia; AIH), is a promising intervention shown to enhance motor recovery in persons with spinal cord injury, yet we do not fully understand why AIH augments walking performance. Increases in corticospinal excitability are commonly interpreted as a marker of gains in motor output (e.g., speed) but may not necessarily reflect changes in motor learning and movement energetics after AIH induced plasticity. The objective of this study is to examine if AIH elicits improvements in lower limb control by measuring the capacity to learn a walking adaptation task as well as the ability to modulate metabolic expenditure during the motor learning process. Discerning the behavioral relevance of corticospinal excitability in relation to motor learning and metabolic expenditure may be a key feature in optimizing neurorehabilitation interventions in persons with SCI. Please visit the Sensorimotor Recovery and Neuroplasticity Laboratory page for more information.

Amanda Therrien, Ph.D.

Moss Rehabilitation Research Institute, Albert Einstein Healthcare Network

Motor learning after cerebellar damage: The role of the primary motor cortex

Cerebellar damage causes the disabling movement disorder ataxia, which is characterized by impaired movement coordination affecting all body movements. In the arms, ataxia causes reaching movements with irregular, oscillating, and prolonged trajectory paths. Physical and occupational therapy are the main options for managing ataxia, but current therapy interventions for this disorder are complicated by cerebellar damage impairing an important form of motor learning, called adaptation, which normally keeps movement well calibrated. We have recently shown that PWCA can learn to correct their reaching movements if they instead employ reinforcement learning (RL). Although many PWCA learned optimally in RL conditions, we found variability across individuals: some learned more than others. While adaptation critically relies on cerebellar integrity, RL depends more heavily on excitatory plasticity in the primary motor cortex (M1). Cerebellar damage has been shown to increases inhibitory activity in M1, which may hamper the plasticity needed for RL. The repetitive transcranial magnetic stimulation protocols of continuous and intermittent theta burst stimulation have been shown to modulate inhibition in M1. This study will systematically test whether increased inhibition in M1 predicts RL capacity and whether modulating inhibition in M1 can alter RL capacity in PWCA. The results of this study will determine whether we can predict which PWCA may benefit most from RL interventions and whether we can maximize that benefit with neuromodulation. Please visit the Sensorimotor Learning Laboratory page for more information.