publications

2025

1. Article

   Interlimb training improves motor function in partial-hand but not necessarily transradial simulated prosthesis use

   Alterman, Bennett L, Ali, Saif, Keeton, Emily, Binkley, Katrina, Hendrix, William, Lee, Perry J, Johnson, John T, Wang, Shuo, Kling, James, and Wheaton, Lewis A

   2025

   Abs

   The development of empirical approaches for functional rehabilitation during the acute and subacute stages following upper limb amputation is needed. For persons with unilateral limb loss, interlimb training is a potentially attractive approach, as it may allow for the translation of learned function from the unaffected to affected side while awaiting prosthesis fitting. Persons with sound limbs performed simple and complex reach-to-grasp motor tasks using a body-powered transradial or partial-hand prosthesis simulator in a 5-day interlimb training paradigm. Prior work in a single-session paradigm found improvments in motor control with prosthesis simulators, with an especially strong effect in partial-hand device use. Here, we hypothesized that participating in interlimb training would result in improvements in motor control with the prostheses, particularly in partial-hand device use and during complex tasks. Overall …

2. Patent

   Prosthesis Simulator Devices and Methods

   Alterman, Bennett Leonard, Hendrix, William D, Johnson, John T, Lee, Perry J, and Wheaton, Lewis A

   2025

   Abs

   Prosthesis simulator devices including a first restraint configured to restrain one or more fingers of a wearer of the simulator, a second restraint configured to restrain a thumb of the wearer, and a plurality of artificial digits configured to move in a manner to simulate one or more prosthetic fingers and a prosthetic thumb of a prosthesis. The first restraint can be attached to a roof plate connected to a base plate and defining a dorsal side of the prosthesis simulator. The second restraint can be attached to a holster connected to the base plate on a palmar side of the prosthesis simulator. Also disclosed herein are methods of using the same.

2024

1. Article

   Grasp Posture Variability Leads to Greater Ipsilateral Sensorimotor Beta Activation During Simulated Prosthesis Use

   Alterman, Bennett L, Ali, Saif, Keeton, Emily, Binkley, Katrina, Hendrix, William, Lee, Perry J, Johnson, John T, Wang, Shuo, Kling, James, Gale, Mary Kate, and Wheaton, Lewis A

   2024

   Abs

   Motor behaviour using upper-extremity prostheses of different levels is greatly variable, leading to challenges interpreting ideal rehabilitation strategies. Elucidating the underlying neural control mechanisms driving variability benefits our understanding of adaptation after limb loss. In this follow-up study, non-amputated participants completed simple and complex reach-to-grasp motor tasks using a body-powered transradial or partial-hand prosthesis simulator. We hypothesised that under complex task constraints, individuals employing variable grasp postures will show greater sensorimotor beta activation compared to individuals relying on uniform grasping, and activation will occur later in variable compared to uniform graspers. In the simple task, partial-hand variable and transradial users showed increased neural activation from the early to late phase of the reach, predominantly in the hemisphere ipsilateral to …

2. Patent

   Prosthesis simulator devices and methods

   Alterman, Bennett Leonard, Hendrix, William D, Johnson, John T, Lee, Perry J, and Wheaton, Lewis A

   2024

   Abs

   2021-09-22 Assigned to GEORGIA TECH RESEARCH CORPORATION reassignment GEORGIA TECH RESEARCH CORPORATION ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: HENDRIX, WILLIAM D., ALTERMAN, BENNETT LEONARD, LEE, PERRY J., JOHNSON, JOHN T., WHEATON, LEWIS A.

2022

1. Article

   Partial-Hand Prosthesis Users Show Improved Reach-to-Grasp Behaviour Compared to Transradial Prosthesis Users with Increased Task Complexity

   Alterman, Bennett L., Keeton, Emily, Ali, Saif, Binkley, Katrina, Hendrix, William, Lee, Perry J., Wang, Shuo, Kling, James, Johnson, John T., and Wheaton, Lewis A.

   Journal of Motor Behavior Apr 2022

   Abs

   Approaches to improve outcomes after upperextremity amputation remain poorly understood. Examining prosthesis-use at different levels of loss elucidates motor control challenges. Non-amputated participants completed simple and complex reach-to-grasp actions using a body-powered transradial or partial-hand prosthesis simulator. We hypothesised that increased task complexity and participants using a partial-hand device would show greater functional adaptation compared to participants using a transradial device. Partialhand users demonstrated variable grasp postures and higher reach peak velocities in the complex, but not simple, task. All groups showed decreases in movement duration in the complex task, but only partial-hand users improved in the simple task. These behavioural changes suggest how device level and task may influence prosthesis-use, with relevance to amputation rehabilitation.

2. Article

   Alpha-Band Activity in Parietofrontal Cortex Predicts Future Availability of Vibrotactile Feedback in Prosthesis Use

   Johnson, John T., de Mari, Daniele, Doherty, Harper, Hammond, Frank L., and Wheaton, Lewis A.

   Experimental Brain Research Mar 2022

   Abs

   Prosthesis disuse and abandonment is an ongoing issue in upper-limb amputation. In addition to lost structural and motor function, amputation also results in decreased task-specific sensory information. One proposed remedy is augmenting somatosensory information using vibrotactile feedback to provide tactile feedback of grasping objects. While the role of frontal and parietal areas in motor tasks is well established, the neural and kinematic effects of this augmented vibrotactile feedback remain in question. In this study, we sought to understand the neurobehavioral effects of providing augmented feedback during a reach-grasp-transport task. Ten persons with sound limbs performed a motor task while wearing a prosthesis simulator with and without vibrotactile feedback. We hypothesized that providing vibrotactile feedback during prosthesis use would increase activity in frontal and parietal areas and improve grasp-related behavior. Results show that anticipation of upcoming vibrotactile feedback may be encoded in motor and parietal areas during the reach-to-grasp phase of the task. While grasp aperture is unaffected by vibrotactile feedback, the availability of vibrotactile feedback does lead to a reduction in velocity during object transport. These results help shed light on how engineered feedback is utilized by prostheses users and provide methodologies for further assessment in advanced prosthetics research.

3. Dissertation

   The Neurobehavioral Effects of Sensorimotor Dissonance During Observation and Execution with Upper-Extremity Prostheses

   Johnson, John Terry

   Mar 2022

   Abs

   The human ability to perform powerful, complex, and intricate actions using our hands is made possible by the hand’s 27 degrees of freedom, its rich sensory feedback, and our ability to observe and understand the actions of others. In the event of an upper-extremity amputation, not only are articulated biological structures lost, but also their available sensory feedback. While great advances have been made in prosthesis engineering, the rate of prosthesis use in upper-extremity amputees remains low. Those who choose to use a prosthesis only do so an average of 50% of the time they could use them. One proposed strategy to improve prosthesis use and acceptance is the provision of task-salient vibrotactile feedback. Studies have been conducted on the efficacy of vibrotactile feedback, but have largely focused on kinematics, leaving a dearth of knowledge regarding the neural effects of vibrotactile feedback. In …

2021

1. Article

   Neurorehabilitation in Adults With Traumatic Upper Extremity Amputation: A Scoping Review

   Rydland, Jake, Spiegel, Stephanie, Wolfe, Olivia, Alterman, Bennett, Johnson, John T, and Wheaton, Lewis A

   Neurorehabilitation and Neural Repair Dec 2021

   Abs

   Background Most of the current literature around amputation focuses on lower extremity amputation or engineering aspects of prosthetic devices. There is a need to more clearly understand neurobehavioral mechanisms related to upper extremity amputation and how such mechanisms might influence recovery and utilization of prostheses. Objective This scoping review aims to identify and summarize the current literature on adult traumatic upper limb amputation in regard to recovery and functional outcomes and how neuroplasticity might influence these findings. Methods We identified appropriate articles using Academic Search Complete EBSCO, OVID Medline, and Cochrane databases. The resulting articles were then exported, screened, and reviewed based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses for Scoping Reviews (PRISMA-ScR) guidelines. Results Eleven (11) studies met the study criteria. Of these studies, 7 focused on sensory involvement, 3 focused on neuroplastic changes post-amputation related to functional impact, and 1 study focused on motor control and learning post-amputation. Overall, these studies revealed an incomplete understanding of the neural mechanisms involved in motor rehabilitation in the central and peripheral nervous systems, while also demonstrating the value of an individualized approach to neurorehabilitation in upper limb loss. Conclusions There is a gap in our understanding of the role of neurorehabilitation following amputation. Overall, focused rehabilitation parameters, demographic information, and clarity around central and peripheral neural mechanisms are needed in future research to address neurobehavioral mechanisms to promote functional recovery following traumatic upper extremity amputation.

2018

1. Abstract

   Does Haptic Feedback Support Motor Learning With a Prosthesis? A Neurobehavioral Evaluation: F53

   Johnson, John, and Wheaton, Lewis

   Dec 2018

   Abs

   Prosthesis use poses a unique challenge. Following an upper extremity amputation, the patient loses motor, structural, and somatosensory functionality. Technological advances have had negligible impact on clinical outcome measures, and rejection rates of upper extremity prostheses remains high. One technological advance is to provide greater sensory feedback from the prosthetic limb to potentially support improved function. However, the question of whether enhancing sensory feedback from the prosthesis improves motor learning and control remains open. To address this question, we recruited healthy intact subjects (n= 18) to use a prosthesis simulator to perform a repetitive reach-and-grasp task involving 3 differently sized discs. The 3 different disc sizes were used to determine if participants could learn to adapt to the disc size during reach-to-grasp. Participants were supplied with vibrotactile feedback …