Neural-Machine Interface and Prosthetics

A neural-machine interface is a machine, such as a bionic limb, that has a connection with the wearer’s brain—in this case, the user’s limb nerves. Our prosthetics utilize a neural-machine interface that surgically reconnects amputated nerves to new muscle and skin sites. The nerves of these amputees are not physically connected to the machine; instead, the bionic prosthetic picks up electrical signals from the reinnervated muscles and small robots push and vibrate against the user’s skin containing the reintegrated nerves.

When an amputee thinks about moving their bionic limb, nerve impulses travel from their brain to the reintegrated nerve endings in their muscles. The mechanical components of the muscles generate electricity when they contract which acts like a biological amplifier; intensifying the nerve impulses so that they control the actions of the prosthetic.

The prosthetic is bidirectional, meaning that it also receives information and relays it back to the nerves. Tactors, or touch robots, are integrated into the limb. These robots send pressure and vibrations through the skin to communicate with their reintegrated nerves which provides information about the prosthetic limb to the user’s brain. The information includes the prosthetic’s movement in space, the shape of the hand’s grip, and the feel of objects that the hand is touching.

Prosthetic Embodiment

We study ownership and agency, and use these concepts to engineer prosthetics that cognitively and perceptually integrate with the user.

Ownership is the sense that one occupies their body, and that the parts of one’s body belong to them. In our research, we use physiologically relevant artificial touch to help amputees feel that their prosthetic limb is a naturally integrated part of their body.

Agency is the feeling that you are the author of your actions. We use perceptual illusions of movement that are coupled to the intended movement of a prosthesis to provide amputees a sense of agency over their devices.

Together the experience of ownership and agency combine to provide a more integrated sense of overall prosthetic embodiment. This provides the amputees with a clear feeling that their prosthetic limb is a natural part of their own body.

Functional Metrics for Humans with Bidirectionally Integrated Prosthetic Limbs: Upper Limb Sensory-Motor Integration Assessments

The Laboratory for Bionic Integration is working closely with Dr. Jacqueline Hebert, MD, FRCPC at the University of Alberta; and Dr. Jon Sensinger, PhD, PEng of the University of New Brunswick to develop a suite of metrics as sophisticated and effective as the devices that they assess. These tests help map system function, so that they may be used as tools to inform technology design, implementation, and translation. The metrics are designed to not have a ceiling effect so that comparisons can be made with able-bodied users. They are rooted in science (psychophysics, cognition/perception, and kinematics) yet they represent functional, real-world tasks that are clinically applicable to users of advanced upper limb sensory-motor integration technologies.

For more information on the Functional Metrics Suite, please see the Functional Metrics Development

Key Concepts

Sensory nervous system: The nerves responsible for gathering information from your senses
Neuroplasticity: The ability of the brain to reorganize
Embodiment: The feeling that the parts of your body belong to you
Authorship: The feeling that you are in control of your body’s actions
Cognitive engagement: Amputees perceive that their prosthetic limb is under their control, and a part of their body

Current Projects

Functional Metrics for Humans with Bidirectionally Integrated Prosthetic Limbs

We are working in conjunction with the University of Alberta and the University of New Brunswick on development and delivery of a suite of validated functional metrics for bi-directionally integrated advanced prosthetic limb systems. The metrics will be adaptable to both advanced and current standard-of-care prosthetics, clinically implementable with a minimum requirement of technological expertise to operate, flexible to account for numerous systems approaches, sensitive to system performance, and reflective of requirements for quantifying different control and feedback strategies.

Defense Advanced Research Project Agency (DARPA), Department of Defense, Contract # N66001-15-C-4015


P. D. Marasco, J. S. Hebert, J. W. Sensinger, D. T. Beckler, Z. C. Thumser, A. W. Shehata, H. E. Williams, K. R. Wilson. "Neurorobotic fusion of prosthetic touch, kinesthesia, and movement in bionic upper limbs promotes intrinsic brain behaviors." Sci. Robot. 6, eabf3368 (2021).

D. T. Beckler, Z. C. Thumser, J. S. Schofield, P. D. Marasco. “Reliability in evaluator-based tests: using simulation-constructed models to determine contextually relevant agreement thresholds.” BMC Med Res Methodol. 2018; 18:141.

P. D. Marasco, J. S. Hebert, J. W. Sensinger, C. E. Shell, J. S. Schofield, Z. C. Thumser, R. Nataraj, D. T. Beckler, M. R. Dawson, D. H. Blustein, S. Gill, B. D. Mensh, R. Granja-Vazquez, M. D. Newcomb, J. P. Carey, B. M. Orzell. "Illusory movement perception improves motor control for prosthetic hands." Sci. Transl. Med. 10, eaao6990 (2018).

Blustein, Daniel H., and Jonathon W. Sensinger. "Validation of a constrained-time movement task for use in rehabilitation outcome measures." In Rehabilitation Robotics (ICORR), 2017 International Conference on, pp. 1183-1188. IEEE, 2017.

Wilson, Adam W., Daniel H. Blustein, and Jon W. Sensinger. "A third arm—Design of a bypass prosthesis enabling incorporation." In Rehabilitation Robotics (ICORR), 2017 International Conference on, pp. 1381-1386. IEEE, 2017.

Physiologically Relevant Prosthetic Limb Movement Feedback for Upper and Lower Extremity Amputees

We are developing a wearable robotic perceptual feedback system to provide vibrational input as part of a prosthetic socket interface. We are using cognitive/perceptual approaches to provide physiologically relevant vibration-induced joint movement feedback in upper and lower limbs for normal amputees without a neural-machine-interface.

Department of Defense, Congressionally Directed Medical Research Program (CDMRP) Clinical and Rehabilitative Medicine Research Program (CRMRP) Grant #MR140156

Advanced Materials to Improve Moisture Management for Prosthetic Socket Liners

We are working to develop a new prosthetic socket liner material to transport and sequester sweat away from an amputee’s skin. The number of amputees, particularly double- and triple-amputees, in our veteran population has steadily increased over the last decade. Meanwhile, advances in prosthesis technology have produced devices with increasing functional potential of which our veteran amputee users want to take full advantage. In contrast, conventional silicone socket liners have advanced relatively little, including an undesirable tendency to accumulate sweat during use, particularly for physically active amputees. A liner material which keeps this moisture away from the user’s skin would not only improve comfort and hygiene, but also the critically-important fit and thus the overall performance of the prosthesis.

Department of Veterans Affairs, Merit Review, 1 I01 RX001833-01A2

Pulsed Electromagnetic Frequency (PEMF) Stimulation of Mechanosensory Nerves Affecting Bone

We are investigating the use of differing fundamental frequency and magnetic field strength characteristics of Pulsed Electromagnetic Field (PEMF) treatment on mechanosensory nerve action potentials in the hind limbs of skeletally mature rats.
Orthofix, Inc. sponsored research agreement, co-investigator 

Recent Projects

Restoring Upper Limb Movement Sense to Amputees; A Move Towards Natural Control of Prosthetic Limbs

We are using cognitive and perceptual approaches and a direct neural-machine interface to provide prosthetic limbs with a physiologically relevant sense of complex synergistic hand movements.

National Institutes of Health (NIH) Director’s Transformative R01 Research Award, 1R01NS081710 – 01

Proprioception in Preclinical Model Cortex to Examine Sensory Feedback for Prosthetics

In this project we used a rat model to investigate how kinesthesia (the sense of limb movement) is organized in the brain.

VA RR&D Career Development Award, Level-2 No. A7253W

Marasco PD, Bourbeau DJ, Shell CE, Granja-Vazquez R, Ina JG (2017)."The neural response properties and cortical organization of a rapidly adapting muscle sensory group response that overlaps with the frequencies that elicit the kinesthetic illusion." PLoS ONE 12(11): e0188559.

A Touch Feedback Tactor Array System for Long-term Implementation of Physiologically Relevant Cutaneous Touch with Prosthetic Limbs

We have developed and implemented a sensory feedback system for prosthetic limbs that is integrated with the amputee’s nerves to provide physiologically relevant cutaneous feedback. It was designed, built, and packaged for long-term take-home use and is being used to examine the malleability of representational plasticity and cognitive effects of visual-tactile integration with use over one year.

Defense Advanced Research Project Agency (DARPA), Department of Defense, 61732-LS-DRP, Under P-1108-114403/DARPA-BAA-11-08 Reliable Peripheral Interfaces (RPI)


Functional Metrics Development

The Laboratory for Bionic Integration is working closely with Jacqueline Hebert, MD, FRCPC, at the University of Alberta and Jon Sensinger, PhD, PEng, of the University of New Brunswick to develop a suite of metrics as sophisticated and effective as the devices that they assess. These tests help map system function, so that they may be used as tools to inform technology design, implementation, and translation. The metrics are designed to not have a ceiling effect in comparison with able-bodied users. They are rooted in functional, real-world tasks and are clinically applicable to users of advanced upper limb sensory-motor integration technologies.

The metrics suite includes:

1. GRIP: Grasping Relative Index of Performance
Developed by the Laboratory for Bionic Integration

The principle tasks for upper-limb prosthesis use involve grasping, gripping, or squeezing. The ability to quickly and accurately apply a desired force is critical for appropriate manual manipulation, from handholding to heavy lifting, and is necessary for obtaining fluid, natural use of a prosthetic hand. Fitts’ law is a widely applicable descriptive model relating the time required to achieve a target to movement size and accuracy. By applying this law to grip forces across the dynamic range of a device we can quantify a relative effective accuracy and index of performance irrespective of control scheme or feedback modality.


2. PEP: Prosthesis Efficiency and Profitability
Developed by the Laboratory for Bionic Integration

Humans use their hands to acquire and manipulate objects for a multitude of activities of daily living. This object acquisition and manipulation involves seam-less interaction between motor control, touch and proprioception. Upper limb prosthetic devices are designed to replace this lost functionality and their intrinsic utility is reflected in their relative functional efficiency. Accepted methodologies from evolutionary ecology provide a mathematical model-based framework for assessing efficiency and profitability in complex biological systems. In this metric, optimal foraging theory is used as a platform to objectively assess the searching, reaching, grasping, manipulating and decision-making movements involved with prosthesis use which directly reflect foraging tasks and behaviors.


3. GaMA: Gaze & Movement Assessment
Developed by the Hebert Lab

As our primary source of sensory information, the movement of our eyes to specific locations is intimately tied to the demands of a task and is an excellent correlate of where we are attending. Visual attention is an integral component of motor performance expected to change with accurate sensory feedback from the prosthesis and intuitive motor control. This metric combines motion tracking and eye tracking during simulated real-world tasks, and enables 3D gaze vector rendering by integrating environmental modeling and the representation of real world objects. This metric identifies the motion of the prosthesis, compensatory body movements and simultaneous visual gaze behavior during performance tasks in integrated 3D space, as well as the location and movement of task-critical objects. Metrics output include upper limb and hand kinematic measures as well as standard measures of visual attention.

4. CBI: Control Bottleneck Index
Developed by the Sensinger Lab

Your brain sends efferent signals which are corrupted by noise. It receives afferent signals from many sources. It forms models that help it predict control and interpret feedback. Good performance can be achieved with many combinations of these three factors, and performance may be limited by a bottleneck in any one of them. In that case, improvements in one of the other factors may not lead to significant improvements in performance until the bottleneck is relieved. The purpose of this metric is to identify the bottleneck in that process for a given task, and to evaluate the contribution of a particular control strategy or sensory feedback modality independent of that bottleneck. This task is appropriate to assess control source and feedback fidelity.

5. PIC: Prosthesis Incorporation
Developed by the Sensinger Lab

The goal of this metric is to quantitatively measure how much a prosthesis has been incorporated into the body schema. Device incorporation is a good indication that control and sensory feedback are intuitive, synchronized, and meaningful. This metric uses a cross-modal congruency effect paradigm to evaluate prosthesis incorporation, in which the ability of a person to ignore one form of feedback in favor of another is assessed. The metric provides an index that can be assessed quickly and accurately using a simple standardized setup. This task is appropriate to assess control source and tactile feedback fidelity.

Using the Metrics Suite in Your Research

If you are interested in using the functional metrics suite in your research, please email Dr. Paul Marasco at

To find publications relating to the functional metrics suite, please visit the current projects page of our site.

Paul D. Marasco
Paul D. Marasco
Associate Staff

Dr. Marasco is a neuroscientist (sensory neurophysiology) who focuses on applied cognitive/perceptual systems integration within a biomedical engineering context. He is an Associate Staff Scientist in the Lerner Research Institute Department of Biomedical Engineering at Cleveland Clinic and a Principal Investigator in the Advanced Platform Technology Center of Excellence at the Louis Stokes Cleveland Department of Veterans Affairs Medical Center, where he is also the Director of Amputee Research for the Department of Physical Medicine and Rehabilitation. He heads the Laboratory for Bionic Integration where neural-machine-interfaces are used to provide touch and movement sensation to prosthetic limbs so that individuals with amputation feel like the devices are a part of their body. Dr. Marasco leads a number of multi-institution and international projects funded across the National Institutes of Health (NIH), the Defense Advanced Research Projects Administration (DARPA), the Department of Defense’s Congressionally Directed Medical Research Program (CDMRP), and the Veterans Administration (VA).

In addition to investigating how to use perception and cognition to make prosthetics feel, Dr. Marasco and his teams are also working to develop new validated functional tests for advanced prosthetic systems to measure the tangible benefit of improved sensation on the use of prosthetic devices and help communicate the outcomes to clinicians and payers. They are providing joint movement sensations to amputees without neural-machine-interfaces so that they can move and walk better, and also developing advanced composite approaches to make silicone socket liners more comfortable. Through the VA, Dr. Marasco was recently awarded the Presidential Early Career Award for Scientists and Engineers, which is the highest honor bestowed by the U.S. government on outstanding scientists and engineers beginning their independent careers in the Federal Services.

Dylan  Beckler
Dylan Beckler
Research Engineer

Dylan Beckler joined the Laboratory for Bionic Integration in 2016 as a full-time Research Engineer. Dylan earned his Bachelors of Science in Biomedical Engineering from the University of Akron in 2015. His area of research is focused on developing functional tests for advanced prosthetic limbs using Optimal Foraging Theory approaches.

Kaleigh  Farrell
Kaleigh Farrell
Research Coordinator

Kaleigh Farrell joined the Marasco lab in 2015 as a Research Coordinator. She is a graduate of Miami University in Oxford, Ohio, with a Bachelor of Arts in Psychology.

Kaleigh’s focus is on the regulatory aspects of research coordination. She functions as our liaison with the IRB and our sponsors’ regulatory agencies.

Zachary  Thumser
Zachary Thumser
Visiting Researcher

Zachary earned his MS in biomedical engineering from the University of Michigan in 2003. While there, his graduate work focused on bioelectronics.

In 2005 he joined Dr. John Stahl's lab at the Cleveland VA Medical Center's Ocular Motility Laboratory studying eye-head coordination and cerebellar gaze control disorders.

In 2013 he joined Dr. Marasco as a Research Engineer studying sensory feedback and integration in prosthetic limbs, with a focus on developing functional metrics of limb performance, as well as physically implementing the various technologies and approaches used by the lab.


03/10/2022 |  

BME Researcher Receives Award from the Clinical Research Forum for Pioneering Bionic Arm Study

Dr. Marasco was honored for engineering a prosthetic that allows the wearer to “think” and function like an able-bodied person.

09/01/2021 |  

Researchers Develop Bionic Arm that Restores Natural Behaviors in Patients with Amputations

Dr. Marasco and his collaborators designed a novel system that combines intuitive motor control, touch and grip kinesthesia for patients with upper-limb amputations.


Postdoctoral Fellows

We are currently seeking postdoctoral research fellows to work in the Laboratory for Bionic Integration at the Biomedical Engineering Department of Cleveland Clinic's Lerner Research Institute. Successful applicants must be excited to work within a multidisciplinary team of researchers, neuroscientists, engineers and clinicians. Candidate must have a strong research background as demonstrated through journal publications, and high-level conference participation. Applicants must be independent and highly motivated with a PhD in Biomedical Engineering, Neuro Sciences, Physiology, Electrical Engineering, Mechanical Engineering or related field.

As a Postdoctoral fellow you will be expected to lead exciting research contributing to the fields of neural-machine interfaces, limb prosthesis, or the mechanistic understandings of sensory processes. Previous experience with human or preclinical trials is preferred. Qualified applicants should submit a one-page research statement and a CV to Dr. Paul Marasco,

Undergraduate and Graduate Student Internships

The Laboratory for Bionic Integration welcomes applications for internships from interested undergraduate and graduate students. Internships are available during the academic semester and over the summer.

Students seeking internships are required to send a letter of intent, CV or resume, and transcript (unofficial is acceptable) to Dr. Paul Marasco at for consideration. Internship applications are accepted and interviews scheduled on a rolling basis.

An intern’s individual research interests and experience will shape the course of their internship project.

Please note that due to departmental restrictions, we are unable to accept high school student interns.


Biomedical Engineering
Lerner Research Institute
9500 Euclid Avenue
Cleveland, Ohio 44195

Paul D. Marasco, PhD
Associate Staff
Phone: 216.444.1217
Fax: 216.444.9198