Enhancing Control of Upper Extremity Movements Post-Stroke

Related Experiments | Key Publications | Future Investigations | Noteworthy Equipment | Collaborators | Research Support

Sensations of arm position and movement are critical for accurate and efficient planning and control of movement. Unfortunately, deficits in limb sensation are experienced by almost 50% of stroke survivors, ultimately leading to decreased use of the contralesional arm. The NeuroMotor Control Laboratory seeks to understand how the stroke-injured brain controls upper extremity movements after stroke and use that knowledge to develop "sensory augmentation" technologies to enhance reach and object manipulation with the more-affected arm and hand.


Related Experiments 

  • Coordination of Limb Posture & Movement
  • Sensory Augmentation via Supplemental Vibrotactile Kinesthetic Feedback

This project analyzes disordered control of posture and movement during reaching and stabilization tasks in patients with stroke. Our prior work has shown that normal reaching requires control of both posture and movement, that these two components of the task are specified by different neural mechanisms, and that the coordination of posture and movement may be differentially impaired after stroke. Using a planar robot arm and novel EMG biofeedback methods, we seek to characterize stroke-related changes in the ability to maintain postural stability throughout the workspace via graded coactivation of antagonist muscles, and in the ability to execute accurate movements via the coordinated activation of synergistic muscles.

Investigators at the NMCL aim to develop wearable technologies that use vibrotactile stimuli to augment sensations of arm position and movement for survivors of stroke with sensory deficits in the upper-extremity. To do so, we must first understand how best to encode useful information within vibrotactile stimuli, where best on the body to apply those stimuli, and how best to train people to use the novel supplemental feedback. We have performed several experiments exploring vibrotactile perception, as well as experiments exploring how readily people can interpret different kinds of information encoded within vibrotactile stimuli. We have used that knowledge to study how people may learn to use supplemental vibrotactile feedback to improve the accuracy and efficiency of actions ranging in complexity from simple 1-Dimensional (1-D) reaches to complex 3-D reach-to-grasp actions. We are also investigating the extent to which stroke impacts how survivors can use different forms of augmentation to improve the accuracy and efficiency of their reach-to-grasp actions.


Key Publications

Scheidt RA, Stoeckmann T (2007) Reach adaptation and final position control amid environmental uncertainty following stroke. J. Neurophysiol. 97: 2824-2836.

Scheidt RA, Ghez C (2007) Separate adaptive mechanisms for controlling trajectory and final position in reaching. J. Neurophysiol. 98: 3600–3613.

Mrotek LA, Bengtson M, Stoeckmann T, Botzer L, Ghez CP, McGuire J, Scheidt RA (2017) The Arm Movement Detection (AMD) Test– a fast robotic test of proprioceptive acuity in the arm.  J Neural Eng Rehab 14:64.

Krueger A, Giannoni P, Casadio M, Scheidt RA (2017) Supplemental vibrotactile feedback control of stabilization and reaching actions of the arm using limb state and position error encodings. J Neural Eng Rehab 14:36.

Risi N, Shah V, Mrotek LA, Casadio M, Scheidt RA (2019) Supplemental vibrotactile feedback of real-time limb position enhances precision of goal-directed reaching. J Neurophysiol 122: 22–38.

Shah VA, Casadio M, Scheidt RA, Mrotek LA (2019) Vibration propagation on the skin of the arm. Appl. Sci 9: 4329.

Shah V, Casadio M, Scheidt RA, Mrotek LA (2019) Spatial and temporal influences on discrimination of vibrotactile stimuli on the arm. Exp Brain Res 237: 2075–2086.

Ballardini G, Krueger A, Giannoni P, Marinelli L, Casadio M, Scheidt RA (2021) Effect of short-term exposure to supplemental vibrotactile kinesthetic feedback on goal directed movements after stroke: a proof of concept case series. In press, Sensors.


Future Investigations 

The NMCL will seek to compare the utility and effectiveness of various vibrotactile encoding schemes and determine which lead to better long-term training results after stroke.


Noteworthy Equipment

  • Vibrotactile Displays
  • Planar 2 degree-of-freedom Strength and Coordination Robot
  • NDI Optotrak 3020 motion analysis system
  • Bilateral gravitational support arm exoskeleton



Not Pictured

Erin Corrigan

Rocky Mazorow

Ella Pomplun

Ramsey Rayes

Valay Shah, Ph.D.

Ashiya Thomas


Research Support

This work is sponsored by the National Institutes of Health NICHD grants 2R15HD093086, "Augmenting kinesthetic feedback to improve hemiparetic arm control after stroke, and 1R01HD053727, "Control of Arm Posture and Movement Following Stroke."  



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